diff options
Diffstat (limited to 'drivers/i2c/i2c-core-of-prober.c')
| -rw-r--r-- | drivers/i2c/i2c-core-of-prober.c | 100 |
1 files changed, 98 insertions, 2 deletions
diff --git a/drivers/i2c/i2c-core-of-prober.c b/drivers/i2c/i2c-core-of-prober.c index 76df75c51cae..b9ca785f8b17 100644 --- a/drivers/i2c/i2c-core-of-prober.c +++ b/drivers/i2c/i2c-core-of-prober.c @@ -10,6 +10,7 @@ #include <linux/device.h> #include <linux/dev_printk.h> #include <linux/err.h> +#include <linux/gpio/consumer.h> #include <linux/i2c.h> #include <linux/i2c-of-prober.h> #include <linux/module.h> @@ -31,7 +32,6 @@ * address responds. * * TODO: - * - Support handling common GPIOs. * - Support I2C muxes */ @@ -246,6 +246,62 @@ static void i2c_of_probe_simple_disable_regulator(struct device *dev, struct i2c regulator_disable(ctx->supply); } +static int i2c_of_probe_simple_get_gpiod(struct device *dev, struct device_node *node, + struct i2c_of_probe_simple_ctx *ctx) +{ + struct fwnode_handle *fwnode = of_fwnode_handle(node); + struct gpio_desc *gpiod; + const char *con_id; + + /* NULL signals no GPIO needed */ + if (!ctx->opts->gpio_name) + return 0; + + /* An empty string signals an unnamed GPIO */ + if (!ctx->opts->gpio_name[0]) + con_id = NULL; + else + con_id = ctx->opts->gpio_name; + + gpiod = fwnode_gpiod_get_index(fwnode, con_id, 0, GPIOD_ASIS, "i2c-of-prober"); + if (IS_ERR(gpiod)) + return PTR_ERR(gpiod); + + ctx->gpiod = gpiod; + + return 0; +} + +static void i2c_of_probe_simple_put_gpiod(struct i2c_of_probe_simple_ctx *ctx) +{ + gpiod_put(ctx->gpiod); + ctx->gpiod = NULL; +} + +static int i2c_of_probe_simple_set_gpio(struct device *dev, struct i2c_of_probe_simple_ctx *ctx) +{ + int ret; + + if (!ctx->gpiod) + return 0; + + dev_dbg(dev, "Configuring GPIO\n"); + + ret = gpiod_direction_output(ctx->gpiod, ctx->opts->gpio_assert_to_enable); + if (ret) + return ret; + + if (ctx->opts->post_gpio_config_delay_ms) + msleep(ctx->opts->post_gpio_config_delay_ms); + + return 0; +} + +static void i2c_of_probe_simple_disable_gpio(struct device *dev, struct i2c_of_probe_simple_ctx *ctx) +{ + gpiod_set_value(ctx->gpiod, !ctx->opts->gpio_assert_to_enable); +} + /** * 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 @@ -253,7 +309,11 @@ static void i2c_of_probe_simple_disable_regulator(struct device *dev, struct i2c * @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 &i2c_of_probe_simple_opts->gpio_name is given, request the named GPIO. Or if it is + * the empty string, request the unnamed GPIO. * If a regulator supply was found, enable that regulator. + * If a GPIO line was found, configure the GPIO line to output and set value + * according to given options. * * Return: %0 on success or no-op, or a negative error number on failure. */ @@ -282,12 +342,24 @@ int i2c_of_probe_simple_enable(struct device *dev, struct device_node *bus_node, if (ret) goto out_put_node; - ret = i2c_of_probe_simple_enable_regulator(dev, ctx); + ret = i2c_of_probe_simple_get_gpiod(dev, node, ctx); if (ret) goto out_put_supply; + ret = i2c_of_probe_simple_enable_regulator(dev, ctx); + if (ret) + goto out_put_gpiod; + + ret = i2c_of_probe_simple_set_gpio(dev, ctx); + if (ret) + goto out_disable_regulator; + return 0; +out_disable_regulator: + i2c_of_probe_simple_disable_regulator(dev, ctx); +out_put_gpiod: + i2c_of_probe_simple_put_gpiod(ctx); out_put_supply: i2c_of_probe_simple_put_supply(ctx); out_put_node: @@ -297,16 +369,39 @@ out_put_node: EXPORT_SYMBOL_NS_GPL(i2c_of_probe_simple_enable, I2C_OF_PROBER); /** + * i2c_of_probe_simple_cleanup_early - \ + * Simple helper for I2C OF prober to release GPIOs before component is enabled + * @dev: Pointer to the &struct device of the caller; unused. + * @data: Pointer to &struct i2c_of_probe_simple_ctx helper context. + * + * GPIO descriptors are exclusive and have to be released before the + * actual driver probes so that the latter can acquire them. + */ +void i2c_of_probe_simple_cleanup_early(struct device *dev, void *data) +{ + struct i2c_of_probe_simple_ctx *ctx = data; + + i2c_of_probe_simple_put_gpiod(ctx); +} +EXPORT_SYMBOL_NS_GPL(i2c_of_probe_simple_cleanup_early, 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 GPIO line was found and not yet released, set its value to the opposite of that + * set in i2c_of_probe_simple_enable() and release it. * * 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; + /* GPIO operations here are no-ops if i2c_of_probe_simple_cleanup_early was called. */ + i2c_of_probe_simple_disable_gpio(dev, ctx); + i2c_of_probe_simple_put_gpiod(ctx); + i2c_of_probe_simple_disable_regulator(dev, ctx); i2c_of_probe_simple_put_supply(ctx); } @@ -314,6 +409,7 @@ 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_early = i2c_of_probe_simple_cleanup_early, .cleanup = i2c_of_probe_simple_cleanup, }; EXPORT_SYMBOL_NS_GPL(i2c_of_probe_simple_ops, I2C_OF_PROBER); |