From: Marco Felsch <[email protected]> The of_xlate function can be used to by drivers which need a other gpio encoding than:
gpio = <&phandle gpio-nr gpio-flags>; The of_xlate code is as close as possible to the kernel counter part which makes it easier to add 'struct gpio_desc' support later on. Signed-off-by: Marco Felsch <[email protected]> Reviewed-by: Ahmad Fatoum <[email protected]> Signed-off-by: Ahmad Fatoum <[email protected]> --- v1 -> v2: - fix typos (Jules) - forward-declare struct of_phandle_args in header - use WARN_ON in if condition instead of WARN_ON(1) in body - use early exits in of_find_gpiochip_by_xlate --- drivers/gpio/gpiolib.c | 49 ++++++++++++++++++++++++++++++++++++ drivers/of/of_gpio.c | 56 +++++++++++++++++++++++++++++++++--------- include/gpio.h | 26 ++++++++++++++++++++ 3 files changed, 119 insertions(+), 12 deletions(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 5e753d1c7300..f353ce50196c 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -590,6 +590,41 @@ static int of_gpiochip_set_names(struct gpio_chip *chip) return 0; } +/** + * of_gpio_simple_xlate - translate gpiospec to the GPIO number and flags + * @gc: pointer to the gpio_chip structure + * @gpiospec: GPIO specifier as found in the device tree + * @flags: a flags pointer to fill in + * + * This is simple translation function, suitable for the most 1:1 mapped + * GPIO chips. This function performs only one sanity check: whether GPIO + * is less than ngpios (that is specified in the gpio_chip). + */ +static int of_gpio_simple_xlate(struct gpio_chip *gc, + const struct of_phandle_args *gpiospec, + u32 *flags) +{ + /* + * We're discouraging gpio_cells < 2, since that way you'll have to + * write your own xlate function (that will have to retrieve the GPIO + * number and the flags from a single gpio cell -- this is possible, + * but not recommended). + */ + if (WARN_ON(gc->of_gpio_n_cells < 2)) + return -EINVAL; + + if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells)) + return -EINVAL; + + if (gpiospec->args[0] >= gc->ngpio) + return -EINVAL; + + if (flags) + *flags = gpiospec->args[1]; + + return gc->base + gpiospec->args[0]; +} + static int of_gpiochip_add(struct gpio_chip *chip) { struct device_node *np; @@ -599,6 +634,20 @@ static int of_gpiochip_add(struct gpio_chip *chip) if (!np) return 0; + if (!chip->ops->of_xlate) + chip->ops->of_xlate = of_gpio_simple_xlate; + + /* + * Separate check since the 'struct gpio_ops' is always the same for + * every 'struct gpio_chip' of the same instance (e.g. 'struct + * imx_gpio_chip'). + */ + if (chip->ops->of_xlate == of_gpio_simple_xlate) + chip->of_gpio_n_cells = 2; + + if (chip->of_gpio_n_cells > MAX_PHANDLE_ARGS) + return -EINVAL; + ret = of_gpiochip_set_names(chip); if (ret) return ret; diff --git a/drivers/of/of_gpio.c b/drivers/of/of_gpio.c index 76398f75422f..7a6435e2296a 100644 --- a/drivers/of/of_gpio.c +++ b/drivers/of/of_gpio.c @@ -46,6 +46,44 @@ static void of_gpio_flags_quirks(struct device_node *np, } +static struct gpio_chip *of_find_gpiochip_by_xlate( + struct of_phandle_args *gpiospec) +{ + struct gpio_chip *chip; + struct device *dev; + + dev = of_find_device_by_node(gpiospec->np); + if (!dev) { + pr_debug("%s: unable to find device of node %pOF\n", + __func__, gpiospec->np); + return NULL; + } + + chip = gpio_get_chip_by_dev(dev); + if (!chip) { + pr_debug("%s: unable to find gpiochip\n", __func__); + return NULL; + } + + if (!chip->ops->of_xlate || + chip->ops->of_xlate(chip, gpiospec, NULL) < 0) { + pr_err("%s: failed to execute of_xlate\n", __func__); + return NULL; + } + + return chip; +} + +static int of_xlate_and_get_gpiod_flags(struct gpio_chip *chip, + struct of_phandle_args *gpiospec, + enum of_gpio_flags *flags) +{ + if (chip->of_gpio_n_cells != gpiospec->args_count) + return -EINVAL; + + return chip->ops->of_xlate(chip, gpiospec, flags); +} + /** * of_get_named_gpio_flags() - Get a GPIO number and flags to use with GPIO API * @np: device node to get GPIO from @@ -61,7 +99,7 @@ int of_get_named_gpio_flags(struct device_node *np, const char *propname, int index, enum of_gpio_flags *flags) { struct of_phandle_args gpiospec; - struct device *dev; + struct gpio_chip *chip; int ret; ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", @@ -72,27 +110,21 @@ int of_get_named_gpio_flags(struct device_node *np, const char *propname, return ret; } - dev = of_find_device_by_node(gpiospec.np); - if (!dev) { - pr_debug("%s: unable to find device of node %s\n", - __func__, gpiospec.np->full_name); + chip = of_find_gpiochip_by_xlate(&gpiospec); + if (!chip) { ret = -EPROBE_DEFER; goto out; } - ret = gpio_get_num(dev, gpiospec.args[0]); - if (ret == -EPROBE_DEFER) - goto out; + ret = of_xlate_and_get_gpiod_flags(chip, &gpiospec, flags); if (ret < 0) { pr_err("%s: unable to get gpio num of device %s: %d\n", - __func__, dev_name(dev), ret); + __func__, dev_name(chip->dev), ret); goto out; } - if (flags) { - *flags = gpiospec.args[1]; + if (flags) of_gpio_flags_quirks(np, propname, flags, index); - } out: of_node_put(gpiospec.np); diff --git a/include/gpio.h b/include/gpio.h index 5f2c16584c3b..9951532084ac 100644 --- a/include/gpio.h +++ b/include/gpio.h @@ -168,6 +168,7 @@ int gpio_array_to_id(const struct gpio *array, size_t num, u32 *val); #endif struct gpio_chip; +struct of_phandle_args; struct gpio_ops { int (*request)(struct gpio_chip *chip, unsigned offset); @@ -177,6 +178,22 @@ struct gpio_ops { int (*get_direction)(struct gpio_chip *chip, unsigned offset); int (*get)(struct gpio_chip *chip, unsigned offset); void (*set)(struct gpio_chip *chip, unsigned offset, int value); + +#if defined(CONFIG_OF_GPIO) + /* + * If CONFIG_OF_GPIO is enabled, then all GPIO controllers described in + * the device tree automatically may have an OF translation + */ + + /** + * @of_xlate: + * + * Callback to translate a device tree GPIO specifier into a chip- + * relative GPIO number and flags. + */ + int (*of_xlate)(struct gpio_chip *gc, + const struct of_phandle_args *gpiospec, u32 *flags); +#endif }; struct gpio_chip { @@ -185,6 +202,15 @@ struct gpio_chip { int base; int ngpio; +#if defined(CONFIG_OF_GPIO) + /** + * @of_gpio_n_cells: + * + * Number of cells used to form the GPIO specifier. + */ + unsigned int of_gpio_n_cells; +#endif + struct gpio_ops *ops; struct list_head list; -- 2.39.2
