diff mbox

[v3,2/6] pinctrl: Introduce pinctrl driver for Qualcomm SSBI PMIC's

Message ID 53F456F3.3000309@linaro.org
State New
Headers show

Commit Message

Srinivas Kandagatla Aug. 20, 2014, 8:06 a.m. UTC
Hi Bjorn,

Two things which I noticed while trying out this driver to drive a reset 
line.

1> gpio numbering for pinconf vs gpio are not consistent, they differ by 
an offset of 1.

For example to control GPIO43 I had to do something like this in pinconf:

wlan_default_gpios: wlan-gpios {
	pios {
		pins = "gpio43";
		function = "normal";
		bias-disable;
		power-source = <PM8921_GPIO_S4>;
	};
};


for same pin for gpio I had to do:
	reset-gpio = <&pm8921_gpio 42 GPIO_ACTIVE_LOW>;

This offset by 1 is bit confusing and can easily lead to errors which 
are hard to find.

I think this should be easy to fix..

2> Looking back at v3.4 kernel, for gpio modes, BIT(0) of bank 0 is set 
to enable gpio mode. without this bit driver does not work for output pins.

here is the patch which fixes this:

 From 5a5c5171a3371cf38ccd157922ea140bfd0253d5 Mon Sep 17 00:00:00 2001
From: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Date: Wed, 20 Aug 2014 07:18:03 +0100
Subject: [PATCH] pinctrl:qcom:ssbi: Enable gpio mode

Looking back at 3.4 kernel driver, it looks like the gpio enable bit is
missing in this driver.

This patch is just a hack to get the wlan reset line working.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
---
  drivers/pinctrl/qcom/pinctrl-ssbi-pmic.c | 4 +++-
  1 file changed, 3 insertions(+), 1 deletion(-)

  		val = pin->direction << 2;

Comments

Bjorn Andersson Aug. 20, 2014, 9:28 p.m. UTC | #1
On Wed 20 Aug 01:06 PDT 2014, Srinivas Kandagatla wrote:

> Hi Bjorn,
> 

Hi Srinivas,

Thanks for the testing. I'm reworking the driver to incorporate yours, Linus'
and Ivans feedback.

> Two things which I noticed while trying out this driver to drive a reset
> line.
> 
> 1> gpio numbering for pinconf vs gpio are not consistent, they differ by
> an offset of 1.
> 

After scratching my head regarding this I now see that there's a off by one in
most of the gpio functions. I've rewroked this to make more sense now.

The gpio numbers has to start at 1, as all documentation is based on that.

[...]
> 
> 2> Looking back at v3.4 kernel, for gpio modes, BIT(0) of bank 0 is set
> to enable gpio mode. without this bit driver does not work for output pins.
> 

Thanks, I missed that.

Unfortunately, setting that bit results in input not working - the interrupt
bits are never set for gpios that have that bit set. I'm trying to figure out
why this is the case before sending out the new version...

Regards,
Bjorn
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Bjorn Andersson Aug. 20, 2014, 10:13 p.m. UTC | #2
On Wed, Aug 20, 2014 at 2:28 PM, Bjorn Andersson
<bjorn.andersson@sonymobile.com> wrote:
> On Wed 20 Aug 01:06 PDT 2014, Srinivas Kandagatla wrote:
>> 2> Looking back at v3.4 kernel, for gpio modes, BIT(0) of bank 0 is set
>> to enable gpio mode. without this bit driver does not work for output pins.
>>
>
> Thanks, I missed that.
>
> Unfortunately, setting that bit results in input not working - the interrupt
> bits are never set for gpios that have that bit set. I'm trying to figure out
> why this is the case before sending out the new version...

With help from Andy Gross this is now corrected as well, turned out
that BIT(0) in bank0 controls if the "direction" is considered. As I
was tricked by the multiple levels of indirection in the codeaurora
version I got these wrong.

Will send out an updated version shortly.

