diff mbox

rt2x00: improve calling conventions for register accessors

Message ID 20170515134711.2770374-1-arnd@arndb.de
State New
Headers show

Commit Message

Arnd Bergmann May 15, 2017, 1:46 p.m. UTC 
With CONFIG_KASAN enabled and gcc-7, we get a warning about rather high
stack usage (with a private patch set I have to turn on this warning,
which I intend to get into the next kernel release):

wireless/ralink/rt2x00/rt2800lib.c: In function 'rt2800_bw_filter_calibration':
wireless/ralink/rt2x00/rt2800lib.c:7990:1: error: the frame size of 2144 bytes is larger than 1536 bytes [-Werror=frame-larger-than=]

The problem is that KASAN inserts a redzone around each local variable that
gets passed by reference, and the newly added function has a lot of them.
We can easily avoid that here by changing the calling convention to have
the output as the return value of the function. This should also results in
smaller object code, saving around 4KB in .text with KASAN, or 2KB without
KASAN.

Fixes: 41977e86c984 ("rt2x00: add support for MT7620")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

---
 drivers/net/wireless/ralink/rt2x00/rt2800lib.c | 319 +++++++++++++------------
 1 file changed, 164 insertions(+), 155 deletions(-)

-- 
2.9.0

Comments

Stanislaw Gruszka May 15, 2017, 2:28 p.m. UTC | #1 
On Mon, May 15, 2017 at 03:46:55PM +0200, Arnd Bergmann wrote:
> With CONFIG_KASAN enabled and gcc-7, we get a warning about rather high

> stack usage (with a private patch set I have to turn on this warning,

> which I intend to get into the next kernel release):

> 

> wireless/ralink/rt2x00/rt2800lib.c: In function 'rt2800_bw_filter_calibration':

> wireless/ralink/rt2x00/rt2800lib.c:7990:1: error: the frame size of 2144 bytes is larger than 1536 bytes [-Werror=frame-larger-than=]

> 

> The problem is that KASAN inserts a redzone around each local variable that

> gets passed by reference, and the newly added function has a lot of them.

> We can easily avoid that here by changing the calling convention to have

> the output as the return value of the function. This should also results in

> smaller object code, saving around 4KB in .text with KASAN, or 2KB without

> KASAN.

> 

> Fixes: 41977e86c984 ("rt2x00: add support for MT7620")

> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

> ---

>  drivers/net/wireless/ralink/rt2x00/rt2800lib.c | 319 +++++++++++++------------

>  1 file changed, 164 insertions(+), 155 deletions(-)


We have read(, &val) calling convention since forever in rt2x00 and that
was never a problem. I dislike to change that now to make some tools
happy, I think problem should be fixed in the tools instead.

Stanislaw
Arnd Bergmann May 15, 2017, 2:36 p.m. UTC | #2 
On Mon, May 15, 2017 at 4:28 PM, Stanislaw Gruszka <sgruszka@redhat.com> wrote:
> On Mon, May 15, 2017 at 03:46:55PM +0200, Arnd Bergmann wrote:

>> With CONFIG_KASAN enabled and gcc-7, we get a warning about rather high

>> stack usage (with a private patch set I have to turn on this warning,

>> which I intend to get into the next kernel release):

>>

>> wireless/ralink/rt2x00/rt2800lib.c: In function 'rt2800_bw_filter_calibration':

>> wireless/ralink/rt2x00/rt2800lib.c:7990:1: error: the frame size of 2144 bytes is larger than 1536 bytes [-Werror=frame-larger-than=]

>>

>> The problem is that KASAN inserts a redzone around each local variable that

>> gets passed by reference, and the newly added function has a lot of them.

>> We can easily avoid that here by changing the calling convention to have

>> the output as the return value of the function. This should also results in

>> smaller object code, saving around 4KB in .text with KASAN, or 2KB without

>> KASAN.

>>

>> Fixes: 41977e86c984 ("rt2x00: add support for MT7620")

>> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

>> ---

>>  drivers/net/wireless/ralink/rt2x00/rt2800lib.c | 319 +++++++++++++------------

>>  1 file changed, 164 insertions(+), 155 deletions(-)

>

> We have read(, &val) calling convention since forever in rt2x00 and that

> was never a problem. I dislike to change that now to make some tools

> happy, I think problem should be fixed in the tools instead.


How about adding 'depends on !KASAN' in Kconfig instead?

       Arnd
David Miller May 15, 2017, 2:39 p.m. UTC | #3 
From: Stanislaw Gruszka <sgruszka@redhat.com>

Date: Mon, 15 May 2017 16:28:01 +0200

> On Mon, May 15, 2017 at 03:46:55PM +0200, Arnd Bergmann wrote:

>> With CONFIG_KASAN enabled and gcc-7, we get a warning about rather high

>> stack usage (with a private patch set I have to turn on this warning,

>> which I intend to get into the next kernel release):

>> 

>> wireless/ralink/rt2x00/rt2800lib.c: In function 'rt2800_bw_filter_calibration':

>> wireless/ralink/rt2x00/rt2800lib.c:7990:1: error: the frame size of 2144 bytes is larger than 1536 bytes [-Werror=frame-larger-than=]

>> 

>> The problem is that KASAN inserts a redzone around each local variable that

>> gets passed by reference, and the newly added function has a lot of them.

>> We can easily avoid that here by changing the calling convention to have

>> the output as the return value of the function. This should also results in

>> smaller object code, saving around 4KB in .text with KASAN, or 2KB without

>> KASAN.

>> 

>> Fixes: 41977e86c984 ("rt2x00: add support for MT7620")

>> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

>> ---

>>  drivers/net/wireless/ralink/rt2x00/rt2800lib.c | 319 +++++++++++++------------

>>  1 file changed, 164 insertions(+), 155 deletions(-)

> 

> We have read(, &val) calling convention since forever in rt2x00 and that

> was never a problem. I dislike to change that now to make some tools

> happy, I think problem should be fixed in the tools instead.


Passing return values by reference is and always has been a really
poor way to achieve what these functions are doing.

And frankly, whilst the tool could see what's going on here better, we
should be making code easier rather than more difficult to audit.

I am therefore very much in favor of Arnd's change.

This isn't even a situation where there are multiple return values,
such as needing to signal an error and return an unsigned value at the
same time.

These functions return _one_ value, and therefore they should be
returned as a true return value.

Thanks.
David Miller May 15, 2017, 2:40 p.m. UTC | #4 
From: Arnd Bergmann <arnd@arndb.de>

Date: Mon, 15 May 2017 16:36:45 +0200

> On Mon, May 15, 2017 at 4:28 PM, Stanislaw Gruszka <sgruszka@redhat.com> wrote:

>> On Mon, May 15, 2017 at 03:46:55PM +0200, Arnd Bergmann wrote:

>>> With CONFIG_KASAN enabled and gcc-7, we get a warning about rather high

>>> stack usage (with a private patch set I have to turn on this warning,

>>> which I intend to get into the next kernel release):

>>>

>>> wireless/ralink/rt2x00/rt2800lib.c: In function 'rt2800_bw_filter_calibration':

>>> wireless/ralink/rt2x00/rt2800lib.c:7990:1: error: the frame size of 2144 bytes is larger than 1536 bytes [-Werror=frame-larger-than=]

>>>

>>> The problem is that KASAN inserts a redzone around each local variable that

>>> gets passed by reference, and the newly added function has a lot of them.

>>> We can easily avoid that here by changing the calling convention to have

>>> the output as the return value of the function. This should also results in

>>> smaller object code, saving around 4KB in .text with KASAN, or 2KB without

>>> KASAN.

>>>

>>> Fixes: 41977e86c984 ("rt2x00: add support for MT7620")

>>> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

>>> ---

>>>  drivers/net/wireless/ralink/rt2x00/rt2800lib.c | 319 +++++++++++++------------

>>>  1 file changed, 164 insertions(+), 155 deletions(-)

>>

>> We have read(, &val) calling convention since forever in rt2x00 and that

>> was never a problem. I dislike to change that now to make some tools

>> happy, I think problem should be fixed in the tools instead.

> 

> How about adding 'depends on !KASAN' in Kconfig instead?


Please let's not go down that route and make such facilities less
useful due to decreased coverage.

Thanks.
Stanislaw Gruszka May 16, 2017, 11:55 a.m. UTC | #5 
On Mon, May 15, 2017 at 10:39:51AM -0400, David Miller wrote:
> From: Stanislaw Gruszka <sgruszka@redhat.com>

> Date: Mon, 15 May 2017 16:28:01 +0200

> 

> > On Mon, May 15, 2017 at 03:46:55PM +0200, Arnd Bergmann wrote:

> >> With CONFIG_KASAN enabled and gcc-7, we get a warning about rather high

> >> stack usage (with a private patch set I have to turn on this warning,

> >> which I intend to get into the next kernel release):

> >> 

> >> wireless/ralink/rt2x00/rt2800lib.c: In function 'rt2800_bw_filter_calibration':

> >> wireless/ralink/rt2x00/rt2800lib.c:7990:1: error: the frame size of 2144 bytes is larger than 1536 bytes [-Werror=frame-larger-than=]

> >> 

> >> The problem is that KASAN inserts a redzone around each local variable that

> >> gets passed by reference, and the newly added function has a lot of them.

> >> We can easily avoid that here by changing the calling convention to have

> >> the output as the return value of the function. This should also results in

> >> smaller object code, saving around 4KB in .text with KASAN, or 2KB without

> >> KASAN.

