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Commit cefae802 authored by Luis Oliveira's avatar Luis Oliveira Committed by Wolfram Sang
Browse files

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: default avatarLuis Oliveira <lolivei@synopsys.com>
Suggested-by: default avatarAndy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: default avatarAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 50b918c5

drivers/i2c/i2c-core.c

+33 −0
Original line number Diff line number Diff line
@@ -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", &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 <simon@tk.uni-linz.ac.at>");

include/linux/i2c.h

+1 −0
Original line number Diff line number Diff line
@@ -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)