Regards,
Bjorn
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Srinivas Kandagatla Nov. 3, 2014, 8:48 a.m. UTC | #3
Hi Bjorn,

On 20/08/14 23:13, Bjorn Andersson wrote:
> On Wed, Aug 20, 2014 at 2:28 PM, Bjorn Andersson
> <bjorn.andersson@sonymobile.com> wrote:
>> On Wed 20 Aug 01:06 PDT 2014, Srinivas Kandagatla wrote:
>>> 2> Looking back at v3.4 kernel, for gpio modes, BIT(0) of bank 0 is set
>>> to enable gpio mode. without this bit driver does not work for output pins.
>>>
>>
>> Thanks, I missed that.
>>
>> Unfortunately, setting that bit results in input not working - the interrupt
>> bits are never set for gpios that have that bit set. I'm trying to figure out
>> why this is the case before sending out the new version...
>
> With help from Andy Gross this is now corrected as well, turned out
> that BIT(0) in bank0 controls if the "direction" is considered. As I
> was tricked by the multiple levels of indirection in the codeaurora
> version I got these wrong.
>
> Will send out an updated version shortly.
Did you get a chance to spin a new version of this patcheset?

--srini
>
> Regards,
> Bjorn
>
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Bjorn Andersson Nov. 4, 2014, 2:25 a.m. UTC | #4
On Mon 03 Nov 00:48 PST 2014, Srinivas Kandagatla wrote:

> Hi Bjorn,
> 
> On 20/08/14 23:13, Bjorn Andersson wrote:
> > On Wed, Aug 20, 2014 at 2:28 PM, Bjorn Andersson
> > <bjorn.andersson@sonymobile.com> wrote:
> >> On Wed 20 Aug 01:06 PDT 2014, Srinivas Kandagatla wrote:
> >>> 2> Looking back at v3.4 kernel, for gpio modes, BIT(0) of bank 0 is set
> >>> to enable gpio mode. without this bit driver does not work for output pins.
> >>>
> >>
> >> Thanks, I missed that.
> >>
> >> Unfortunately, setting that bit results in input not working - the interrupt
> >> bits are never set for gpios that have that bit set. I'm trying to figure out
> >> why this is the case before sending out the new version...
> >
> > With help from Andy Gross this is now corrected as well, turned out
> > that BIT(0) in bank0 controls if the "direction" is considered. As I
> > was tricked by the multiple levels of indirection in the codeaurora
> > version I got these wrong.
> >
> > Will send out an updated version shortly.
> Did you get a chance to spin a new version of this patcheset?
> 

Hi Srini,

Unfortunately it ended up on my todo list waiting for a discussion on
irq_read_line(). As this seems to fall in place I will try to get this updated
and sent out.

Sorry for the delays.

Regards,
Bjorn
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diff mbox

Patch

diff --git a/drivers/pinctrl/qcom/pinctrl-ssbi-pmic.c 
b/drivers/pinctrl/qcom/pinctrl-ssbi-pmic.c
index 27e5ec9..2633ea1 100644
--- a/drivers/pinctrl/qcom/pinctrl-ssbi-pmic.c
+++ b/drivers/pinctrl/qcom/pinctrl-ssbi-pmic.c
@@ -49,6 +49,7 @@ 
  #define SSBI_REG_ADDR_GPIO_BASE		0x150
  #define SSBI_REG_ADDR_GPIO(n)		(SSBI_REG_ADDR_GPIO_BASE + n)

+#define	PM8XXX_GPIO_MODE_ENABLE		BIT(0)
  #define PM8XXX_GPIO_WRITE		BIT(7)

  #define PM8XXX_MAX_GPIOS		44
@@ -493,7 +494,8 @@  static int pm8xxx_gpio_config_set(struct pinctrl_dev 
*pctldev,
  	}

  	if (banks & BIT(0))
-		pm8xxx_gpio_write(pctrl, offset, 0, pin->power_source << 1);
+		pm8xxx_gpio_write(pctrl, offset, 0, pin->power_source << 1 |
+				  PM8XXX_GPIO_MODE_ENABLE);

  	if (banks & BIT(1)) {