> >> 

> >> Fixes: 41977e86c984 ("rt2x00: add support for MT7620")

> >> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

> >> ---

> >>  drivers/net/wireless/ralink/rt2x00/rt2800lib.c | 319 +++++++++++++------------

> >>  1 file changed, 164 insertions(+), 155 deletions(-)

> > 

> > We have read(, &val) calling convention since forever in rt2x00 and that

> > was never a problem. I dislike to change that now to make some tools

> > happy, I think problem should be fixed in the tools instead.

> 

> Passing return values by reference is and always has been a really

> poor way to achieve what these functions are doing.

> 

> And frankly, whilst the tool could see what's going on here better, we

> should be making code easier rather than more difficult to audit.

> 

> I am therefore very much in favor of Arnd's change.

> 

> This isn't even a situation where there are multiple return values,

> such as needing to signal an error and return an unsigned value at the

> same time.

> 

> These functions return _one_ value, and therefore they should be

> returned as a true return value.


In rt2x00 driver we use poor convention in other kind of registers
accessors like bbp, mac, eeprom. I dislike to changing only rfcsr
accessors and leaving others in the old way. And changing all accessors
would be massive and error prone change, which I'm not prefer either.

Arnd, could this be fixed by refactoring rt2800_bw_filter_calibration()
function (which is enormous and definitely should be split into smaller
subroutines) ? If not, I would accept this patch.

Thanks
Stanislaw
Stanislaw Gruszka May 16, 2017, 12:43 p.m. UTC | #6 
On Tue, May 16, 2017 at 01:58:56PM +0200, Johannes Berg wrote:
> On Tue, 2017-05-16 at 13:55 +0200, Stanislaw Gruszka wrote:

> > 

> > In rt2x00 driver we use poor convention in other kind of registers

> > accessors like bbp, mac, eeprom. I dislike to changing only rfcsr

> > accessors and leaving others in the old way. And changing all

> > accessors would be massive and error prone change, which I'm not

> > prefer either.

> 

> That's a stupid argument, but for the sake of it - the conversion can

> easily be done with coccinelle/spatch without being "error prone".


Sure, but still I think it would be preferable to fix newly added
rt2800_bw_filter_calibration() function, instead of ancient rfcsr
accessors.

Stanislaw
Jes Sorensen May 16, 2017, 1:44 p.m. UTC | #7 
On 05/16/2017 07:55 AM, Stanislaw Gruszka wrote:
> On Mon, May 15, 2017 at 10:39:51AM -0400, David Miller wrote:

>> Passing return values by reference is and always has been a really

>> poor way to achieve what these functions are doing.

>>

>> And frankly, whilst the tool could see what's going on here better, we

>> should be making code easier rather than more difficult to audit.

>>

>> I am therefore very much in favor of Arnd's change.

>>

>> This isn't even a situation where there are multiple return values,

>> such as needing to signal an error and return an unsigned value at the

>> same time.

>>

>> These functions return _one_ value, and therefore they should be

>> returned as a true return value.

> 

> In rt2x00 driver we use poor convention in other kind of registers

> accessors like bbp, mac, eeprom. I dislike to changing only rfcsr

> accessors and leaving others in the old way. And changing all accessors

> would be massive and error prone change, which I'm not prefer either.


That's why you do it in multiple smaller patches rather than one ugly 
giant patch.

The rt2x00 current register accessor functions makes the Realtek vendor 
driver equivalent ones look pretty, which is saying something.

Jes
Arnd Bergmann May 16, 2017, 2:19 p.m. UTC | #8 
On Tue, May 16, 2017 at 3:44 PM, Jes Sorensen <jes.sorensen@gmail.com> wrote:
> On 05/16/2017 07:55 AM, Stanislaw Gruszka wrote:

>>

>> On Mon, May 15, 2017 at 10:39:51AM -0400, David Miller wrote:

>>>

>>> Passing return values by reference is and always has been a really

>>> poor way to achieve what these functions are doing.

>>>

>>> And frankly, whilst the tool could see what's going on here better, we

>>> should be making code easier rather than more difficult to audit.

>>>

>>> I am therefore very much in favor of Arnd's change.

>>>

>>> This isn't even a situation where there are multiple return values,

>>> such as needing to signal an error and return an unsigned value at the

>>> same time.

>>>

>>> These functions return _one_ value, and therefore they should be

>>> returned as a true return value.

>>

>>

>> In rt2x00 driver we use poor convention in other kind of registers

>> accessors like bbp, mac, eeprom. I dislike to changing only rfcsr

>> accessors and leaving others in the old way. And changing all accessors

>> would be massive and error prone change, which I'm not prefer either.

>

>

> That's why you do it in multiple smaller patches rather than one ugly giant

> patch.


I did  the first step using a search&replace in vim using

s:\(rt2800_rfcsr_read(.*,.*\), &\(.*\));:\2 = \1);:

but had to introduce a conversion function

static void rt2800_rfcsr_readreg(struct rt2x00_dev *rt2x00dev,
                                const unsigned int word, u8 *value)
{
       *value = rt2800_rfcsr_read(rt2x00dev, word);
}

to keep the correct types in place for struct rt2x00debug. I now
did all the other ones too, and removed that helper again. The
result in much nicer, but I basically ended up having to do
the same regex search for all of these at once:

static void rt2400pci_bbp_read(struct rt2x00_dev *rt2x00dev,
static void rt2500pci_bbp_read(struct rt2x00_dev *rt2x00dev,
static void rt2500usb_register_read(struct rt2x00_dev *rt2x00dev,
static void rt2500usb_register_read_lock(struct rt2x00_dev *rt2x00dev,
static void rt2500usb_bbp_read(struct rt2x00_dev *rt2x00dev,
static void _rt2500usb_register_read(struct rt2x00_dev *rt2x00dev,
static void rt2800_bbp_read(struct rt2x00_dev *rt2x00dev,
static void rt2800_eeprom_read(struct rt2x00_dev *rt2x00dev,
static void rt2800_rfcsr_readreg(struct rt2x00_dev *rt2x00dev,
static void rt2800_bbp_dcoc_read(struct rt2x00_dev *rt2x00dev,
void (*register_read)(struct rt2x00_dev *rt2x00dev,
void (*register_read_lock)(struct rt2x00_dev *rt2x00dev,
static inline void rt2800_register_read(struct rt2x00_dev *rt2x00dev,
static inline void rt2800_register_read_lock(struct rt2x00_dev *rt2x00dev,
static inline void rt2x00_rf_read(struct rt2x00_dev *rt2x00dev,
static inline void rt2x00_eeprom_read(struct rt2x00_dev *rt2x00dev,
void (*read)(struct rt2x00_dev *rt2x00dev, \
static inline void rt2x00mmio_register_read(struct rt2x00_dev *rt2x00dev,
static inline void _rt2x00_desc_read(__le32 *desc, const u8 word, __le32 *value)
static inline void rt2x00_desc_read(__le32 *desc, const u8 word, u32 *value)
static inline void rt2x00usb_register_read(struct rt2x00_dev *rt2x00dev,
static inline void rt2x00usb_register_read_lock(struct rt2x00_dev *rt2x00dev,
static void rt61pci_bbp_read(struct rt2x00_dev *rt2x00dev,
static void rt73usb_bbp_read(struct rt2x00_dev *rt2x00dev,

and that ended up as a 300KB patch [1]. Splitting it up is clearly possibly,
but I fear that would be more error-prone as we then need to add
those helpers for the other debug stuff as well, and remove it again
afterwards.

     Arnd

[1] https://pastebin.com/raw/Qis257mG
David Miller May 16, 2017, 3:37 p.m. UTC | #9 
From: Johannes Berg <johannes@sipsolutions.net>

Date: Tue, 16 May 2017 13:58:56 +0200

> On Tue, 2017-05-16 at 13:55 +0200, Stanislaw Gruszka wrote:

>> 

>> In rt2x00 driver we use poor convention in other kind of registers

>> accessors like bbp, mac, eeprom. I dislike to changing only rfcsr

>> accessors and leaving others in the old way. And changing all

>> accessors would be massive and error prone change, which I'm not

>> prefer either.

> 

> That's a stupid argument, but for the sake of it - the conversion can

> easily be done with coccinelle/spatch without being "error prone".


