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[v5,0/2] Fix Nvidia BlueField-3 GPIO access

Message ID 20230818164314.8505-1-asmaa@nvidia.com
Headers show
Series Fix Nvidia BlueField-3 GPIO access | expand

Message

Asmaa Mnebhi Aug. 18, 2023, 4:43 p.m. UTC 
Fix Nvidia BlueField-3 GPIO access via libgpiod gpioset tool.
gpioset tool fails to modify the GPIO value due to the following:
1) the pinctrl-mlxbf3 driver defines mlxbf3_gpio_request_enable()
   to enable software to take control over a gpio. Only then can
   the gpio-mlxbf3 driver modify the direction and value of the
   gpio. mlxbf3_gpio_disable_free() gives control back to hardware
   and is called when the "gpioset" command is invoked.
   This cancels out the effort to change the GPIO value and
   direction. So mlxbf3_gpio_disable_free() needs to be removed.
2) the gpio-mlxbf3 driver calls gpiochip_generic_request() which
   calls mlxbf3_gpio_request_enable(). "pin_ranges" needs not to be
   empty for mlxbf3_gpio_request_enable() to be invoked. So
   gpio-mlxbf3 needs to populate "pin_ranges".


Asmaa Mnebhi (2):
  pinctrl: mlxbf3: Remove gpio_disable_free()
  gpio: mlxbf3: Support add_pin_ranges()

 drivers/gpio/gpio-mlxbf3.c       | 24 ++++++++++++++++++++++++
 drivers/pinctrl/pinctrl-mlxbf3.c | 14 --------------
 2 files changed, 24 insertions(+), 14 deletions(-)

Comments

Linus Walleij Aug. 21, 2023, 7:31 a.m. UTC | #1 
On Fri, Aug 18, 2023 at 6:43 PM Asmaa Mnebhi <asmaa@nvidia.com> wrote:

> Fix Nvidia BlueField-3 GPIO access via libgpiod gpioset tool.
> gpioset tool fails to modify the GPIO value due to the following:
> 1) the pinctrl-mlxbf3 driver defines mlxbf3_gpio_request_enable()
>    to enable software to take control over a gpio. Only then can
>    the gpio-mlxbf3 driver modify the direction and value of the
>    gpio. mlxbf3_gpio_disable_free() gives control back to hardware
>    and is called when the "gpioset" command is invoked.
>    This cancels out the effort to change the GPIO value and
>    direction. So mlxbf3_gpio_disable_free() needs to be removed.
> 2) the gpio-mlxbf3 driver calls gpiochip_generic_request() which
>    calls mlxbf3_gpio_request_enable(). "pin_ranges" needs not to be
>    empty for mlxbf3_gpio_request_enable() to be invoked. So
>    gpio-mlxbf3 needs to populate "pin_ranges".

This patch set looks good to me!
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij