Re: [PATCH v2 2/5] pinctrl: pinconf-generic: Add API for pinmux propertity in DTS file

[Jerome Brunet <jbrunet@baylibre.com>]

On Thu 26 Dec 2024 at 15:57, Xianwei Zhao via B4 Relay <devnull+xianwei.zhao.amlogic.com@kernel.org> wrote:

> From: Xianwei Zhao <xianwei.zhao@amlogic.com>
>
> When describing pin mux func through pinmux propertity,
> a standard API is added for support. The pinmux contains pin
> identification and mux values, which can include multiple
> pins. And groups configuration use other word. DTS such as:
>
> func-name {
> 	group_alias: group-name{
> 		pinmux= <pin_id << 8 | mux_value)>,
> 			<pin_id << 8 | mux_value)>;

This representation does not seem very generic but more tailored to
your use-case.

> 		bias-pull-up;
> 		drive-strength-microamp = <4000>;

If you want to add pinmux (aka alternate function) selection as a
pinconf prop then I think there should be a single pinmux setting per
group, and as many groups as you need per function defined.

something like

func-foo {
	group-a {
        	groups = "pin_a", "pin_b";
                bias-pull-up;
                alternate-function = <2>;
        };

	group-b {
        	groups = "pin_c"";
                bias-disable;
                alternate-function = <5>;
        };
};

Something similar is already done to handle different pin bias requirement
on single function on amlogic platforms:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/boot/dts/amlogic/meson-axg.dtsi?h=v6.13-rc6#n421