Agreed, we have tools for this.
diff mbox

Patch

diff --git a/drivers/net/wireless/ralink/rt2x00/rt2800lib.c b/drivers/net/wireless/ralink/rt2x00/rt2800lib.c
index d11c7b210e81..cafcf43436b9 100644
--- a/drivers/net/wireless/ralink/rt2x00/rt2800lib.c
+++ b/drivers/net/wireless/ralink/rt2x00/rt2800lib.c
@@ -203,10 +203,11 @@  static void rt2800_rfcsr_write_dccal(struct rt2x00_dev *rt2x00dev,
 	rt2800_rfcsr_write_bank(rt2x00dev, 7, reg, value);
 }
 
-static void rt2800_rfcsr_read(struct rt2x00_dev *rt2x00dev,
-			      const unsigned int word, u8 *value)
+static u8 rt2800_rfcsr_read(struct rt2x00_dev *rt2x00dev,
+			      const unsigned int word)
 {
 	u32 reg;
+	u8 value;
 
 	mutex_lock(&rt2x00dev->csr_mutex);
 
@@ -232,7 +233,7 @@  static void rt2800_rfcsr_read(struct rt2x00_dev *rt2x00dev,
 			WAIT_FOR_RFCSR_MT7620(rt2x00dev, &reg);
 		}
 
-		*value = rt2x00_get_field32(reg, RF_CSR_CFG_DATA_MT7620);
+		value = rt2x00_get_field32(reg, RF_CSR_CFG_DATA_MT7620);
 		break;
 
 	default:
@@ -247,17 +248,19 @@  static void rt2800_rfcsr_read(struct rt2x00_dev *rt2x00dev,
 			WAIT_FOR_RFCSR(rt2x00dev, &reg);
 		}
 
-		*value = rt2x00_get_field32(reg, RF_CSR_CFG_DATA);
+		value = rt2x00_get_field32(reg, RF_CSR_CFG_DATA);
 		break;
 	}
 
 	mutex_unlock(&rt2x00dev->csr_mutex);
+
+	return value;
 }
 
-static void rt2800_rfcsr_read_bank(struct rt2x00_dev *rt2x00dev, const u8 bank,
-				   const unsigned int reg, u8 *value)
+static u8 rt2800_rfcsr_read_bank(struct rt2x00_dev *rt2x00dev, const u8 bank,
+				   const unsigned int reg)
 {
-	rt2800_rfcsr_read(rt2x00dev, (reg | (bank << 6)), value);
+	return rt2800_rfcsr_read(rt2x00dev, (reg | (bank << 6)));
 }
 
 static void rt2800_rf_write(struct rt2x00_dev *rt2x00dev,
@@ -1225,6 +1228,12 @@  void rt2800_clear_beacon(struct queue_entry *entry)
 EXPORT_SYMBOL_GPL(rt2800_clear_beacon);
 
 #ifdef CONFIG_RT2X00_LIB_DEBUGFS
+static void rt2800_rfcsr_readreg(struct rt2x00_dev *rt2x00dev,
+				 const unsigned int word, u8 *value)
+{
+	*value = rt2800_rfcsr_read(rt2x00dev, word);
+}
+
 const struct rt2x00debug rt2800_rt2x00debug = {
 	.owner	= THIS_MODULE,
 	.csr	= {
@@ -1260,7 +1269,7 @@  const struct rt2x00debug rt2800_rt2x00debug = {
 		.word_count	= RF_SIZE / sizeof(u32),
 	},
 	.rfcsr	= {
-		.read		= rt2800_rfcsr_read,
+		.read		= rt2800_rfcsr_readreg,
 		.write		= rt2800_rfcsr_write,
 		.word_base	= RFCSR_BASE,
 		.word_size	= sizeof(u8),
@@ -2072,7 +2081,7 @@  static void rt2800_freq_cal_mode1(struct rt2x00_dev *rt2x00dev)
 	freq_offset = rt2x00_get_field8(rt2x00dev->freq_offset, RFCSR17_CODE);
 	freq_offset = min_t(u8, freq_offset, FREQ_OFFSET_BOUND);
 
-	rt2800_rfcsr_read(rt2x00dev, 17, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 17);
 	prev_rfcsr = rfcsr;
 
 	rt2x00_set_field8(&rfcsr, RFCSR17_CODE, freq_offset);
@@ -2174,23 +2183,23 @@  static void rt2800_config_channel_rf3xxx(struct rt2x00_dev *rt2x00dev,
 
 	rt2800_rfcsr_write(rt2x00dev, 2, rf->rf1);
 
-	rt2800_rfcsr_read(rt2x00dev, 3, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 3);
 	rt2x00_set_field8(&rfcsr, RFCSR3_K, rf->rf3);
 	rt2800_rfcsr_write(rt2x00dev, 3, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 6, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 6);
 	rt2x00_set_field8(&rfcsr, RFCSR6_R1, rf->rf2);
 	rt2800_rfcsr_write(rt2x00dev, 6, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 12, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 12);
 	rt2x00_set_field8(&rfcsr, RFCSR12_TX_POWER, info->default_power1);
 	rt2800_rfcsr_write(rt2x00dev, 12, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 13, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 13);
 	rt2x00_set_field8(&rfcsr, RFCSR13_TX_POWER, info->default_power2);
 	rt2800_rfcsr_write(rt2x00dev, 13, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 1, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 1);
 	rt2x00_set_field8(&rfcsr, RFCSR1_RX0_PD, 0);
 	rt2x00_set_field8(&rfcsr, RFCSR1_RX1_PD,
 			  rt2x00dev->default_ant.rx_chain_num <= 1);
@@ -2203,7 +2212,7 @@  static void rt2800_config_channel_rf3xxx(struct rt2x00_dev *rt2x00dev,
 			  rt2x00dev->default_ant.tx_chain_num <= 2);
 	rt2800_rfcsr_write(rt2x00dev, 1, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 23, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 23);
 	rt2x00_set_field8(&rfcsr, RFCSR23_FREQ_OFFSET, rt2x00dev->freq_offset);
 	rt2800_rfcsr_write(rt2x00dev, 23, rfcsr);
 
@@ -2220,19 +2229,19 @@  static void rt2800_config_channel_rf3xxx(struct rt2x00_dev *rt2x00dev,
 		}
 	}
 
-	rt2800_rfcsr_read(rt2x00dev, 24, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 24);
 	rt2x00_set_field8(&rfcsr, RFCSR24_TX_CALIB, calib_tx);
 	rt2800_rfcsr_write(rt2x00dev, 24, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 31, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 31);
 	rt2x00_set_field8(&rfcsr, RFCSR31_RX_CALIB, calib_rx);
 	rt2800_rfcsr_write(rt2x00dev, 31, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 7, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 7);
 	rt2x00_set_field8(&rfcsr, RFCSR7_RF_TUNING, 1);
 	rt2800_rfcsr_write(rt2x00dev, 7, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 30, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 30);
 	rt2x00_set_field8(&rfcsr, RFCSR30_RF_CALIBRATION, 1);
 	rt2800_rfcsr_write(rt2x00dev, 30, rfcsr);
 
@@ -2262,7 +2271,7 @@  static void rt2800_config_channel_rf3052(struct rt2x00_dev *rt2x00dev,
 	rt2800_rfcsr_write(rt2x00dev, 2, rf->rf1);
 	rt2800_rfcsr_write(rt2x00dev, 3, rf->rf3);
 
-	rt2800_rfcsr_read(rt2x00dev, 6, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 6);
 	rt2x00_set_field8(&rfcsr, RFCSR6_R1, rf->rf2);
 	if (rf->channel <= 14)
 		rt2x00_set_field8(&rfcsr, RFCSR6_TXDIV, 2);
@@ -2270,14 +2279,14 @@  static void rt2800_config_channel_rf3052(struct rt2x00_dev *rt2x00dev,
 		rt2x00_set_field8(&rfcsr, RFCSR6_TXDIV, 1);
 	rt2800_rfcsr_write(rt2x00dev, 6, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 5, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 5);
 	if (rf->channel <= 14)
 		rt2x00_set_field8(&rfcsr, RFCSR5_R1, 1);
 	else
 		rt2x00_set_field8(&rfcsr, RFCSR5_R1, 2);
 	rt2800_rfcsr_write(rt2x00dev, 5, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 12, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 12);
 	if (rf->channel <= 14) {
 		rt2x00_set_field8(&rfcsr, RFCSR12_DR0, 3);
 		rt2x00_set_field8(&rfcsr, RFCSR12_TX_POWER,
@@ -2290,7 +2299,7 @@  static void rt2800_config_channel_rf3052(struct rt2x00_dev *rt2x00dev,
 	}
 	rt2800_rfcsr_write(rt2x00dev, 12, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 13, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 13);
 	if (rf->channel <= 14) {
 		rt2x00_set_field8(&rfcsr, RFCSR13_DR0, 3);
 		rt2x00_set_field8(&rfcsr, RFCSR13_TX_POWER,
@@ -2303,7 +2312,7 @@  static void rt2800_config_channel_rf3052(struct rt2x00_dev *rt2x00dev,
 	}
 	rt2800_rfcsr_write(rt2x00dev, 13, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 1, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 1);
 	rt2x00_set_field8(&rfcsr, RFCSR1_RX0_PD, 0);
 	rt2x00_set_field8(&rfcsr, RFCSR1_TX0_PD, 0);
 	rt2x00_set_field8(&rfcsr, RFCSR1_RX1_PD, 0);
@@ -2336,7 +2345,7 @@  static void rt2800_config_channel_rf3052(struct rt2x00_dev *rt2x00dev,
 	}
 	rt2800_rfcsr_write(rt2x00dev, 1, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 23, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 23);
 	rt2x00_set_field8(&rfcsr, RFCSR23_FREQ_OFFSET, rt2x00dev->freq_offset);
 	rt2800_rfcsr_write(rt2x00dev, 23, rfcsr);
 
@@ -2366,7 +2375,7 @@  static void rt2800_config_channel_rf3052(struct rt2x00_dev *rt2x00dev,
 		rt2800_rfcsr_write(rt2x00dev, 27, 0x00);
 		rt2800_rfcsr_write(rt2x00dev, 29, 0x9b);
 	} else {
-		rt2800_rfcsr_read(rt2x00dev, 7, &rfcsr);
+		rfcsr = rt2800_rfcsr_read(rt2x00dev, 7);
 		rt2x00_set_field8(&rfcsr, RFCSR7_BIT2, 1);
 		rt2x00_set_field8(&rfcsr, RFCSR7_BIT3, 0);
 		rt2x00_set_field8(&rfcsr, RFCSR7_BIT4, 1);
@@ -2407,7 +2416,7 @@  static void rt2800_config_channel_rf3052(struct rt2x00_dev *rt2x00dev,
 		rt2x00_set_field32(&reg, GPIO_CTRL_VAL7, 0);
 	rt2800_register_write(rt2x00dev, GPIO_CTRL, reg);
 
