From 9d50f95bc0d5df56f2591b950a251d90bffad094 Mon Sep 17 00:00:00 2001 From: Charles Keepax Date: Tue, 16 Apr 2024 11:09:01 +0100 Subject: gpio: swnode: Add ability to specify native chip selects for SPI SPI devices can specify a cs-gpios property to enumerate their chip selects. Under device tree, a zero entry in this property can be used to specify that a particular chip select is using the SPI controllers native chip select, for example: cs-gpios = <&gpio1 0 0>, <0>; Here, the second chip select is native. However, when using swnodes there is currently no way to specify a native chip select. The proposal here is to register a swnode_gpio_undefined software node, that can be specified to allow the indication of a native chip select. For example: static const struct software_node_ref_args device_cs_refs[] = { { .node = &device_gpiochip_swnode, .nargs = 2, .args = { 0, GPIO_ACTIVE_LOW }, }, { .node = &swnode_gpio_undefined, .nargs = 0, }, }; Register the swnode as the gpiolib is initialised and check in swnode_get_gpio_device() if the returned node matches swnode_gpio_undefined and return -ENOENT, which matches the behaviour of the device tree system when it encounters a 0 phandle. Reviewed-by: Linus Walleij Reviewed-by: Andy Shevchenko Signed-off-by: Charles Keepax Link: https://lore.kernel.org/r/20240416100904.3738093-2-ckeepax@opensource.cirrus.com Signed-off-by: Mark Brown --- include/linux/gpio/property.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux/gpio') diff --git a/include/linux/gpio/property.h b/include/linux/gpio/property.h index 6c75c8bd44a0..832a60c2e0b9 100644 --- a/include/linux/gpio/property.h +++ b/include/linux/gpio/property.h @@ -5,7 +5,11 @@ #include /* for GPIO_* flags */ #include +struct software_node; + #define PROPERTY_ENTRY_GPIO(_name_, _chip_node_, _idx_, _flags_) \ PROPERTY_ENTRY_REF(_name_, _chip_node_, _idx_, _flags_) +extern const struct software_node swnode_gpio_undefined; + #endif /* __LINUX_GPIO_PROPERTY_H */ -- cgit v1.2.3 From 2b5ae9c7d9e5ef4bc52c932fdf10328feb5167c6 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Sun, 5 May 2024 17:14:20 +0300 Subject: gpiolib: Discourage to use formatting strings in line names Currently the documentation for line names allows to use %u inside the alternative name. This is broken in character device approach from day 1 and being in use solely in sysfs. Character device interface has a line number as a part of its address, so the users better rely on it. Hence remove the misleading documentation. On top of that, there are no in-kernel users (out of 6, if I'm correct) for such names and moreover if one exists it won't help in distinguishing lines with the same naming as '%u' will also be in them and we will get a warning in gpiochip_set_desc_names() for such cases. Signed-off-by: Andy Shevchenko Reviewed-by: Linus Walleij Reviewed-by: Kent Gibson Link: https://lore.kernel.org/r/20240505141420.627398-1-andy.shevchenko@gmail.com Signed-off-by: Bartosz Golaszewski --- include/linux/gpio/driver.h | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'include/linux/gpio') diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h index f8617eaf08ba..0032bb6e7d8f 100644 --- a/include/linux/gpio/driver.h +++ b/include/linux/gpio/driver.h @@ -376,9 +376,7 @@ struct gpio_irq_chip { * @names: if set, must be an array of strings to use as alternative * names for the GPIOs in this chip. Any entry in the array * may be NULL if there is no alias for the GPIO, however the - * array must be @ngpio entries long. A name can include a single printk - * format specifier for an unsigned int. It is substituted by the actual - * number of the gpio. + * array must be @ngpio entries long. * @can_sleep: flag must be set iff get()/set() methods sleep, as they * must while accessing GPIO expander chips over I2C or SPI. This * implies that if the chip supports IRQs, these IRQs need to be threaded -- cgit v1.2.3