[PATCH v4 3/3] gpiolib: Show correct direction from the beginning

[PATCH v4 3/3] gpiolib: Show correct direction from the beginning

[Ricardo Ribalda Delgado]

Current code assumes that the direction is input if direction_input
function is set.
This might not be the case on GPIOs with programmable direction.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
---
Changelog v4:

timur@kernel.org:
Remove REVISIT comment

 drivers/gpio/gpiolib.c | 27 +++++++++++++--------------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 6925196136ce..cad859fece65 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1344,20 +1344,6 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
 
 	spin_unlock_irqrestore(&gpio_lock, flags);
 
-	for (i = 0; i < chip->ngpio; i++) {
-		struct gpio_desc *desc = &gdev->descs[i];
-
-		desc->gdev = gdev;
-
-		/* REVISIT: most hardware initializes GPIOs as inputs (often
-		 * with pullups enabled) so power usage is minimized. Linux
-		 * code should set the gpio direction first thing; but until
-		 * it does, and in case chip->get_direction is not set, we may
-		 * expose the wrong direction in sysfs.
-		 */
-		desc->flags = !chip->direction_input ? (1 << FLAG_IS_OUT) : 0;
-	}
-
 #ifdef CONFIG_PINCTRL
 	INIT_LIST_HEAD(&gdev->pin_ranges);
 #endif
@@ -1374,6 +1360,19 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
 	if (status)
 		goto err_remove_irqchip_mask;
 
+	for (i = 0; i < chip->ngpio; i++) {
+		struct gpio_desc *desc = &gdev->descs[i];
+
+		desc->gdev = gdev;
+
+		if (chip->get_direction && gpiochip_line_is_valid(chip, i))
+			desc->flags = !chip->get_direction(chip, i) ?
+					(1 << FLAG_IS_OUT) : 0;
+		else
+			desc->flags = !chip->direction_input ?
+					(1 << FLAG_IS_OUT) : 0;
+	}
+
 	status = gpiochip_add_irqchip(chip, lock_key, request_key);
 	if (status)
 		goto err_remove_chip;
-- 
2.19.0

Re: [PATCH v4 3/3] gpiolib: Show correct direction from the beginning

[Jeffrey Hugo]

On 10/2/2018 8:08 AM, Ricardo Ribalda Delgado wrote:
> Current code assumes that the direction is input if direction_input
> function is set.
> This might not be the case on GPIOs with programmable direction.
> 
> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>

I'll try to get this series tested on QDF2400 by the end of the week.

> ---
> Changelog v4:
> 
> timur@kernel.org:
> Remove REVISIT comment
> 
>   drivers/gpio/gpiolib.c | 27 +++++++++++++--------------
>   1 file changed, 13 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index 6925196136ce..cad859fece65 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -1344,20 +1344,6 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
>   
>   	spin_unlock_irqrestore(&gpio_lock, flags);
>   
> -	for (i = 0; i < chip->ngpio; i++) {
> -		struct gpio_desc *desc = &gdev->descs[i];
> -
> -		desc->gdev = gdev;
> -
> -		/* REVISIT: most hardware initializes GPIOs as inputs (often
> -		 * with pullups enabled) so power usage is minimized. Linux
> -		 * code should set the gpio direction first thing; but until
> -		 * it does, and in case chip->get_direction is not set, we may
> -		 * expose the wrong direction in sysfs.
> -		 */
> -		desc->flags = !chip->direction_input ? (1 << FLAG_IS_OUT) : 0;
> -	}
> -
>   #ifdef CONFIG_PINCTRL
>   	INIT_LIST_HEAD(&gdev->pin_ranges);
>   #endif
> @@ -1374,6 +1360,19 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
>   	if (status)
>   		goto err_remove_irqchip_mask;
>   
> +	for (i = 0; i < chip->ngpio; i++) {
> +		struct gpio_desc *desc = &gdev->descs[i];
> +
> +		desc->gdev = gdev;
> +
> +		if (chip->get_direction && gpiochip_line_is_valid(chip, i))
> +			desc->flags = !chip->get_direction(chip, i) ?
> +					(1 << FLAG_IS_OUT) : 0;
> +		else
> +			desc->flags = !chip->direction_input ?
> +					(1 << FLAG_IS_OUT) : 0;
> +	}
> +
>   	status = gpiochip_add_irqchip(chip, lock_key, request_key);
>   	if (status)
>   		goto err_remove_chip;
> 