-	rt2800_rfcsr_read(rt2x00dev, 7, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 7);
 	rt2x00_set_field8(&rfcsr, RFCSR7_RF_TUNING, 1);
 	rt2800_rfcsr_write(rt2x00dev, 7, rfcsr);
 }
@@ -2450,11 +2459,11 @@  static void rt2800_config_channel_rf3053(struct rt2x00_dev *rt2x00dev,
 	rt2800_rfcsr_write(rt2x00dev, 8, rf->rf1);
 	rt2800_rfcsr_write(rt2x00dev, 9, rf->rf3 & 0xf);
 
-	rt2800_rfcsr_read(rt2x00dev, 11, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 11);
 	rt2x00_set_field8(&rfcsr, RFCSR11_R, (rf->rf2 & 0x3));
 	rt2800_rfcsr_write(rt2x00dev, 11, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 11, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 11);
 	rt2x00_set_field8(&rfcsr, RFCSR11_PLL_IDOH, 1);
 	if (rf->channel <= 14)
 		rt2x00_set_field8(&rfcsr, RFCSR11_PLL_MOD, 1);
@@ -2462,7 +2471,7 @@  static void rt2800_config_channel_rf3053(struct rt2x00_dev *rt2x00dev,
 		rt2x00_set_field8(&rfcsr, RFCSR11_PLL_MOD, 2);
 	rt2800_rfcsr_write(rt2x00dev, 11, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 53, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 53);
 	if (rf->channel <= 14) {
 		rfcsr = 0;
 		rt2x00_set_field8(&rfcsr, RFCSR53_TX_POWER,
@@ -2477,7 +2486,7 @@  static void rt2800_config_channel_rf3053(struct rt2x00_dev *rt2x00dev,
 	}
 	rt2800_rfcsr_write(rt2x00dev, 53, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 55, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 55);
 	if (rf->channel <= 14) {
 		rfcsr = 0;
 		rt2x00_set_field8(&rfcsr, RFCSR55_TX_POWER,
@@ -2492,7 +2501,7 @@  static void rt2800_config_channel_rf3053(struct rt2x00_dev *rt2x00dev,
 	}
 	rt2800_rfcsr_write(rt2x00dev, 55, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 54, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 54);
 	if (rf->channel <= 14) {
 		rfcsr = 0;
 		rt2x00_set_field8(&rfcsr, RFCSR54_TX_POWER,
@@ -2507,7 +2516,7 @@  static void rt2800_config_channel_rf3053(struct rt2x00_dev *rt2x00dev,
 	}
 	rt2800_rfcsr_write(rt2x00dev, 54, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 1, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 1);
 	rt2x00_set_field8(&rfcsr, RFCSR1_RX0_PD, 0);
 	rt2x00_set_field8(&rfcsr, RFCSR1_TX0_PD, 0);
 	rt2x00_set_field8(&rfcsr, RFCSR1_RX1_PD, 0);
@@ -2559,7 +2568,7 @@  static void rt2800_config_channel_rf3053(struct rt2x00_dev *rt2x00dev,
 	/* NOTE: the reference driver does not writes the new value
 	 * back to RFCSR 32
 	 */
-	rt2800_rfcsr_read(rt2x00dev, 32, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 32);
 	rt2x00_set_field8(&rfcsr, RFCSR32_TX_AGC_FC, txrx_agc_fc);
 
 	if (rf->channel <= 14)
@@ -2568,34 +2577,34 @@  static void rt2800_config_channel_rf3053(struct rt2x00_dev *rt2x00dev,
 		rfcsr = 0x80;
 	rt2800_rfcsr_write(rt2x00dev, 31, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 30, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 30);
 	rt2x00_set_field8(&rfcsr, RFCSR30_TX_H20M, txrx_h20m);
 	rt2x00_set_field8(&rfcsr, RFCSR30_RX_H20M, txrx_h20m);
 	rt2800_rfcsr_write(rt2x00dev, 30, rfcsr);
 
 	/* Band selection */
-	rt2800_rfcsr_read(rt2x00dev, 36, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 36);
 	if (rf->channel <= 14)
 		rt2x00_set_field8(&rfcsr, RFCSR36_RF_BS, 1);
 	else
 		rt2x00_set_field8(&rfcsr, RFCSR36_RF_BS, 0);
 	rt2800_rfcsr_write(rt2x00dev, 36, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 34, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 34);
 	if (rf->channel <= 14)
 		rfcsr = 0x3c;
 	else
 		rfcsr = 0x20;
 	rt2800_rfcsr_write(rt2x00dev, 34, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 12, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 12);
 	if (rf->channel <= 14)
 		rfcsr = 0x1a;
 	else
 		rfcsr = 0x12;
 	rt2800_rfcsr_write(rt2x00dev, 12, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 6, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 6);
 	if (rf->channel >= 1 && rf->channel <= 14)
 		rt2x00_set_field8(&rfcsr, RFCSR6_VCO_IC, 1);
 	else if (rf->channel >= 36 && rf->channel <= 64)
@@ -2606,7 +2615,7 @@  static void rt2800_config_channel_rf3053(struct rt2x00_dev *rt2x00dev,
 		rt2x00_set_field8(&rfcsr, RFCSR6_VCO_IC, 1);
 	rt2800_rfcsr_write(rt2x00dev, 6, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 30, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 30);
 	rt2x00_set_field8(&rfcsr, RFCSR30_RX_VCM, 2);
 	rt2800_rfcsr_write(rt2x00dev, 30, rfcsr);
 
@@ -2620,11 +2629,11 @@  static void rt2800_config_channel_rf3053(struct rt2x00_dev *rt2x00dev,
 		rt2800_rfcsr_write(rt2x00dev, 13, 0x23);
 	}
 
-	rt2800_rfcsr_read(rt2x00dev, 51, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 51);
 	rt2x00_set_field8(&rfcsr, RFCSR51_BITS01, 1);
 	rt2800_rfcsr_write(rt2x00dev, 51, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 51, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 51);
 	if (rf->channel <= 14) {
 		rt2x00_set_field8(&rfcsr, RFCSR51_BITS24, 5);
 		rt2x00_set_field8(&rfcsr, RFCSR51_BITS57, 3);
@@ -2634,7 +2643,7 @@  static void rt2800_config_channel_rf3053(struct rt2x00_dev *rt2x00dev,
 	}
 	rt2800_rfcsr_write(rt2x00dev, 51, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 49, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 49);
 	if (rf->channel <= 14)
 		rt2x00_set_field8(&rfcsr, RFCSR49_TX_LO1_IC, 3);
 	else
@@ -2645,11 +2654,11 @@  static void rt2800_config_channel_rf3053(struct rt2x00_dev *rt2x00dev,
 
 	rt2800_rfcsr_write(rt2x00dev, 49, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 50, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 50);
 	rt2x00_set_field8(&rfcsr, RFCSR50_TX_LO1_EN, 0);
 	rt2800_rfcsr_write(rt2x00dev, 50, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 57, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 57);
 	if (rf->channel <= 14)
 		rt2x00_set_field8(&rfcsr, RFCSR57_DRV_CC, 0x1b);
 	else
@@ -2665,7 +2674,7 @@  static void rt2800_config_channel_rf3053(struct rt2x00_dev *rt2x00dev,
 	}
 
 	/* Initiate VCO calibration */
-	rt2800_rfcsr_read(rt2x00dev, 3, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 3);
 	if (rf->channel <= 14) {
 		rt2x00_set_field8(&rfcsr, RFCSR3_VCOCAL_EN, 1);
 	} else {
@@ -2721,11 +2730,11 @@  static void rt2800_config_channel_rf3290(struct rt2x00_dev *rt2x00dev,
 
 	rt2800_rfcsr_write(rt2x00dev, 8, rf->rf1);
 	rt2800_rfcsr_write(rt2x00dev, 9, rf->rf3);
-	rt2800_rfcsr_read(rt2x00dev, 11, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 11);
 	rt2x00_set_field8(&rfcsr, RFCSR11_R, rf->rf2);
 	rt2800_rfcsr_write(rt2x00dev, 11, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 49, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 49);
 	if (info->default_power1 > POWER_BOUND)
 		rt2x00_set_field8(&rfcsr, RFCSR49_TX, POWER_BOUND);
 	else
@@ -2775,7 +2784,7 @@  static void rt2800_config_channel_rf3322(struct rt2x00_dev *rt2x00dev,
 
 	rt2800_freq_cal_mode1(rt2x00dev);
 
-	rt2800_rfcsr_read(rt2x00dev, 1, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 1);
 	rt2x00_set_field8(&rfcsr, RFCSR1_RX0_PD, 1);
 	rt2x00_set_field8(&rfcsr, RFCSR1_TX0_PD, 1);
 
