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gpio: regmap: add the .fixed_direction_output configuration parameter

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There are GPIO controllers such as the one present in the LX2160ARDB
QIXIS FPGA which have fixed-direction input and output GPIO lines mixed
together in a single register. This cannot be modeled using the
gpio-regmap as-is since there is no way to present the true direction of
a GPIO line.

In order to make this use case possible, add a new configuration
parameter - fixed_direction_output - into the gpio_regmap_config
structure. This will enable user drivers to provide a bitmap that
represents the fixed direction of the GPIO lines.

Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Acked-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Michael Walle <mwalle@kernel.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
This commit is contained in:
Ioana Ciornei 2025-10-14 18:53:53 +03:00 committed by Bartosz Golaszewski
parent d37623132a
commit 00aaae60fa
2 changed files with 29 additions and 2 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

26
drivers/gpio/gpio-regmap.c
View file

@ -31,6 +31,7 @@ struct gpio_regmap {
unsigned int reg_clr_base;
unsigned int reg_dir_in_base;
unsigned int reg_dir_out_base;
unsigned long *fixed_direction_output;
#ifdef CONFIG_REGMAP_IRQ
int regmap_irq_line;
@ -134,6 +135,13 @@ static int gpio_regmap_get_direction(struct gpio_chip *chip,
unsigned int base, val, reg, mask;
int invert, ret;
if (gpio->fixed_direction_output) {
if (test_bit(offset, gpio->fixed_direction_output))
return GPIO_LINE_DIRECTION_OUT;
else
return GPIO_LINE_DIRECTION_IN;
}
if (gpio->reg_dat_base && !gpio->reg_set_base)
return GPIO_LINE_DIRECTION_IN;
if (gpio->reg_set_base && !gpio->reg_dat_base)
@ -284,6 +292,17 @@ struct gpio_regmap *gpio_regmap_register(const struct gpio_regmap_config *config
goto err_free_gpio;
}
if (config->fixed_direction_output) {
gpio->fixed_direction_output = bitmap_alloc(chip->ngpio,
GFP_KERNEL);
if (!gpio->fixed_direction_output) {
ret = -ENOMEM;
goto err_free_gpio;
}
bitmap_copy(gpio->fixed_direction_output,
config->fixed_direction_output, chip->ngpio);
}
/* if not set, assume there is only one register */
gpio->ngpio_per_reg = config->ngpio_per_reg;
if (!gpio->ngpio_per_reg)
@ -300,7 +319,7 @@ struct gpio_regmap *gpio_regmap_register(const struct gpio_regmap_config *config
ret = gpiochip_add_data(chip, gpio);
if (ret < 0)
goto err_free_gpio;
goto err_free_bitmap;
#ifdef CONFIG_REGMAP_IRQ
if (config->regmap_irq_chip) {
@ -309,7 +328,7 @@ struct gpio_regmap *gpio_regmap_register(const struct gpio_regmap_config *config
config->regmap_irq_line, config->regmap_irq_flags,
0, config->regmap_irq_chip, &gpio->irq_chip_data);
if (ret)
goto err_free_gpio;
goto err_free_bitmap;
irq_domain = regmap_irq_get_domain(gpio->irq_chip_data);
} else
@ -326,6 +345,8 @@ struct gpio_regmap *gpio_regmap_register(const struct gpio_regmap_config *config
err_remove_gpiochip:
gpiochip_remove(chip);
err_free_bitmap:
bitmap_free(gpio->fixed_direction_output);
err_free_gpio:
kfree(gpio);
return ERR_PTR(ret);
@ -344,6 +365,7 @@ void gpio_regmap_unregister(struct gpio_regmap *gpio)
#endif
gpiochip_remove(&gpio->gpio_chip);
bitmap_free(gpio->fixed_direction_output);
kfree(gpio);
}
EXPORT_SYMBOL_GPL(gpio_regmap_unregister);

5
include/linux/gpio/regmap.h
View file

@ -38,6 +38,10 @@ struct regmap;
* offset to a register/bitmask pair. If not
* given the default gpio_regmap_simple_xlate()
* is used.
* @fixed_direction_output:
* (Optional) Bitmap representing the fixed direction of
* the GPIO lines. Useful when there are GPIO lines with a
* fixed direction mixed together in the same register.
* @drvdata: (Optional) Pointer to driver specific data which is
* not used by gpio-remap but is provided "as is" to the
* driver callback(s).
@ -85,6 +89,7 @@ struct gpio_regmap_config {
int reg_stride;
int ngpio_per_reg;
struct irq_domain *irq_domain;
unsigned long *fixed_direction_output;
#ifdef CONFIG_REGMAP_IRQ
struct regmap_irq_chip *regmap_irq_chip;