diff mbox series

[02/10] mfd: rt5033: Fix chip revision readout

Message ID a667a64d0cbeef00baed2d4b117ba9f50eaf3988.1677620677.git.jahau@rocketmail.com
State New
Headers show
Series [01/10] mfd: rt5033: Drop rt5033-battery sub-device | expand

Commit Message

Jakob Hauser Feb. 28, 2023, 10:32 p.m. UTC
After reading the data from the DEVICE_ID register, mask 0x0f needs to be
applied to extract the revision of the chip [1].

The other part of the DEVICE_ID register, mask 0xf0, is a vendor identification
code. That's how it is set up at similar products of Richtek, e.g. RT9455 [2]
page 21 top.

[1] https://github.com/msm8916-mainline/linux-downstream/blob/GT-I9195I/drivers/mfd/rt5033_core.c#L484
[2] https://www.richtek.com/assets/product_file/RT9455/DS9455-00.pdf

Signed-off-by: Jakob Hauser <jahau@rocketmail.com>
---
 drivers/mfd/rt5033.c               | 8 +++++---
 include/linux/mfd/rt5033-private.h | 4 ++++
 2 files changed, 9 insertions(+), 3 deletions(-)

Comments

Jakob Hauser March 6, 2023, 10:57 p.m. UTC | #1
Hi Lee,

On 06.03.23 10:18, Lee Jones wrote:
> On Sun, 05 Mar 2023, Jakob Hauser wrote:
> 
>> Hi Lee,
>>
>> On 05.03.23 11:47, Lee Jones wrote:
>>> On Tue, 28 Feb 2023, Jakob Hauser wrote:
>>>
>>>> After reading the data from the DEVICE_ID register, mask 0x0f needs to be
>>>> applied to extract the revision of the chip [1].
>>>>
>>>> The other part of the DEVICE_ID register, mask 0xf0, is a vendor identification
>>>> code. That's how it is set up at similar products of Richtek, e.g. RT9455 [2]
>>>> page 21 top.
>>>>
>>>> [1] https://github.com/msm8916-mainline/linux-downstream/blob/GT-I9195I/drivers/mfd/rt5033_core.c#L484
>>>> [2] https://www.richtek.com/assets/product_file/RT9455/DS9455-00.pdf
>>>>
>>>> Signed-off-by: Jakob Hauser <jahau@rocketmail.com>
>>>> ---
>>>>    drivers/mfd/rt5033.c               | 8 +++++---
>>>>    include/linux/mfd/rt5033-private.h | 4 ++++
>>>>    2 files changed, 9 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/drivers/mfd/rt5033.c b/drivers/mfd/rt5033.c
>>>> index 8029d444b794..d32467174cb5 100644
>>>> --- a/drivers/mfd/rt5033.c
>>>> +++ b/drivers/mfd/rt5033.c
>>>> @@ -55,7 +55,8 @@ static const struct regmap_config rt5033_regmap_config = {
>>>>    static int rt5033_i2c_probe(struct i2c_client *i2c)
>>>>    {
>>>>    	struct rt5033_dev *rt5033;
>>>> -	unsigned int dev_id;
>>>> +	unsigned int data;
>>>
>>> In terms of nomenclature, this is a regression.
>>>
>>> 'data' is a terrible variable name.  Why not keep it as-is?
>>
>> While not having a datasheet for RT5033 available, in similar products like
>> RT9455 the register is called "Device ID", the first part of that is
>> "VENDOR_ID" and the second part "CHIP_REV", [1] page 23 top. Or in RT5036
>> preliminary data sheet the register is called "ID", the first part
>> "VENDOR_ID" and the second part "CHIP_REV_ID", [2] page 27 top.
>>
>> I wanted to avoid confusion between "dev_id" and "chip_rev". Therefore in
>> the patch it's written as getting some "data" from the register and extract
>> "chip_rev" from that data.
>>
>> I could change it to "reg_data"? Or something in that direction? I still
>> think that getting "chip_rev" out of "dev_id" would be confusing.
> 
> You're reading from a register called RT5033_REG_DEVICE_ID.  I don't see
> any reason why the variable you read into can't reflect that.

OK, I'll use "dev_id" and "chip_rev" for the variable names.

...

Kind regards,
Jakob
diff mbox series

Patch

diff --git a/drivers/mfd/rt5033.c b/drivers/mfd/rt5033.c
index 8029d444b794..d32467174cb5 100644
--- a/drivers/mfd/rt5033.c
+++ b/drivers/mfd/rt5033.c
@@ -55,7 +55,8 @@  static const struct regmap_config rt5033_regmap_config = {
 static int rt5033_i2c_probe(struct i2c_client *i2c)
 {
 	struct rt5033_dev *rt5033;
-	unsigned int dev_id;
+	unsigned int data;
+	unsigned int chip_rev;
 	int ret;
 
 	rt5033 = devm_kzalloc(&i2c->dev, sizeof(*rt5033), GFP_KERNEL);
@@ -73,12 +74,13 @@  static int rt5033_i2c_probe(struct i2c_client *i2c)
 		return PTR_ERR(rt5033->regmap);
 	}
 
-	ret = regmap_read(rt5033->regmap, RT5033_REG_DEVICE_ID, &dev_id);
+	ret = regmap_read(rt5033->regmap, RT5033_REG_DEVICE_ID, &data);
 	if (ret) {
 		dev_err(&i2c->dev, "Device not found\n");
 		return -ENODEV;
 	}
-	dev_info(&i2c->dev, "Device found Device ID: %04x\n", dev_id);
+	chip_rev = data & RT5033_CHIP_REV_MASK;
+	dev_info(&i2c->dev, "Device found (rev. %d)\n", chip_rev);
 
 	ret = regmap_add_irq_chip(rt5033->regmap, rt5033->irq,
 			IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
diff --git a/include/linux/mfd/rt5033-private.h b/include/linux/mfd/rt5033-private.h
index 2d1895c3efbf..d18cd4572208 100644
--- a/include/linux/mfd/rt5033-private.h
+++ b/include/linux/mfd/rt5033-private.h
@@ -71,6 +71,10 @@  enum rt5033_reg {
 /* RT5033 CHGCTRL2 register */
 #define RT5033_CHGCTRL2_CV_MASK		0xfc
 
+/* RT5033 DEVICE_ID register */
+#define RT5033_VENDOR_ID_MASK		0xf0
+#define RT5033_CHIP_REV_MASK		0x0f
+
 /* RT5033 CHGCTRL3 register */
 #define RT5033_CHGCTRL3_CFO_EN_MASK	0x40
 #define RT5033_CHGCTRL3_TIMER_MASK	0x38