@@ -2806,11 +2815,11 @@  static void rt2800_config_channel_rf53xx(struct rt2x00_dev *rt2x00dev,
 
 	rt2800_rfcsr_write(rt2x00dev, 8, rf->rf1);
 	rt2800_rfcsr_write(rt2x00dev, 9, rf->rf3);
-	rt2800_rfcsr_read(rt2x00dev, 11, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 11);
 	rt2x00_set_field8(&rfcsr, RFCSR11_R, rf->rf2);
 	rt2800_rfcsr_write(rt2x00dev, 11, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 49, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 49);
 	if (info->default_power1 > POWER_BOUND)
 		rt2x00_set_field8(&rfcsr, RFCSR49_TX, POWER_BOUND);
 	else
@@ -2818,7 +2827,7 @@  static void rt2800_config_channel_rf53xx(struct rt2x00_dev *rt2x00dev,
 	rt2800_rfcsr_write(rt2x00dev, 49, rfcsr);
 
 	if (rt2x00_rt(rt2x00dev, RT5392)) {
-		rt2800_rfcsr_read(rt2x00dev, 50, &rfcsr);
+		rfcsr = rt2800_rfcsr_read(rt2x00dev, 50);
 		if (info->default_power2 > POWER_BOUND)
 			rt2x00_set_field8(&rfcsr, RFCSR50_TX, POWER_BOUND);
 		else
@@ -2827,7 +2836,7 @@  static void rt2800_config_channel_rf53xx(struct rt2x00_dev *rt2x00dev,
 		rt2800_rfcsr_write(rt2x00dev, 50, rfcsr);
 	}
 
-	rt2800_rfcsr_read(rt2x00dev, 1, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 1);
 	if (rt2x00_rt(rt2x00dev, RT5392)) {
 		rt2x00_set_field8(&rfcsr, RFCSR1_RX1_PD, 1);
 		rt2x00_set_field8(&rfcsr, RFCSR1_TX1_PD, 1);
@@ -2919,13 +2928,13 @@  static void rt2800_config_channel_rf55xx(struct rt2x00_dev *rt2x00dev,
 	/* Order of values on rf_channel entry: N, K, mod, R */
 	rt2800_rfcsr_write(rt2x00dev, 8, rf->rf1 & 0xff);
 
-	rt2800_rfcsr_read(rt2x00dev,  9, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev,  9);
 	rt2x00_set_field8(&rfcsr, RFCSR9_K, rf->rf2 & 0xf);
 	rt2x00_set_field8(&rfcsr, RFCSR9_N, (rf->rf1 & 0x100) >> 8);
 	rt2x00_set_field8(&rfcsr, RFCSR9_MOD, ((rf->rf3 - 8) & 0x4) >> 2);
 	rt2800_rfcsr_write(rt2x00dev, 9, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 11, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 11);
 	rt2x00_set_field8(&rfcsr, RFCSR11_R, rf->rf4 - 1);
 	rt2x00_set_field8(&rfcsr, RFCSR11_MOD, (rf->rf3 - 8) & 0x3);
 	rt2800_rfcsr_write(rt2x00dev, 11, rfcsr);
@@ -3093,7 +3102,7 @@  static void rt2800_config_channel_rf55xx(struct rt2x00_dev *rt2x00dev,
 		ep_reg = 0x3;
 	}
 
-	rt2800_rfcsr_read(rt2x00dev, 49, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 49);
 	if (info->default_power1 > power_bound)
 		rt2x00_set_field8(&rfcsr, RFCSR49_TX, power_bound);
 	else
@@ -3102,7 +3111,7 @@  static void rt2800_config_channel_rf55xx(struct rt2x00_dev *rt2x00dev,
 		rt2x00_set_field8(&rfcsr, RFCSR49_EP, ep_reg);
 	rt2800_rfcsr_write(rt2x00dev, 49, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 50, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 50);
 	if (info->default_power2 > power_bound)
 		rt2x00_set_field8(&rfcsr, RFCSR50_TX, power_bound);
 	else
@@ -3111,7 +3120,7 @@  static void rt2800_config_channel_rf55xx(struct rt2x00_dev *rt2x00dev,
 		rt2x00_set_field8(&rfcsr, RFCSR50_EP, ep_reg);
 	rt2800_rfcsr_write(rt2x00dev, 50, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 1, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 1);
 	rt2x00_set_field8(&rfcsr, RFCSR1_RF_BLOCK_EN, 1);
 	rt2x00_set_field8(&rfcsr, RFCSR1_PLL_PD, 1);
 
@@ -3144,7 +3153,7 @@  static void rt2800_config_channel_rf55xx(struct rt2x00_dev *rt2x00dev,
 	rt2800_freq_cal_mode1(rt2x00dev);
 
 	/* TODO merge with others */
-	rt2800_rfcsr_read(rt2x00dev, 3, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 3);
 	rt2x00_set_field8(&rfcsr, RFCSR3_VCOCAL_EN, 1);
 	rt2800_rfcsr_write(rt2x00dev, 3, rfcsr);
 
@@ -3186,7 +3195,7 @@  static void rt2800_config_channel_rf7620(struct rt2x00_dev *rt2x00dev,
 	/* Rdiv setting (set 0x03 if Xtal==20)
 	 * R13[1:0]
 	 */
-	rt2800_rfcsr_read(rt2x00dev, 13, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 13);
 	rt2x00_set_field8(&rfcsr, RFCSR13_RDIV_MT7620,
 			  rt2800_clk_is_20mhz(rt2x00dev) ? 3 : 0);
 	rt2800_rfcsr_write(rt2x00dev, 13, rfcsr);
@@ -3195,25 +3204,25 @@  static void rt2800_config_channel_rf7620(struct rt2x00_dev *rt2x00dev,
 	 * R20[7:0] in rf->rf1
 	 * R21[0] always 0
 	 */
-	rt2800_rfcsr_read(rt2x00dev, 20, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 20);
 	rfcsr = (rf->rf1 & 0x00ff);
 	rt2800_rfcsr_write(rt2x00dev, 20, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 21, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 21);
 	rt2x00_set_field8(&rfcsr, RFCSR21_BIT1, 0);
 	rt2800_rfcsr_write(rt2x00dev, 21, rfcsr);
 
 	/* K setting (always 0)
 	 * R16[3:0] (RF PLL freq selection)
 	 */
-	rt2800_rfcsr_read(rt2x00dev, 16, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 16);
 	rt2x00_set_field8(&rfcsr, RFCSR16_RF_PLL_FREQ_SEL_MT7620, 0);
 	rt2800_rfcsr_write(rt2x00dev, 16, rfcsr);
 
 	/* D setting (always 0)
 	 * R22[2:0] (D=15, R22[2:0]=<111>)
 	 */
-	rt2800_rfcsr_read(rt2x00dev, 22, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 22);
 	rt2x00_set_field8(&rfcsr, RFCSR22_FREQPLAN_D_MT7620, 0);
 	rt2800_rfcsr_write(rt2x00dev, 22, rfcsr);
 
@@ -3222,40 +3231,40 @@  static void rt2800_config_channel_rf7620(struct rt2x00_dev *rt2x00dev,
 	 *      R18<7:0> in rf->rf3
 	 *      R19<1:0> in rf->rf4
 	 */
-	rt2800_rfcsr_read(rt2x00dev, 17, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 17);
 	rfcsr = rf->rf2;
 	rt2800_rfcsr_write(rt2x00dev, 17, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 18, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 18);
 	rfcsr = rf->rf3;
 	rt2800_rfcsr_write(rt2x00dev, 18, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 19, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 19);
 	rt2x00_set_field8(&rfcsr, RFCSR19_K, rf->rf4);
 	rt2800_rfcsr_write(rt2x00dev, 19, rfcsr);
 
 	/* Default: XO=20MHz , SDM mode */
-	rt2800_rfcsr_read(rt2x00dev, 16, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 16);
 	rt2x00_set_field8(&rfcsr, RFCSR16_SDM_MODE_MT7620, 0x80);
 	rt2800_rfcsr_write(rt2x00dev, 16, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 21, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 21);
 	rt2x00_set_field8(&rfcsr, RFCSR21_BIT8, 1);
 	rt2800_rfcsr_write(rt2x00dev, 21, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 1, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 1);
 	rt2x00_set_field8(&rfcsr, RFCSR1_TX2_EN_MT7620,
 			  rt2x00dev->default_ant.tx_chain_num != 1);
 	rt2800_rfcsr_write(rt2x00dev, 1, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 2, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 2);
 	rt2x00_set_field8(&rfcsr, RFCSR2_TX2_EN_MT7620,
 			  rt2x00dev->default_ant.tx_chain_num != 1);
 	rt2x00_set_field8(&rfcsr, RFCSR2_RX2_EN_MT7620,
 			  rt2x00dev->default_ant.rx_chain_num != 1);
 	rt2800_rfcsr_write(rt2x00dev, 2, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 42, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 42);
 	rt2x00_set_field8(&rfcsr, RFCSR42_TX2_EN_MT7620,
 			  rt2x00dev->default_ant.tx_chain_num != 1);
 	rt2800_rfcsr_write(rt2x00dev, 42, rfcsr);
@@ -3283,7 +3292,7 @@  static void rt2800_config_channel_rf7620(struct rt2x00_dev *rt2x00dev,
 		rt2800_rfcsr_write_dccal(rt2x00dev, 59, 0x28);
 	}
 