> 	};
> };
>
> Signed-off-by: Xianwei Zhao <xianwei.zhao@amlogic.com>
> ---
>  drivers/pinctrl/pinconf-generic.c       | 130 ++++++++++++++++++++++++++++++++
>  drivers/pinctrl/pinconf.h               |   4 +
>  include/linux/pinctrl/pinconf-generic.h |   4 +
>  3 files changed, 138 insertions(+)
>
> diff --git a/drivers/pinctrl/pinconf-generic.c b/drivers/pinctrl/pinconf-generic.c
> index 0b13d7f17b32..a4d3c12a80c4 100644
> --- a/drivers/pinctrl/pinconf-generic.c
> +++ b/drivers/pinctrl/pinconf-generic.c
> @@ -233,6 +233,67 @@ static void parse_dt_cfg(struct device_node *np,
>  	}
>  }
>  
> +/**
> + * pinconf_generic_parse_dt_pinmux()
> + * parse the pinmux properties into generic pin mux values.
> + * @np: node containing the pinmux properties
> + * @pctldev: pincontrol device
> + * @pid: array with pin identity entries
> + * @pmux: array with pin mux value entries
> + * @npins: number of pins
> + *
> + * pinmux propertity: mux value [0,7]bits and pin identity [8,31]bits.
> + */
> +int pinconf_generic_parse_dt_pinmux(struct device_node *np, struct device *dev,
> +				    unsigned int **pid, unsigned int **pmux,
> +				    unsigned int *npins)
> +{
> +	unsigned int *pid_t;
> +	unsigned int *pmux_t;
> +	struct property *prop;
> +	unsigned int npins_t, i;
> +	u32 value;
> +	int ret;
> +
> +	prop = of_find_property(np, "pinmux", NULL);
> +	if (!prop) {
> +		dev_info(dev, "Missing pinmux property\n");
> +		return -ENOENT;
> +	}
> +
> +	if (!pid || !pmux || !npins) {
> +		dev_err(dev, "paramers error\n");
> +		return -EINVAL;
> +	}
> +
> +	npins_t = prop->length / sizeof(u32);
> +	pid_t = devm_kcalloc(dev, npins_t, sizeof(*pid_t), GFP_KERNEL);
> +	pmux_t = devm_kcalloc(dev, npins_t, sizeof(*pmux_t), GFP_KERNEL);
> +	if (!pid_t || !pmux_t) {
> +		dev_err(dev, "kalloc memory fail\n");
> +		return -ENOMEM;
> +	}
> +	for (i = 0; i < npins_t; i++) {
> +		ret = of_property_read_u32_index(np, "pinmux", i, &value);
> +		if (ret) {
> +			dev_err(dev, "get pinmux value fail\n");
> +			goto exit;
> +		}
> +		pmux_t[i] = value & 0xff;
> +		pid_t[i] = (value >> 8) & 0xffffff;
> +	}
> +	*pid = pid_t;
> +	*pmux = pmux_t;
> +	*npins = npins_t;
> +
> +	return 0;
> +exit:
> +	devm_kfree(dev, pid_t);
> +	devm_kfree(dev, pmux_t);
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(pinconf_generic_parse_dt_pinmux);
> +
>  /**
>   * pinconf_generic_parse_dt_config()
>   * parse the config properties into generic pinconfig values.
> @@ -295,6 +356,75 @@ int pinconf_generic_parse_dt_config(struct device_node *np,
>  }
>  EXPORT_SYMBOL_GPL(pinconf_generic_parse_dt_config);
>  
> +int pinconf_generic_dt_node_to_map_pinmux(struct pinctrl_dev *pctldev,
> +					  struct device_node *np,
> +					  struct pinctrl_map **map,
> +					  unsigned int *num_maps)
> +{
> +	struct device *dev = pctldev->dev;
> +	struct device_node *pnode;
> +	unsigned long *configs = NULL;
> +	unsigned int num_configs = 0;
> +	struct property *prop;
> +	unsigned int reserved_maps;
> +	int reserve;
> +	int ret;
> +
> +	prop = of_find_property(np, "pinmux", NULL);
> +	if (!prop) {
> +		dev_info(dev, "Missing pinmux property\n");
> +		return -ENOENT;
> +	}
> +
> +	pnode = of_get_parent(np);
> +	if (!pnode) {
> +		dev_info(dev, "Missing function node\n");
> +		return -EINVAL;
> +	}
> +
> +	reserved_maps = 0;
> +	*map = NULL;
> +	*num_maps = 0;
> +
> +	ret = pinconf_generic_parse_dt_config(np, pctldev, &configs,
> +					      &num_configs);
> +	if (ret < 0) {
> +		dev_err(dev, "%pOF: could not parse node property\n", np);
> +		return ret;
> +	}
> +
> +	reserve = 1;
> +	if (num_configs)
> +		reserve++;
> +
> +	ret = pinctrl_utils_reserve_map(pctldev, map, &reserved_maps,
> +					num_maps, reserve);
> +	if (ret < 0)
> +		goto exit;
> +
> +	ret = pinctrl_utils_add_map_mux(pctldev, map,
> +					&reserved_maps, num_maps, np->name,
> +					pnode->name);
> +	if (ret < 0)
> +		goto exit;
> +
> +	if (num_configs) {
> +		ret = pinctrl_utils_add_map_configs(pctldev, map, &reserved_maps,
> +						    num_maps, np->name, configs,
> +						    num_configs, PIN_MAP_TYPE_CONFIGS_GROUP);
> +		if (ret < 0)
> +			goto exit;
> +	}
> +
> +exit:
> +	kfree(configs);
> +	if (ret)
> +		pinctrl_utils_free_map(pctldev, *map, *num_maps);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(pinconf_generic_dt_node_to_map_pinmux);
> +
>  int pinconf_generic_dt_subnode_to_map(struct pinctrl_dev *pctldev,
>  		struct device_node *np, struct pinctrl_map **map,
>  		unsigned int *reserved_maps, unsigned int *num_maps,
> diff --git a/drivers/pinctrl/pinconf.h b/drivers/pinctrl/pinconf.h
> index a14c950bc700..a171195b3615 100644
> --- a/drivers/pinctrl/pinconf.h
> +++ b/drivers/pinctrl/pinconf.h
> @@ -138,4 +138,8 @@ int pinconf_generic_parse_dt_config(struct device_node *np,
>  				    struct pinctrl_dev *pctldev,
>  				    unsigned long **configs,
>  				    unsigned int *nconfigs);
> +
> +int pinconf_generic_parse_dt_pinmux(struct device_node *np, struct device *dev,
> +				    unsigned int **pid, unsigned int **pmux,
> +				    unsigned int *npins);
>  #endif
> diff --git a/include/linux/pinctrl/pinconf-generic.h b/include/linux/pinctrl/pinconf-generic.h
> index 53cfde98433d..1bcf071b860e 100644
> --- a/include/linux/pinctrl/pinconf-generic.h
> +++ b/include/linux/pinctrl/pinconf-generic.h
> @@ -232,4 +232,8 @@ static inline int pinconf_generic_dt_node_to_map_all(struct pinctrl_dev *pctldev
>  			PIN_MAP_TYPE_INVALID);
>  }
>  
> +int pinconf_generic_dt_node_to_map_pinmux(struct pinctrl_dev *pctldev,
> +					  struct device_node *np,
> +					  struct pinctrl_map **map,
> +					  unsigned int *num_maps);
>  #endif /* __LINUX_PINCTRL_PINCONF_GENERIC_H */

-- 
Jerome