Add support for the upstream gpio-line-names property already described in the common GPIO binding document[1]. The ability to search for a line name allows boards to lift the implementation of common GPIO behaviours away from specific line indexes on a GPIO controller.

[1] https://github.com/devicetree-org/dt-schema/blob/3c35bfee83c2e38e2ae7af5f83e...

Signed-off-by: Andrew Jeffery andrew@aj.id.au --- Hi,

This patch is extracted from and motivated by a series adding run-time control of FIT signature verification to u-boot in OpenBMC:

https://lore.kernel.org/openbmc/20220131012538.73021-1-andrew@aj.id.au/

Unfortunately the OpenBMC u-boot tree is quite a way behind on tracking upstream and contains a bunch of out-of-tree work as well. As such I'm looking to upstream the couple of changes that make sense against master.

Please take a look!

Andrew

drivers/gpio/gpio-uclass.c | 26 ++++++++++++++++++++++++++ include/asm-generic/gpio.h | 19 +++++++++++++++++++ 2 files changed, 45 insertions(+)

diff --git a/drivers/gpio/gpio-uclass.c b/drivers/gpio/gpio-uclass.c index 125ae53d612f..be00a1f7d871 100644 --- a/drivers/gpio/gpio-uclass.c +++ b/drivers/gpio/gpio-uclass.c @@ -1187,6 +1187,32 @@ int gpio_request_by_name(struct udevice *dev, const char *list_name, int index, index, desc, flags, index > 0, NULL); }

+int gpio_request_by_line_name(struct udevice *dev, const char *line_name, + struct gpio_desc *desc, int flags) +{ + int ret; + + ret = dev_read_stringlist_search(dev, "gpio-line-names", line_name); + if (ret < 0) + return ret; + + desc->dev = dev; + desc->offset = ret; + desc->flags = 0; + + ret = dm_gpio_request(desc, line_name); + if (ret) { + debug("%s: dm_gpio_requestf failed\n", __func__); + return ret; + } + + ret = dm_gpio_set_dir_flags(desc, flags | desc->flags); + if (ret) + debug("%s: dm_gpio_set_dir failed\n", __func__); + + return ret; +} + int gpio_request_list_by_name_nodev(ofnode node, const char *list_name, struct gpio_desc *desc, int max_count, int flags) diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h index adc19e9765d7..81f63f06f15e 100644 --- a/include/asm-generic/gpio.h +++ b/include/asm-generic/gpio.h @@ -579,6 +579,25 @@ int gpio_claim_vector(const int *gpio_num_array, const char *fmt); int gpio_request_by_name(struct udevice *dev, const char *list_name, int index, struct gpio_desc *desc, int flags);

+/* gpio_request_by_line_name - Locate and request a GPIO by line name + * + * Request a GPIO using the offset of the provided line name in the + * gpio-line-names property found in the OF node of the GPIO udevice. + * + * This allows boards to implement common behaviours using GPIOs while not + * requiring specific GPIO offsets be used. + * + * @dev: An instance of a GPIO controller udevice + * @line_name: The name of the GPIO (e.g. "bmc-secure-boot") + * @desc: A GPIO descriptor that is populated with the requested GPIO + * upon return + * @flags: The GPIO settings apply to the request + * @return 0 if the named line was found and requested successfully, or a + * negative error code if the GPIO cannot be found or the request failed. + */ +int gpio_request_by_line_name(struct udevice *dev, const char *line_name, + struct gpio_desc *desc, int flags); + /** * gpio_request_list_by_name() - Request a list of GPIOs *