-	rt2800_rfcsr_read(rt2x00dev, 28, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 28);
 	rt2x00_set_field8(&rfcsr, RFCSR28_CH11_HT40,
 			  conf_is_ht40(conf) && (rf->channel == 11));
 	rt2800_rfcsr_write(rt2x00dev, 28, rfcsr);
@@ -3296,36 +3305,36 @@  static void rt2800_config_channel_rf7620(struct rt2x00_dev *rt2x00dev,
 			rx_agc_fc = drv_data->rx_calibration_bw20;
 			tx_agc_fc = drv_data->tx_calibration_bw20;
 		}
-		rt2800_rfcsr_read_bank(rt2x00dev, 5, 6, &rfcsr);
+		rfcsr = rt2800_rfcsr_read_bank(rt2x00dev, 5, 6);
 		rfcsr &= (~0x3F);
 		rfcsr |= rx_agc_fc;
 		rt2800_rfcsr_write_bank(rt2x00dev, 5, 6, rfcsr);
-		rt2800_rfcsr_read_bank(rt2x00dev, 5, 7, &rfcsr);
+		rfcsr = rt2800_rfcsr_read_bank(rt2x00dev, 5, 7);
 		rfcsr &= (~0x3F);
 		rfcsr |= rx_agc_fc;
 		rt2800_rfcsr_write_bank(rt2x00dev, 5, 7, rfcsr);
-		rt2800_rfcsr_read_bank(rt2x00dev, 7, 6, &rfcsr);
+		rfcsr = rt2800_rfcsr_read_bank(rt2x00dev, 7, 6);
 		rfcsr &= (~0x3F);
 		rfcsr |= rx_agc_fc;
 		rt2800_rfcsr_write_bank(rt2x00dev, 7, 6, rfcsr);
-		rt2800_rfcsr_read_bank(rt2x00dev, 7, 7, &rfcsr);
+		rfcsr = rt2800_rfcsr_read_bank(rt2x00dev, 7, 7);
 		rfcsr &= (~0x3F);
 		rfcsr |= rx_agc_fc;
 		rt2800_rfcsr_write_bank(rt2x00dev, 7, 7, rfcsr);
 
-		rt2800_rfcsr_read_bank(rt2x00dev, 5, 58, &rfcsr);
+		rfcsr = rt2800_rfcsr_read_bank(rt2x00dev, 5, 58);
 		rfcsr &= (~0x3F);
 		rfcsr |= tx_agc_fc;
 		rt2800_rfcsr_write_bank(rt2x00dev, 5, 58, rfcsr);
-		rt2800_rfcsr_read_bank(rt2x00dev, 5, 59, &rfcsr);
+		rfcsr = rt2800_rfcsr_read_bank(rt2x00dev, 5, 59);
 		rfcsr &= (~0x3F);
 		rfcsr |= tx_agc_fc;
 		rt2800_rfcsr_write_bank(rt2x00dev, 5, 59, rfcsr);
-		rt2800_rfcsr_read_bank(rt2x00dev, 7, 58, &rfcsr);
+		rfcsr = rt2800_rfcsr_read_bank(rt2x00dev, 7, 58);
 		rfcsr &= (~0x3F);
 		rfcsr |= tx_agc_fc;
 		rt2800_rfcsr_write_bank(rt2x00dev, 7, 58, rfcsr);
-		rt2800_rfcsr_read_bank(rt2x00dev, 7, 59, &rfcsr);
+		rfcsr = rt2800_rfcsr_read_bank(rt2x00dev, 7, 59);
 		rfcsr &= (~0x3F);
 		rfcsr |= tx_agc_fc;
 		rt2800_rfcsr_write_bank(rt2x00dev, 7, 59, rfcsr);
@@ -3597,7 +3606,7 @@  static void rt2800_config_channel(struct rt2x00_dev *rt2x00dev,
 	    rt2x00_rf(rt2x00dev, RF5372) ||
 	    rt2x00_rf(rt2x00dev, RF5390) ||
 	    rt2x00_rf(rt2x00dev, RF5392)) {
-		rt2800_rfcsr_read(rt2x00dev, 30, &rfcsr);
+		rfcsr = rt2800_rfcsr_read(rt2x00dev, 30);
 		if (rt2x00_rf(rt2x00dev, RF3322)) {
 			rt2x00_set_field8(&rfcsr, RF3322_RFCSR30_TX_H20M,
 					  conf_is_ht40(conf));
@@ -3611,7 +3620,7 @@  static void rt2800_config_channel(struct rt2x00_dev *rt2x00dev,
 		}
 		rt2800_rfcsr_write(rt2x00dev, 30, rfcsr);
 
-		rt2800_rfcsr_read(rt2x00dev, 3, &rfcsr);
+		rfcsr = rt2800_rfcsr_read(rt2x00dev, 3);
 		rt2x00_set_field8(&rfcsr, RFCSR3_VCOCAL_EN, 1);
 		rt2800_rfcsr_write(rt2x00dev, 3, rfcsr);
 	}
@@ -4864,7 +4873,7 @@  void rt2800_vco_calibration(struct rt2x00_dev *rt2x00dev)
 	case RF3022:
 	case RF3320:
 	case RF3052:
-		rt2800_rfcsr_read(rt2x00dev, 7, &rfcsr);
+		rfcsr = rt2800_rfcsr_read(rt2x00dev, 7);
 		rt2x00_set_field8(&rfcsr, RFCSR7_RF_TUNING, 1);
 		rt2800_rfcsr_write(rt2x00dev, 7, rfcsr);
 		break;
@@ -4879,7 +4888,7 @@  void rt2800_vco_calibration(struct rt2x00_dev *rt2x00dev)
 	case RF5390:
 	case RF5392:
 	case RF5592:
-		rt2800_rfcsr_read(rt2x00dev, 3, &rfcsr);
+		rfcsr = rt2800_rfcsr_read(rt2x00dev, 3);
 		rt2x00_set_field8(&rfcsr, RFCSR3_VCOCAL_EN, 1);
 		rt2800_rfcsr_write(rt2x00dev, 3, rfcsr);
 		min_sleep = 1000;
@@ -4887,7 +4896,7 @@  void rt2800_vco_calibration(struct rt2x00_dev *rt2x00dev)
 	case RF7620:
 		rt2800_rfcsr_write(rt2x00dev, 5, 0x40);
 		rt2800_rfcsr_write(rt2x00dev, 4, 0x0C);
-		rt2800_rfcsr_read(rt2x00dev, 4, &rfcsr);
+		rfcsr = rt2800_rfcsr_read(rt2x00dev, 4);
 		rt2x00_set_field8(&rfcsr, RFCSR4_VCOCAL_EN, 1);
 		rt2800_rfcsr_write(rt2x00dev, 4, rfcsr);
 		min_sleep = 2000;
@@ -6615,11 +6624,11 @@  static u8 rt2800_init_rx_filter(struct rt2x00_dev *rt2x00dev, bool bw40,
 	rt2x00_set_field8(&bbp, BBP4_BANDWIDTH, 2 * bw40);
 	rt2800_bbp_write(rt2x00dev, 4, bbp);
 
-	rt2800_rfcsr_read(rt2x00dev, 31, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 31);
 	rt2x00_set_field8(&rfcsr, RFCSR31_RX_H20M, bw40);
 	rt2800_rfcsr_write(rt2x00dev, 31, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 22, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 22);
 	rt2x00_set_field8(&rfcsr, RFCSR22_BASEBAND_LOOPBACK, 1);
 	rt2800_rfcsr_write(rt2x00dev, 22, rfcsr);
 
@@ -6668,7 +6677,7 @@  static void rt2800_rf_init_calibration(struct rt2x00_dev *rt2x00dev,
 {
 	u8 rfcsr;
 
-	rt2800_rfcsr_read(rt2x00dev, rf_reg, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, rf_reg);
 	rt2x00_set_field8(&rfcsr, FIELD8(0x80), 1);
 	rt2800_rfcsr_write(rt2x00dev, rf_reg, rfcsr);
 	msleep(1);
@@ -6710,7 +6719,7 @@  static void rt2800_rx_filter_calibration(struct rt2x00_dev *rt2x00dev)
 	 */
 	rt2800_bbp_write(rt2x00dev, 24, 0);
 
-	rt2800_rfcsr_read(rt2x00dev, 22, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 22);
 	rt2x00_set_field8(&rfcsr, RFCSR22_BASEBAND_LOOPBACK, 0);
 	rt2800_rfcsr_write(rt2x00dev, 22, rfcsr);
 
@@ -6728,7 +6737,7 @@  static void rt2800_normal_mode_setup_3xxx(struct rt2x00_dev *rt2x00dev)
 	u8 min_gain, rfcsr, bbp;
 	u16 eeprom;
 
-	rt2800_rfcsr_read(rt2x00dev, 17, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 17);
 
 	rt2x00_set_field8(&rfcsr, RFCSR17_TX_LO1_EN, 0);
 	if (rt2x00_rt(rt2x00dev, RT3070) ||
@@ -6759,7 +6768,7 @@  static void rt2800_normal_mode_setup_3xxx(struct rt2x00_dev *rt2x00dev)
 	}
 
 	if (rt2x00_rt(rt2x00dev, RT3070)) {
-		rt2800_rfcsr_read(rt2x00dev, 27, &rfcsr);
+		rfcsr = rt2800_rfcsr_read(rt2x00dev, 27);
 		if (rt2x00_rt_rev_lt(rt2x00dev, RT3070, REV_RT3070F))
 			rt2x00_set_field8(&rfcsr, RFCSR27_R1, 3);
 		else
@@ -6771,7 +6780,7 @@  static void rt2800_normal_mode_setup_3xxx(struct rt2x00_dev *rt2x00dev)
 	} else if (rt2x00_rt(rt2x00dev, RT3071) ||
 		   rt2x00_rt(rt2x00dev, RT3090) ||
 		   rt2x00_rt(rt2x00dev, RT3390)) {
-		rt2800_rfcsr_read(rt2x00dev, 1, &rfcsr);
+		rfcsr = rt2800_rfcsr_read(rt2x00dev, 1);
 		rt2x00_set_field8(&rfcsr, RFCSR1_RF_BLOCK_EN, 1);
 		rt2x00_set_field8(&rfcsr, RFCSR1_RX0_PD, 0);
 		rt2x00_set_field8(&rfcsr, RFCSR1_TX0_PD, 0);
@@ -6779,15 +6788,15 @@  static void rt2800_normal_mode_setup_3xxx(struct rt2x00_dev *rt2x00dev)
 		rt2x00_set_field8(&rfcsr, RFCSR1_TX1_PD, 1);
 		rt2800_rfcsr_write(rt2x00dev, 1, rfcsr);
 