-- 
Jeffrey Hugo
Qualcomm Datacenter Technologies as an affiliate of Qualcomm 
Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.

Re: [PATCH v4 3/3] gpiolib: Show correct direction from the beginning

[Jeffrey Hugo]

On 10/2/2018 9:21 AM, Jeffrey Hugo wrote:
> On 10/2/2018 8:08 AM, Ricardo Ribalda Delgado wrote:
>> Current code assumes that the direction is input if direction_input
>> function is set.
>> This might not be the case on GPIOs with programmable direction.
>>
>> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
> 
> I'll try to get this series tested on QDF2400 by the end of the week. 

1-2/3 (v3) and 3/3 (v4) still fails.  Same issue.  Attempting to access 
config registers for GPIO 0 when the OS is not allowed to do that.

-- 
Jeffrey Hugo
Qualcomm Datacenter Technologies as an affiliate of Qualcomm 
Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.

Re: [PATCH v4 3/3] gpiolib: Show correct direction from the beginning

[Ricardo Ribalda Delgado]

Hi
On Fri, Oct 5, 2018 at 12:26 AM Jeffrey Hugo <jhugo@codeaurora.org> wrote:
>
> On 10/2/2018 9:21 AM, Jeffrey Hugo wrote:
> > On 10/2/2018 8:08 AM, Ricardo Ribalda Delgado wrote:
> >> Current code assumes that the direction is input if direction_input
> >> function is set.
> >> This might not be the case on GPIOs with programmable direction.
> >>
> >> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
> >
> > I'll try to get this series tested on QDF2400 by the end of the week.
>
> 1-2/3 (v3) and 3/3 (v4) still fails.  Same issue.  Attempting to access
> config registers for GPIO 0 when the OS is not allowed to do that.
>

I think that I might found the bug. if gpio-reserved-ranges was
present the initialization was lost.

Can you try with v5

Thanks for your help

> --
> Jeffrey Hugo
> Qualcomm Datacenter Technologies as an affiliate of Qualcomm
> Technologies, Inc.
> Qualcomm Technologies, Inc. is a member of the
> Code Aurora Forum, a Linux Foundation Collaborative Project.



-- 
Ricardo Ribalda

Re: [PATCH v4 3/3] gpiolib: Show correct direction from the beginning

[Jeffrey Hugo]

On 10/5/2018 12:52 AM, Ricardo Ribalda Delgado wrote:
> Hi
> On Fri, Oct 5, 2018 at 12:26 AM Jeffrey Hugo <jhugo@codeaurora.org> wrote:
>>
>> On 10/2/2018 9:21 AM, Jeffrey Hugo wrote:
>>> On 10/2/2018 8:08 AM, Ricardo Ribalda Delgado wrote:
>>>> Current code assumes that the direction is input if direction_input
>>>> function is set.
>>>> This might not be the case on GPIOs with programmable direction.
>>>>
>>>> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
>>>
>>> I'll try to get this series tested on QDF2400 by the end of the week.
>>
>> 1-2/3 (v3) and 3/3 (v4) still fails.  Same issue.  Attempting to access
>> config registers for GPIO 0 when the OS is not allowed to do that.
>>
> 
> I think that I might found the bug. if gpio-reserved-ranges was
> present the initialization was lost.
> 
> Can you try with v5
> 
> Thanks for your help

I'll let you know how it goes.

-- 
Jeffrey Hugo
Qualcomm Datacenter Technologies as an affiliate of Qualcomm 
Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.