From cefae80249f6bf3fdbc7c3a00bc43deb4c1bccf0 Mon Sep 17 00:00:00 2001 From: Luis Oliveira Date: Thu, 26 Jan 2017 17:45:32 +0000 Subject: [PATCH] i2c: core: helper function to detect slave mode This function has the purpose of mode detection by checking the device nodes for a reg matching with the I2C_OWN_SLAVE_ADDREESS flag. Currently only checks using OF functions (ACPI slave not supported yet). Signed-off-by: Luis Oliveira Suggested-by: Andy Shevchenko Reviewed-by: Andy Shevchenko Signed-off-by: Wolfram Sang --- drivers/i2c/i2c-core.c | 33 +++++++++++++++++++++++++++++++++ include/linux/i2c.h | 1 + 2 files changed, 34 insertions(+) diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index 583e950..408de74 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -3690,6 +3690,39 @@ int i2c_slave_unregister(struct i2c_client *client) return ret; } EXPORT_SYMBOL_GPL(i2c_slave_unregister); + +/** + * i2c_detect_slave_mode - detect operation mode + * @dev: The device owning the bus + * + * This checks the device nodes for an I2C slave by checking the address + * used in the reg property. If the address match the I2C_OWN_SLAVE_ADDRESS + * flag this means the device is configured to act as a I2C slave and it will + * be listening at that address. + * + * Returns true if an I2C own slave address is detected, otherwise returns + * false. + */ +bool i2c_detect_slave_mode(struct device *dev) +{ + if (IS_BUILTIN(CONFIG_OF) && dev->of_node) { + struct device_node *child; + u32 reg; + + for_each_child_of_node(dev->of_node, child) { + of_property_read_u32(child, "reg", ®); + if (reg & I2C_OWN_SLAVE_ADDRESS) { + of_node_put(child); + return true; + } + } + } else if (IS_BUILTIN(CONFIG_ACPI) && ACPI_HANDLE(dev)) { + dev_dbg(dev, "ACPI slave is not supported yet\n"); + } + return false; +} +EXPORT_SYMBOL_GPL(i2c_detect_slave_mode); + #endif MODULE_AUTHOR("Simon G. Vogl "); diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 4b45ec4..f0ba4ba 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -282,6 +282,7 @@ enum i2c_slave_event { extern int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb); extern int i2c_slave_unregister(struct i2c_client *client); +extern bool i2c_detect_slave_mode(struct device *dev); static inline int i2c_slave_event(struct i2c_client *client, enum i2c_slave_event event, u8 *val) -- 2.7.4