Re: [RFC PATCH v3 2/5] pinctrl: add dt binding support for pinmux mappings

[Marek Vasut <marek.vasut@gmail.com>]

> From: Dong Aisheng <dong.aisheng@linaro.org>
> 
> This patch provies a common API for driver to use to register pinmux
> mappings from dts file. It is needed for dt support.
> 
> Signed-off-by: Dong Aisheng <dong.aisheng@linaro.org>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Cc: Grant Likely <grant.likely@secretlab.ca>
> Cc: Rob Herring <rob.herring@calxeda.com>
> ---
>  .../devicetree/bindings/pinctrl/pinctrl.txt        |   33 +++++++
>  drivers/pinctrl/pinmux.c                           |  101
> ++++++++++++++++++++ include/linux/pinctrl/machine.h                    | 
>   6 +
>  3 files changed, 140 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/pinctrl/pinctrl.txt
> 
> diff --git a/Documentation/devicetree/bindings/pinctrl/pinctrl.txt
> b/Documentation/devicetree/bindings/pinctrl/pinctrl.txt new file mode
> 100644
> index 0000000..a27a7ce
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pinctrl/pinctrl.txt
> @@ -0,0 +1,33 @@
> +The pin control subsystem
> +
> +The pin control subsystem provides a common API to support parsing pinmux
> +mappings data from device tree. Each board dts file should provide a
> device +node of which all the child nodes are the corresponding pinmux
> mappings. +
> +The required properties for pinmux mapping are:
> +- map-name: the name of this specific map entry
> +- clk-dev-name: the name of the device controlling this specific mapping
> +- funcion: a function in the driver to use for this mapping
> +
> +Optional properties:
> +- group: a certain specific pin group to activate for the function
> +- dev-name: the name of the device using this specific mapping
> +- hog-on-boot: indicate wether hog the mappings(do not need to specify
> value) +
> +Examples:
> +
> +pinmux: imx6q-sabreauto-map {
> +	map-sd4 {
> +		map-name = "usdhc4";
> +		ctrl-dev-name = "20e0000.iomuxc";
> +		function = "sd4";
> +		dev-name = "219c000.usdhc";
> +	};
> +	...
> +};
> +
> +Then calling pinmux_of_register_mappings() with the device node of
> +imx6q-sabreauto-map as parameter to register pinmux mappings from dts.
> +
> +Usually user can get this device node via a phandle in driver then call
> +the function to register maps. Please refer to pinctrl-imx.txt for
> example. diff --git a/drivers/pinctrl/pinmux.c b/drivers/pinctrl/pinmux.c
> index 432feb6..3ac3098 100644
> --- a/drivers/pinctrl/pinmux.c
> +++ b/drivers/pinctrl/pinmux.c
> @@ -20,6 +20,7 @@
>  #include <linux/err.h>
>  #include <linux/list.h>
>  #include <linux/mutex.h>
> +#include <linux/of_device.h>
>  #include <linux/spinlock.h>
>  #include <linux/string.h>
>  #include <linux/sysfs.h>
> @@ -410,6 +411,106 @@ int __init pinmux_register_mappings(struct pinmux_map
> const *maps, return 0;
>  }
> 
> +static int __devinit pinmux_of_parse_mapping(struct device_node *np,
> +					struct pinmux_map *maps, unsigned id)
> +{
> +	struct pinmux_map *map = &maps[id];
> +	int ret = 0;
> +
> +	pr_debug("parse pinmux map %d\n", id + 1);
> +
> +	if (of_find_property(np, "map-name", NULL)) {
> +		ret = of_property_read_string(np, "map-name", &map->name);
> +		if (ret) {
> +			pr_err("failed to get map-name");
> +			return ret;
> +		}
> +	}
> +
> +	if (of_find_property(np, "ctrl-dev-name", NULL)) {
> +		ret = of_property_read_string(np, "ctrl-dev-name",
> +						&map->ctrl_dev_name);
> +		if (ret) {
> +			pr_err("failed to get ctrl-dev-name");
> +			return ret;
> +		}
> +	}
> +
> +	if (of_find_property(np, "function", NULL)) {
> +		ret = of_property_read_string(np, "function", &map->function);
> +		if (ret) {
> +			pr_err("failed to get function");
> +			return ret;
> +		}
> +	}
> +
> +	if (of_find_property(np, "group", NULL)) {
> +		ret = of_property_read_string(np, "group", &map->group);
> +		if (ret) {
> +			pr_err("failed to get group");
> +			return ret;
> +		}
> +	}
> +
> +	if (of_find_property(np, "dev-name", NULL)) {
> +		ret = of_property_read_string(np, "dev-name", &map->dev_name);
> +		if (ret) {
> +			pr_err("failed to get dev-name");
> +			return ret;
> +		}
> +	}
> +
> +	if (of_find_property(np, "hog-on-boot", NULL))
> +		map->hog_on_boot = true;
> +
> +	pr_debug("map-name: %s ctrl-dev-name: %s function: %s group: %s dev-
name:
> %s hog-on-boot: %d\n", +			map->name, map->ctrl_dev_name, 
map->function,
> +			map->group, map->dev_name, map->hog_on_boot);

Line too long maybe?

> +
> +	return 0;
> +}
> +
> +/**
> + * pinmux_of_register_mappings() - parse and register pinmux mappings from
> dt + * &np: a device node containing pinmux map properties
> + *
> + * Like pinmux_register_mappings(), the memory of pinmux maps are owned by
> + * pinctrl core and can not be freed.
> + */
> +int __devinit pinmux_of_register_mappings(struct device_node *np)
> +{
> +	struct pinmux_map *maps;
> +	struct device_node *child = NULL;
> +	int count, i;
> +	int ret;
> +
> +	pr_debug("parse pinmux maps from device node %s\n", np->name);
> +
> +	if (!np)
> +		return -EINVAL;
> +
> +	count = of_get_child_count(np);
> +	if (!count) {
> +		pr_err("no available pinmux maps found\n");
> +		return -EINVAL;
> +	}
> +
> +	maps = kzalloc(count * sizeof(struct pinmux_map), GFP_KERNEL);
> +	if (!maps)
> +		return -ENOMEM;
> +
> +	i = 0;
> +	for_each_child_of_node(np, child) {
> +		ret = pinmux_of_parse_mapping(child, maps, i++);
> +		if (ret) {
> +			pr_err("failed to parse pinmux map\n");
> +			return ret;
> +		}
> +	}
> +
> +	return pinmux_register_mappings(maps, count);
> +}
> +
>  /**
>   * acquire_pins() - acquire all the pins for a certain funcion on a pinmux
>   * @pctldev: the device to take the pins on
> diff --git a/include/linux/pinctrl/machine.h
> b/include/linux/pinctrl/machine.h index ad430e0..74a695d 100644
> --- a/include/linux/pinctrl/machine.h
> +++ b/include/linux/pinctrl/machine.h
> @@ -78,6 +78,7 @@ struct pinmux_map {
>  extern int pinmux_register_mappings(struct pinmux_map const *map,
>  				unsigned num_maps);
> 
> +extern int pinmux_of_register_mappings(struct device_node *np);
>  #else
> 
>  static inline int pinmux_register_mappings(struct pinmux_map const *map,
> @@ -86,5 +87,10 @@ static inline int pinmux_register_mappings(struct
> pinmux_map const *map, return 0;
>  }
> 
> +static inline int pinmux_of_register_mappings(struct device_node *np)
> +{
> +	return 0;
> +}
> +
>  #endif /* !CONFIG_PINMUX */
>  #endif