[PATCH v3] i2c: core: helper function to detect slave mode
From: Luis Oliveira <hidden>
Date: 2017-01-17 14:34:12
Also in:
linux-devicetree, lkml
Subsystem:
i2c subsystem, the rest · Maintainers:
Wolfram Sang, Linus Torvalds
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 <redacted> Suggested-by: Andy Shevchenko <redacted> Reviewed-by: Andy Shevchenko <redacted> --- Changes V2->V3: (@Vladimir) - Bug Fix: «of_node_put(child)» added. drivers/i2c/i2c-core.c | 30 ++++++++++++++++++++++++++++++ include/linux/i2c.h | 1 + 2 files changed, 31 insertions(+)
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 583e95042a21..30aa7b50b5bc 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c@@ -3690,6 +3690,36 @@ int i2c_slave_unregister(struct i2c_client *client) return ret; } EXPORT_SYMBOL_GPL(i2c_slave_unregister); + +/** + * i2c_slave_mode_detect - detect operation mode + * @dev: The device owning the bus + * + * This checks the device nodes for an I2C slave by checking the address + * used. + * + * Returns true if an I2C slave is detected, otherwise returns false. + */ +bool i2c_slave_mode_detect(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_slave_mode_detect); + #endif MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 4b45ec46161f..2e72e157826c 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_slave_mode_detect(struct device *dev); static inline int i2c_slave_event(struct i2c_client *client, enum i2c_slave_event event, u8 *val)
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2.11.0