diff mbox series

[5/6] platform/x86: int3472/discrete: Ensure the clk/power enable pins are in output mode

Message ID 20221129231149.697154-6-hdegoede@redhat.com (mailing list archive)
State Superseded
Delegated to: Sakari Ailus
Headers
Series ov5693/int3472: Privacy LED handling changes + IPU6 compatibility |

Commit Message

Hans de Goede Nov. 29, 2022, 11:11 p.m. UTC 
  acpi_get_and_request_gpiod() does not take a gpio_lookup_flags argument
specifying that the pins direction should be initialized to a specific
value.

This means that in some cases the pins might be left in input mode, causing
the gpiod_set() calls made to enable the clk / regulator to not work.

One example of this problem is the clk-enable GPIO for the ov01a1s sensor
on a Dell Latitude 9420 being left in input mode causing the clk to
never get enabled.

Explicitly set the direction of the pins to output to fix this.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 drivers/platform/x86/intel/int3472/clk_and_regulator.c | 6 ++++++
 1 file changed, 6 insertions(+)

Comments

Andy Shevchenko Nov. 30, 2022, 9:59 a.m. UTC | #1 
On Wed, Nov 30, 2022 at 1:12 AM Hans de Goede <hdegoede@redhat.com> wrote:
>
> acpi_get_and_request_gpiod() does not take a gpio_lookup_flags argument
> specifying that the pins direction should be initialized to a specific
> value.
>
> This means that in some cases the pins might be left in input mode, causing
> the gpiod_set() calls made to enable the clk / regulator to not work.
>
> One example of this problem is the clk-enable GPIO for the ov01a1s sensor
> on a Dell Latitude 9420 being left in input mode causing the clk to
> never get enabled.
>
> Explicitly set the direction of the pins to output to fix this.

...

> +       /* Ensure the pin is in output mode */

...in output mode and non-active state */

> +       gpiod_direction_output(int3472->clock.ena_gpio, 0);

...

> +       /* Ensure the pin is in output mode */
> +       gpiod_direction_output(int3472->regulator.gpio, 0);

So, previously it was AS IS and now it's non-active state. I believe
this makes no regressions for the other laptops / platforms.
Hans de Goede Nov. 30, 2022, 10:37 a.m. UTC | #2 
Hi,

On 11/30/22 10:59, Andy Shevchenko wrote:
> On Wed, Nov 30, 2022 at 1:12 AM Hans de Goede <hdegoede@redhat.com> wrote:
>>
>> acpi_get_and_request_gpiod() does not take a gpio_lookup_flags argument
>> specifying that the pins direction should be initialized to a specific
>> value.
>>
>> This means that in some cases the pins might be left in input mode, causing
>> the gpiod_set() calls made to enable the clk / regulator to not work.
>>
>> One example of this problem is the clk-enable GPIO for the ov01a1s sensor
>> on a Dell Latitude 9420 being left in input mode causing the clk to
>> never get enabled.
>>
>> Explicitly set the direction of the pins to output to fix this.
> 
> ...
> 
>> +       /* Ensure the pin is in output mode */
> 
> ...in output mode and non-active state */

Ack.

>> +       gpiod_direction_output(int3472->clock.ena_gpio, 0);
> 
> ...
> 
>> +       /* Ensure the pin is in output mode */
>> +       gpiod_direction_output(int3472->regulator.gpio, 0);
> 
> So, previously it was AS IS and now it's non-active state. I believe
> this makes no regressions for the other laptops / platforms.

Correct, and no regression intended indeed. I'll add the improved
comment when merging this (unless there are other / bigger
reasons for a v2).

Regards,

Hans
diff mbox series

Patch

diff --git a/drivers/platform/x86/intel/int3472/clk_and_regulator.c b/drivers/platform/x86/intel/int3472/clk_and_regulator.c
index 89894ec873f2..dc4ab7821b56 100644
--- a/drivers/platform/x86/intel/int3472/clk_and_regulator.c
+++ b/drivers/platform/x86/intel/int3472/clk_and_regulator.c
@@ -103,6 +103,9 @@  int skl_int3472_register_clock(struct int3472_discrete_device *int3472,
 		return dev_err_probe(int3472->dev, ret, "getting regulator GPIO\n");
 	}
 
+	/* Ensure the pin is in output mode */
+	gpiod_direction_output(int3472->clock.ena_gpio, 0);
+
 	init.name = kasprintf(GFP_KERNEL, "%s-clk",
 			      acpi_dev_name(int3472->adev));
 	if (!init.name) {
@@ -195,6 +198,9 @@  int skl_int3472_register_regulator(struct int3472_discrete_device *int3472,
 		return PTR_ERR(int3472->regulator.gpio);
 	}
 
+	/* Ensure the pin is in output mode */
+	gpiod_direction_output(int3472->regulator.gpio, 0);
+
 	cfg.dev = &int3472->adev->dev;
 	cfg.init_data = &init_data;
 	cfg.ena_gpiod = int3472->regulator.gpio;