Many Linux drivers use [devm_]gpiod_get to get appropriately configured GPIO descriptors out with little code. Make porting such Linux code easier by providing a semi-compatible gpiod_get function. Main differences:
- It returns a gpio index, so it can be passed to any gpio_ function - It's device-tree only, so it should only be used from drivers that themselves probe from device tree. Signed-off-by: Ahmad Fatoum <[email protected]> --- drivers/gpio/gpiolib.c | 43 ++++++++++++++++++++++++++++++++++++++++++ include/gpiod.h | 26 +++++++++++++++++++++++++ 2 files changed, 69 insertions(+) create mode 100644 include/gpiod.h diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 6088cadd8a18..7b7261d01f24 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -6,6 +6,7 @@ #include <complete.h> #include <gpio.h> #include <of_gpio.h> +#include <gpiod.h> #include <errno.h> #include <malloc.h> @@ -554,6 +555,48 @@ static int of_gpiochip_scan_hogs(struct gpio_chip *chip) return 0; } +/* Linux compatibility helper: Get a GPIO descriptor from device tree */ +int gpiod_get(struct device_d *dev, const char *_con_id, enum gpiod_flags flags) +{ + struct device_node *np = dev->device_node; + enum of_gpio_flags of_flags; + const char *con_id = "gpios", *label = dev_name(dev); + char *buf = NULL; + int gpio; + int ret; + + if (!IS_ENABLED(CONFIG_OFDEVICE) || !dev->device_node) + return -ENODEV; + + if (_con_id) { + con_id = buf = basprintf("%s-gpios", _con_id); + if (!buf) + return -ENOMEM; + } + + gpio = of_get_named_gpio_flags(np, con_id, 0, &of_flags); + free(buf); + + if (!gpio_is_valid(gpio)) + return gpio < 0 ? gpio : -EINVAL; + + if (of_flags & OF_GPIO_ACTIVE_LOW) + flags |= GPIOF_ACTIVE_LOW; + + buf = NULL; + + if (_con_id) { + label = buf = basprintf("%s-%s", dev_name(dev), _con_id); + if (!label) + return -ENOMEM; + } + + ret = gpio_request_one(gpio, flags, label); + free(buf); + + return ret ?: gpio; +} + int gpiochip_add(struct gpio_chip *chip) { int base, i; diff --git a/include/gpiod.h b/include/gpiod.h new file mode 100644 index 000000000000..c8b2cd47a3cb --- /dev/null +++ b/include/gpiod.h @@ -0,0 +1,26 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __GPIOD_H_ +#define __GPIOD_H_ + +#include <gpio.h> +#include <of_gpio.h> + +/** + * Optional flags that can be passed to one of gpiod_* to configure direction + * and output value. These values cannot be OR'd. + */ +enum gpiod_flags { + GPIOD_ASIS = 0, + GPIOD_IN = GPIOF_IN, + /* + * To change this later to a different logic level (i.e. taking + * active low into account), use gpio_direction_active() + */ + GPIOD_OUT_LOW = GPIOF_OUT_INIT_INACTIVE, + GPIOD_OUT_HIGH = GPIOF_OUT_INIT_ACTIVE, +}; + +/* returned gpio descriptor can be passed to any normal gpio_* function */ +int gpiod_get(struct device_d *dev, const char *_con_id, enum gpiod_flags flags); + +#endif -- 2.30.0 _______________________________________________ barebox mailing list [email protected] http://lists.infradead.org/mailman/listinfo/barebox