-		rt2800_rfcsr_read(rt2x00dev, 15, &rfcsr);
+		rfcsr = rt2800_rfcsr_read(rt2x00dev, 15);
 		rt2x00_set_field8(&rfcsr, RFCSR15_TX_LO2_EN, 0);
 		rt2800_rfcsr_write(rt2x00dev, 15, rfcsr);
 
-		rt2800_rfcsr_read(rt2x00dev, 20, &rfcsr);
+		rfcsr = rt2800_rfcsr_read(rt2x00dev, 20);
 		rt2x00_set_field8(&rfcsr, RFCSR20_RX_LO1_EN, 0);
 		rt2800_rfcsr_write(rt2x00dev, 20, rfcsr);
 
-		rt2800_rfcsr_read(rt2x00dev, 21, &rfcsr);
+		rfcsr = rt2800_rfcsr_read(rt2x00dev, 21);
 		rt2x00_set_field8(&rfcsr, RFCSR21_RX_LO2_EN, 0);
 		rt2800_rfcsr_write(rt2x00dev, 21, rfcsr);
 	}
@@ -6799,30 +6808,30 @@  static void rt2800_normal_mode_setup_3593(struct rt2x00_dev *rt2x00dev)
 	u8 rfcsr;
 	u8 tx_gain;
 
-	rt2800_rfcsr_read(rt2x00dev, 50, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 50);
 	rt2x00_set_field8(&rfcsr, RFCSR50_TX_LO2_EN, 0);
 	rt2800_rfcsr_write(rt2x00dev, 50, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 51, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 51);
 	tx_gain = rt2x00_get_field8(drv_data->txmixer_gain_24g,
 				    RFCSR17_TXMIXER_GAIN);
 	rt2x00_set_field8(&rfcsr, RFCSR51_BITS24, tx_gain);
 	rt2800_rfcsr_write(rt2x00dev, 51, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 38, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 38);
 	rt2x00_set_field8(&rfcsr, RFCSR38_RX_LO1_EN, 0);
 	rt2800_rfcsr_write(rt2x00dev, 38, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 39, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 39);
 	rt2x00_set_field8(&rfcsr, RFCSR39_RX_LO2_EN, 0);
 	rt2800_rfcsr_write(rt2x00dev, 39, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 1, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 1);
 	rt2x00_set_field8(&rfcsr, RFCSR1_RF_BLOCK_EN, 1);
 	rt2x00_set_field8(&rfcsr, RFCSR1_PLL_PD, 1);
 	rt2800_rfcsr_write(rt2x00dev, 1, rfcsr);
 
-	rt2800_rfcsr_read(rt2x00dev, 30, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 30);
 	rt2x00_set_field8(&rfcsr, RFCSR30_RX_VCM, 2);
 	rt2800_rfcsr_write(rt2x00dev, 30, rfcsr);
 
@@ -6843,17 +6852,17 @@  static void rt2800_normal_mode_setup_5xxx(struct rt2x00_dev *rt2x00dev)
 		rt2x00_set_field8(&reg, BBP138_TX_DAC1, 1);
 	rt2800_bbp_write(rt2x00dev, 138, reg);
 
-	rt2800_rfcsr_read(rt2x00dev, 38, &reg);
+	reg = rt2800_rfcsr_read(rt2x00dev, 38);
 	rt2x00_set_field8(&reg, RFCSR38_RX_LO1_EN, 0);
 	rt2800_rfcsr_write(rt2x00dev, 38, reg);
 
-	rt2800_rfcsr_read(rt2x00dev, 39, &reg);
+	reg = rt2800_rfcsr_read(rt2x00dev, 39);
 	rt2x00_set_field8(&reg, RFCSR39_RX_LO2_EN, 0);
 	rt2800_rfcsr_write(rt2x00dev, 39, reg);
 
 	rt2800_bbp4_mac_if_ctrl(rt2x00dev);
 
-	rt2800_rfcsr_read(rt2x00dev, 30, &reg);
+	reg = rt2800_rfcsr_read(rt2x00dev, 30);
 	rt2x00_set_field8(&reg, RFCSR30_RX_VCM, 2);
 	rt2800_rfcsr_write(rt2x00dev, 30, reg);
 }
@@ -6934,7 +6943,7 @@  static void rt2800_init_rfcsr_30xx(struct rt2x00_dev *rt2x00dev)
 		   rt2x00_rt(rt2x00dev, RT3090)) {
 		rt2800_rfcsr_write(rt2x00dev, 31, 0x14);
 
-		rt2800_rfcsr_read(rt2x00dev, 6, &rfcsr);
+		rfcsr = rt2800_rfcsr_read(rt2x00dev, 6);
 		rt2x00_set_field8(&rfcsr, RFCSR6_R2, 1);
 		rt2800_rfcsr_write(rt2x00dev, 6, rfcsr);
 
@@ -7020,7 +7029,7 @@  static void rt2800_init_rfcsr_3290(struct rt2x00_dev *rt2x00dev)
 	rt2800_rfcsr_write(rt2x00dev, 60, 0x45);
 	rt2800_rfcsr_write(rt2x00dev, 61, 0xc1);
 
-	rt2800_rfcsr_read(rt2x00dev, 29, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 29);
 	rt2x00_set_field8(&rfcsr, RFCSR29_RSSI_GAIN, 3);
 	rt2800_rfcsr_write(rt2x00dev, 29, rfcsr);
 
@@ -7218,7 +7227,7 @@  static void rt2800_init_rfcsr_3572(struct rt2x00_dev *rt2x00dev)
 	rt2800_rfcsr_write(rt2x00dev, 30, 0x09);
 	rt2800_rfcsr_write(rt2x00dev, 31, 0x10);
 
-	rt2800_rfcsr_read(rt2x00dev, 6, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 6);
 	rt2x00_set_field8(&rfcsr, RFCSR6_R2, 1);
 	rt2800_rfcsr_write(rt2x00dev, 6, rfcsr);
 
@@ -7332,13 +7341,13 @@  static void rt2800_init_rfcsr_3593(struct rt2x00_dev *rt2x00dev)
 
 	/* Initiate calibration */
 	/* TODO: use rt2800_rf_init_calibration ? */
-	rt2800_rfcsr_read(rt2x00dev, 2, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 2);
 	rt2x00_set_field8(&rfcsr, RFCSR2_RESCAL_EN, 1);
 	rt2800_rfcsr_write(rt2x00dev, 2, rfcsr);
 
 	rt2800_freq_cal_mode1(rt2x00dev);
 
-	rt2800_rfcsr_read(rt2x00dev, 18, &rfcsr);
+	rfcsr = rt2800_rfcsr_read(rt2x00dev, 18);
 	rt2x00_set_field8(&rfcsr, RFCSR18_XO_TUNE_BYPASS, 1);
 	rt2800_rfcsr_write(rt2x00dev, 18, rfcsr);
 
@@ -7680,7 +7689,7 @@  static int rt2800_rf_lp_config(struct rt2x00_dev *rt2x00dev, bool btxcal)
 
 	rt2800_register_write(rt2x00dev, RF_BYPASS0, 0x06);
 
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 17, &rf_val);
+	rf_val = rt2800_rfcsr_read_bank(rt2x00dev, 5, 17);
 	rf_val |= 0x80;
 	rt2800_rfcsr_write_bank(rt2x00dev, 5, 17, rf_val);
 
@@ -7688,11 +7697,11 @@  static int rt2800_rf_lp_config(struct rt2x00_dev *rt2x00dev, bool btxcal)
 		rt2800_rfcsr_write_bank(rt2x00dev, 5, 18, 0xC1);
 		rt2800_rfcsr_write_bank(rt2x00dev, 5, 19, 0x20);
 		rt2800_rfcsr_write_bank(rt2x00dev, 5, 20, 0x02);
-		rt2800_rfcsr_read_bank(rt2x00dev, 5, 3, &rf_val);
+		rf_val = rt2800_rfcsr_read_bank(rt2x00dev, 5, 3);
 		rf_val &= (~0x3F);
 		rf_val |= 0x3F;
 		rt2800_rfcsr_write_bank(rt2x00dev, 5, 3, rf_val);
-		rt2800_rfcsr_read_bank(rt2x00dev, 5, 4, &rf_val);
+		rf_val = rt2800_rfcsr_read_bank(rt2x00dev, 5, 4);
 		rf_val &= (~0x3F);
 		rf_val |= 0x3F;
 		rt2800_rfcsr_write_bank(rt2x00dev, 5, 4, rf_val);
@@ -7701,11 +7710,11 @@  static int rt2800_rf_lp_config(struct rt2x00_dev *rt2x00dev, bool btxcal)
 		rt2800_rfcsr_write_bank(rt2x00dev, 5, 18, 0xF1);
 		rt2800_rfcsr_write_bank(rt2x00dev, 5, 19, 0x18);
 		rt2800_rfcsr_write_bank(rt2x00dev, 5, 20, 0x02);
-		rt2800_rfcsr_read_bank(rt2x00dev, 5, 3, &rf_val);
+		rf_val = rt2800_rfcsr_read_bank(rt2x00dev, 5, 3);
 		rf_val &= (~0x3F);
 		rf_val |= 0x34;
 		rt2800_rfcsr_write_bank(rt2x00dev, 5, 3, rf_val);
-		rt2800_rfcsr_read_bank(rt2x00dev, 5, 4, &rf_val);
+		rf_val = rt2800_rfcsr_read_bank(rt2x00dev, 5, 4);
 		rf_val &= (~0x3F);
 		rf_val |= 0x34;
 		rt2800_rfcsr_write_bank(rt2x00dev, 5, 4, rf_val);
@@ -7771,51 +7780,51 @@  static void rt2800_bw_filter_calibration(struct rt2x00_dev *rt2x00dev,
 	rt2800_bbp_dcoc_read(rt2x00dev, 2, &savebbp159r2);
 
