diff options
| -rw-r--r-- | drivers/i2c/i2c-core-of-prober.c | 138 | ||||
| -rw-r--r-- | include/linux/i2c-of-prober.h | 44 |
2 files changed, 181 insertions, 1 deletions
diff --git a/drivers/i2c/i2c-core-of-prober.c b/drivers/i2c/i2c-core-of-prober.c index 21f7a4769293..76df75c51cae 100644 --- a/drivers/i2c/i2c-core-of-prober.c +++ b/drivers/i2c/i2c-core-of-prober.c @@ -6,6 +6,7 @@ */ #include <linux/cleanup.h> +#include <linux/delay.h> #include <linux/device.h> #include <linux/dev_printk.h> #include <linux/err.h> @@ -13,6 +14,7 @@ #include <linux/i2c-of-prober.h> #include <linux/module.h> #include <linux/of.h> +#include <linux/regulator/consumer.h> #include <linux/slab.h> #include <linux/stddef.h> @@ -29,7 +31,6 @@ * address responds. * * TODO: - * - Support handling common regulators. * - Support handling common GPIOs. * - Support I2C muxes */ @@ -181,3 +182,138 @@ out_put_i2c_adapter: return ret; } EXPORT_SYMBOL_NS_GPL(i2c_of_probe_component, I2C_OF_PROBER); + +static int i2c_of_probe_simple_get_supply(struct device *dev, struct device_node *node, + struct i2c_of_probe_simple_ctx *ctx) +{ + const char *supply_name; + struct regulator *supply; + + /* + * It's entirely possible for the component's device node to not have the + * regulator supplies. While it does not make sense from a hardware perspective, + * the supplies could be always on or otherwise not modeled in the device tree, + * but the device would still work. + */ + supply_name = ctx->opts->supply_name; + if (!supply_name) + return 0; + + supply = of_regulator_get_optional(dev, node, supply_name); + if (IS_ERR(supply)) { + return dev_err_probe(dev, PTR_ERR(supply), + "Failed to get regulator supply \"%s\" from %pOF\n", + supply_name, node); + } + + ctx->supply = supply; + + return 0; +} + +static void i2c_of_probe_simple_put_supply(struct i2c_of_probe_simple_ctx *ctx) +{ + regulator_put(ctx->supply); + ctx->supply = NULL; +} + +static int i2c_of_probe_simple_enable_regulator(struct device *dev, struct i2c_of_probe_simple_ctx *ctx) +{ + int ret; + + if (!ctx->supply) + return 0; + + dev_dbg(dev, "Enabling regulator supply \"%s\"\n", ctx->opts->supply_name); + + ret = regulator_enable(ctx->supply); + if (ret) + return ret; + + if (ctx->opts->post_power_on_delay_ms) + msleep(ctx->opts->post_power_on_delay_ms); + + return 0; +} + +static void i2c_of_probe_simple_disable_regulator(struct device *dev, struct i2c_of_probe_simple_ctx *ctx) +{ + if (!ctx->supply) + return; + + dev_dbg(dev, "Disabling regulator supply \"%s\"\n", ctx->opts->supply_name); + + regulator_disable(ctx->supply); +} + +/** + * i2c_of_probe_simple_enable - Simple helper for I2C OF prober to get and enable resources + * @dev: Pointer to the &struct device of the caller, only used for dev_printk() messages + * @bus_node: Pointer to the &struct device_node of the I2C adapter. + * @data: Pointer to &struct i2c_of_probe_simple_ctx helper context. + * + * If &i2c_of_probe_simple_opts->supply_name is given, request the named regulator supply. + * If a regulator supply was found, enable that regulator. + * + * Return: %0 on success or no-op, or a negative error number on failure. + */ +int i2c_of_probe_simple_enable(struct device *dev, struct device_node *bus_node, void *data) +{ + struct i2c_of_probe_simple_ctx *ctx = data; + struct device_node *node; + const char *compat; + int ret; + + dev_dbg(dev, "Requesting resources for components under I2C bus %pOF\n", bus_node); + + if (!ctx || !ctx->opts) + return -EINVAL; + + compat = ctx->opts->res_node_compatible; + if (!compat) + return -EINVAL; + + node = of_get_compatible_child(bus_node, compat); + if (!node) + return dev_err_probe(dev, -ENODEV, "No device compatible with \"%s\" found\n", + compat); + + ret = i2c_of_probe_simple_get_supply(dev, node, ctx); + if (ret) + goto out_put_node; + + ret = i2c_of_probe_simple_enable_regulator(dev, ctx); + if (ret) + goto out_put_supply; + + return 0; + +out_put_supply: + i2c_of_probe_simple_put_supply(ctx); +out_put_node: + of_node_put(node); + return ret; +} +EXPORT_SYMBOL_NS_GPL(i2c_of_probe_simple_enable, I2C_OF_PROBER); + +/** + * i2c_of_probe_simple_cleanup - Clean up and release resources for I2C OF prober simple helpers + * @dev: Pointer to the &struct device of the caller, only used for dev_printk() messages + * @data: Pointer to &struct i2c_of_probe_simple_ctx helper context. + * + * * If a regulator supply was found, disable that regulator and release it. + */ +void i2c_of_probe_simple_cleanup(struct device *dev, void *data) +{ + struct i2c_of_probe_simple_ctx *ctx = data; + + i2c_of_probe_simple_disable_regulator(dev, ctx); + i2c_of_probe_simple_put_supply(ctx); +} +EXPORT_SYMBOL_NS_GPL(i2c_of_probe_simple_cleanup, I2C_OF_PROBER); + +struct i2c_of_probe_ops i2c_of_probe_simple_ops = { + .enable = i2c_of_probe_simple_enable, + .cleanup = i2c_of_probe_simple_cleanup, +}; +EXPORT_SYMBOL_NS_GPL(i2c_of_probe_simple_ops, I2C_OF_PROBER); diff --git a/include/linux/i2c-of-prober.h b/include/linux/i2c-of-prober.h index e7e052ac9e48..df95aa6ad90e 100644 --- a/include/linux/i2c-of-prober.h +++ b/include/linux/i2c-of-prober.h @@ -70,6 +70,50 @@ struct i2c_of_probe_cfg { int i2c_of_probe_component(struct device *dev, const struct i2c_of_probe_cfg *cfg, void *ctx); +/** + * DOC: I2C OF component prober simple helpers + * + * Components such as trackpads are commonly connected to a devices baseboard + * with a 6-pin ribbon cable. That gives at most one voltage supply and one + * GPIO (commonly a "enable" or "reset" line) besides the I2C bus, interrupt + * pin, and common ground. Touchscreens, while integrated into the display + * panel's connection, typically have the same set of connections. + * + * A simple set of helpers are provided here for use with the I2C OF component + * prober. This implementation targets such components, allowing for at most + * one regulator supply. + * + * The following helpers are provided: + * * i2c_of_probe_simple_enable() + * * i2c_of_probe_simple_cleanup() + */ + +/** + * struct i2c_of_probe_simple_opts - Options for simple I2C component prober callbacks + * @res_node_compatible: Compatible string of device node to retrieve resources from. + * @supply_name: Name of regulator supply. + * @post_power_on_delay_ms: Delay after regulators are powered on. Passed to msleep(). + */ +struct i2c_of_probe_simple_opts { + const char *res_node_compatible; + const char *supply_name; + unsigned int post_power_on_delay_ms; +}; + +struct regulator; + +struct i2c_of_probe_simple_ctx { + /* public: provided by user before helpers are used. */ + const struct i2c_of_probe_simple_opts *opts; + /* private: internal fields for helpers. */ + struct regulator *supply; +}; + +int i2c_of_probe_simple_enable(struct device *dev, struct device_node *bus_node, void *data); +void i2c_of_probe_simple_cleanup(struct device *dev, void *data); + +extern struct i2c_of_probe_ops i2c_of_probe_simple_ops; + #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */ #endif /* _LINUX_I2C_OF_PROBER_H */ |