Re: [PATCH v2 2/7] gpio: regmap: Add configurable dir/value order

Michael Walle
2021-05-18T08:39:40Z

Hi,

Am 2021-05-17 21:28, schrieb Sander Vanheule:
> GPIO chips may not support setting the output value when a pin is
> configured as an input, although the current implementation assumes
> this
> is always possible.
>
> Add support for setting pin direction before value. The order defaults
> to setting the value first, but this can be reversed by setting the
> regmap_config.no_set_on_input flag, similar to the corresponding flag
> in
> the gpio-mmio driver.
>
> Signed-off-by: Sander Vanheule <sander@svanheule.net>
> ---
> drivers/gpio/gpio-regmap.c | 20 +++++++++++++++++---
> include/linux/gpio/regmap.h | 3 +++
> 2 files changed, 20 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpio/gpio-regmap.c b/drivers/gpio/gpio-regmap.c
> index 134cedf151a7..1cdb20f8f8b4 100644
> --- a/drivers/gpio/gpio-regmap.c
> +++ b/drivers/gpio/gpio-regmap.c
> @@ -170,14 +170,25 @@ static int gpio_regmap_direction_input(struct
> gpio_chip *chip,
> return gpio_regmap_set_direction(chip, offset, false);
> }
>
> -static int gpio_regmap_direction_output(struct gpio_chip *chip,
> - unsigned int offset, int value)
> +static int gpio_regmap_dir_out_val_first(struct gpio_chip *chip,
> + unsigned int offset, int value)

Can we leave the name as is? TBH I find these two similar names
super confusing. Maybe its just me, though.

> {
> gpio_regmap_set(chip, offset, value);
>
> return gpio_regmap_set_direction(chip, offset, true);
> }
>
> +static int gpio_regmap_dir_out_dir_first(struct gpio_chip *chip,
> + unsigned int offset, int value)
> +{
> + int err;

use ret for consistency here

> +
> + err = gpio_regmap_set_direction(chip, offset, true);
> + gpio_regmap_set(chip, offset, value);
> +
> + return err;
> +}
> +

Instead of adding a new one, we can also just check no_set_on_input
in gpio_regmap_direction_output(), which I'd prefer.

static int gpio_regmap_direction_output(struct gpio_chip *chip,
unsigned int offset, int value)
{
struct gpio_regmap *gpio = gpiochip_get_data(chip);
int ret;

if (gpio->no_set_on_input) {
/* some smart comment here, also mention gliches */
ret = gpio_regmap_set_direction(chip, offset, true);
gpio_regmap_set(chip, offset, value);
} else {
gpio_regmap_set(chip, offset, value);
ret = gpio_regmap_set_direction(chip, offset, true);
}

return ret;
}

> void gpio_regmap_set_drvdata(struct gpio_regmap *gpio, void *data)
> {
> gpio->driver_data = data;
> @@ -277,7 +288,10 @@ struct gpio_regmap *gpio_regmap_register(const
> struct gpio_regmap_config *config
> if (gpio->reg_dir_in_base || gpio->reg_dir_out_base) {
> chip->get_direction = gio_regmap_get_direction;
> chip->direction_input = gpio_regmap_direction_input;
> - chip->direction_output = gpio_regmap_direction_output;
> + if (config->no_set_on_input)
> + chip->direction_output = gpio_regmap_dir_out_dir_first;
> + else
> + chip->direction_output = gpio_regmap_dir_out_val_first;
> }
>
> ret = gpiochip_add_data(chip, gpio);
> diff --git a/include/linux/gpio/regmap.h b/include/linux/gpio/regmap.h
> index 334dd928042b..2a732f8f23be 100644
> --- a/include/linux/gpio/regmap.h
> +++ b/include/linux/gpio/regmap.h
> @@ -30,6 +30,8 @@ struct regmap;
> * @reg_dir_out_base: (Optional) out setting register base address
> * @reg_stride: (Optional) May be set if the registers (of the
> * same type, dat, set, etc) are not consecutive.
> + * @no_set_on_input: Set if output value can only be set when the
> direction
> + * is configured as output.

set_direction_first ?

> * @ngpio_per_reg: Number of GPIOs per register
> * @irq_domain: (Optional) IRQ domain if the controller is
> * interrupt-capable
> @@ -73,6 +75,7 @@ struct gpio_regmap_config {
> unsigned int reg_dir_out_base;
> int reg_stride;
> int ngpio_per_reg;
> + bool no_set_on_input;
> struct irq_domain *irq_domain;
>
> int (*reg_mask_xlate)(struct gpio_regmap *gpio, unsigned int base,

-michael