 	/* Save RF registers */
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 0, &saverfb5r00);
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 1, &saverfb5r01);
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 3, &saverfb5r03);
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 4, &saverfb5r04);
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 5, &saverfb5r05);
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 6, &saverfb5r06);
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 7, &saverfb5r07);
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 8, &saverfb5r08);
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 17, &saverfb5r17);
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 18, &saverfb5r18);
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 19, &saverfb5r19);
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 20, &saverfb5r20);
-
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 37, &saverfb5r37);
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 38, &saverfb5r38);
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 39, &saverfb5r39);
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 40, &saverfb5r40);
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 41, &saverfb5r41);
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 42, &saverfb5r42);
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 43, &saverfb5r43);
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 44, &saverfb5r44);
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 45, &saverfb5r45);
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 46, &saverfb5r46);
-
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 58, &saverfb5r58);
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 59, &saverfb5r59);
-
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 0, &rf_val);
+	saverfb5r00 = rt2800_rfcsr_read_bank(rt2x00dev, 5, 0);
+	saverfb5r01 = rt2800_rfcsr_read_bank(rt2x00dev, 5, 1);
+	saverfb5r03 = rt2800_rfcsr_read_bank(rt2x00dev, 5, 3);
+	saverfb5r04 = rt2800_rfcsr_read_bank(rt2x00dev, 5, 4);
+	saverfb5r05 = rt2800_rfcsr_read_bank(rt2x00dev, 5, 5);
+	saverfb5r06 = rt2800_rfcsr_read_bank(rt2x00dev, 5, 6);
+	saverfb5r07 = rt2800_rfcsr_read_bank(rt2x00dev, 5, 7);
+	saverfb5r08 = rt2800_rfcsr_read_bank(rt2x00dev, 5, 8);
+	saverfb5r17 = rt2800_rfcsr_read_bank(rt2x00dev, 5, 17);
+	saverfb5r18 = rt2800_rfcsr_read_bank(rt2x00dev, 5, 18);
+	saverfb5r19 = rt2800_rfcsr_read_bank(rt2x00dev, 5, 19);
+	saverfb5r20 = rt2800_rfcsr_read_bank(rt2x00dev, 5, 20);
+
+	saverfb5r37 = rt2800_rfcsr_read_bank(rt2x00dev, 5, 37);
+	saverfb5r38 = rt2800_rfcsr_read_bank(rt2x00dev, 5, 38);
+	saverfb5r39 = rt2800_rfcsr_read_bank(rt2x00dev, 5, 39);
+	saverfb5r40 = rt2800_rfcsr_read_bank(rt2x00dev, 5, 40);
+	saverfb5r41 = rt2800_rfcsr_read_bank(rt2x00dev, 5, 41);
+	saverfb5r42 = rt2800_rfcsr_read_bank(rt2x00dev, 5, 42);
+	saverfb5r43 = rt2800_rfcsr_read_bank(rt2x00dev, 5, 43);
+	saverfb5r44 = rt2800_rfcsr_read_bank(rt2x00dev, 5, 44);
+	saverfb5r45 = rt2800_rfcsr_read_bank(rt2x00dev, 5, 45);
+	saverfb5r46 = rt2800_rfcsr_read_bank(rt2x00dev, 5, 46);
+
+	saverfb5r58 = rt2800_rfcsr_read_bank(rt2x00dev, 5, 58);
+	saverfb5r59 = rt2800_rfcsr_read_bank(rt2x00dev, 5, 59);
+
+	rf_val = rt2800_rfcsr_read_bank(rt2x00dev, 5, 0);
 	rf_val |= 0x3;
 	rt2800_rfcsr_write_bank(rt2x00dev, 5, 0, rf_val);
 
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 1, &rf_val);
+	rf_val = rt2800_rfcsr_read_bank(rt2x00dev, 5, 1);
 	rf_val |= 0x1;
 	rt2800_rfcsr_write_bank(rt2x00dev, 5, 1, rf_val);
 
 	cnt = 0;
 	do {
 		usleep_range(500, 2000);
-		rt2800_rfcsr_read_bank(rt2x00dev, 5, 1, &rf_val);
+		rf_val = rt2800_rfcsr_read_bank(rt2x00dev, 5, 1);
 		if (((rf_val & 0x1) == 0x00) || (cnt == 40))
 			break;
 		cnt++;
 	} while (cnt < 40);
 
-	rt2800_rfcsr_read_bank(rt2x00dev, 5, 0, &rf_val);
+	rf_val = rt2800_rfcsr_read_bank(rt2x00dev, 5, 0);
 	rf_val &= (~0x3);
 	rf_val |= 0x1;
 	rt2800_rfcsr_write_bank(rt2x00dev, 5, 0, rf_val);
@@ -7844,7 +7853,7 @@  static void rt2800_bw_filter_calibration(struct rt2x00_dev *rt2x00dev,
 				filter_target = rx_filter_target_40m;
 		}
 
-		rt2800_rfcsr_read_bank(rt2x00dev, 5, 8, &rf_val);
+		rf_val = rt2800_rfcsr_read_bank(rt2x00dev, 5, 8);
 		rf_val &= (~0x04);
 		if (loop == 1)
 			rf_val |= 0x4;
@@ -7856,18 +7865,18 @@  static void rt2800_bw_filter_calibration(struct rt2x00_dev *rt2x00dev,
 		rt2800_rf_lp_config(rt2x00dev, btxcal);
 		if (btxcal) {
 			tx_agc_fc = 0;
-			rt2800_rfcsr_read_bank(rt2x00dev, 5, 58, &rf_val);
+			rf_val = rt2800_rfcsr_read_bank(rt2x00dev, 5, 58);
 			rf_val &= (~0x7F);
 			rt2800_rfcsr_write_bank(rt2x00dev, 5, 58, rf_val);
-			rt2800_rfcsr_read_bank(rt2x00dev, 5, 59, &rf_val);
+			rf_val = rt2800_rfcsr_read_bank(rt2x00dev, 5, 59);
 			rf_val &= (~0x7F);
 			rt2800_rfcsr_write_bank(rt2x00dev, 5, 59, rf_val);
 		} else {
 			rx_agc_fc = 0;
-			rt2800_rfcsr_read_bank(rt2x00dev, 5, 6, &rf_val);
+			rf_val = rt2800_rfcsr_read_bank(rt2x00dev, 5, 6);
 			rf_val &= (~0x7F);
 			rt2800_rfcsr_write_bank(rt2x00dev, 5, 6, rf_val);
-			rt2800_rfcsr_read_bank(rt2x00dev, 5, 7, &rf_val);
+			rf_val = rt2800_rfcsr_read_bank(rt2x00dev, 5, 7);
 			rf_val &= (~0x7F);
 			rt2800_rfcsr_write_bank(rt2x00dev, 5, 7, rf_val);
 		}
@@ -7887,20 +7896,20 @@  static void rt2800_bw_filter_calibration(struct rt2x00_dev *rt2x00dev,
 		rt2800_bbp_dcoc_write(rt2x00dev, 2, bbp_val);
 do_cal:
 		if (btxcal) {
-			rt2800_rfcsr_read_bank(rt2x00dev, 5, 58, &rf_val);
+			rf_val = rt2800_rfcsr_read_bank(rt2x00dev, 5, 58);
 			rf_val &= (~0x7F);
 			rf_val |= tx_agc_fc;
 			rt2800_rfcsr_write_bank(rt2x00dev, 5, 58, rf_val);
-			rt2800_rfcsr_read_bank(rt2x00dev, 5, 59, &rf_val);
+			rf_val = rt2800_rfcsr_read_bank(rt2x00dev, 5, 59);
 			rf_val &= (~0x7F);
 			rf_val |= tx_agc_fc;
 			rt2800_rfcsr_write_bank(rt2x00dev, 5, 59, rf_val);
 		} else {
-			rt2800_rfcsr_read_bank(rt2x00dev, 5, 6, &rf_val);
+			rf_val = rt2800_rfcsr_read_bank(rt2x00dev, 5, 6);
 			rf_val &= (~0x7F);
 			rf_val |= rx_agc_fc;
 			rt2800_rfcsr_write_bank(rt2x00dev, 5, 6, rf_val);
-			rt2800_rfcsr_read_bank(rt2x00dev, 5, 7, &rf_val);
+			rf_val = rt2800_rfcsr_read_bank(rt2x00dev, 5, 7);
 			rf_val &= (~0x7F);
 			rf_val |= rx_agc_fc;
 			rt2800_rfcsr_write_bank(rt2x00dev, 5, 7, rf_val);