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authorLuis Oliveira <Luis.Oliveira@synopsys.com>2017-01-26 17:45:32 +0000
committerWolfram Sang <wsa@the-dreams.de>2017-01-28 22:12:37 +0100
commitcefae80249f6bf3fdbc7c3a00bc43deb4c1bccf0 (patch)
tree019fc491fc1a6a0ec825c98d60b8f8268884d40b /drivers/i2c
parent50b918c5a6ffad1d9fae29c4fdcb52383b123665 (diff)
downloadlinux-cefae80249f6bf3fdbc7c3a00bc43deb4c1bccf0.tar.bz2
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 <lolivei@synopsys.com> Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'drivers/i2c')
-rw-r--r--drivers/i2c/i2c-core.c33
1 files changed, 33 insertions, 0 deletions
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 583e95042a21..408de741fec5 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", &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>");