i2c: Add an interface to lock/unlock an I2C bus segment
Some drivers need to be able to prevent access to an I2C bus segment
for a specific period of time. Add an interface for them to do so
without twiddling with i2c-core internals.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Ben Hutchings <bhutchings@solarflare.com>
diff --git a/drivers/net/sfc/sfe4001.c b/drivers/net/sfc/sfe4001.c
index cee00ad..49eb91b 100644
--- a/drivers/net/sfc/sfe4001.c
+++ b/drivers/net/sfc/sfe4001.c
@@ -188,7 +188,7 @@
efx_oword_t reg;
/* GPIO 3 and the GPIO register are shared with I2C, so block that */
- mutex_lock(&efx->i2c_adap.bus_lock);
+ i2c_lock_adapter(&efx->i2c_adap);
/* Pull RST_N (GPIO 2) low then let it up again, setting the
* FLASH_CFG_1 strap (GPIO 3) appropriately. Only change the
@@ -204,7 +204,7 @@
falcon_write(efx, ®, GPIO_CTL_REG_KER);
msleep(1);
- mutex_unlock(&efx->i2c_adap.bus_lock);
+ i2c_unlock_adapter(&efx->i2c_adap);
ssleep(1);
return 0;
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 57d41b0..7b40cda 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -361,6 +361,24 @@
dev_set_drvdata(&dev->dev, data);
}
+/**
+ * i2c_lock_adapter - Prevent access to an I2C bus segment
+ * @adapter: Target I2C bus segment
+ */
+static inline void i2c_lock_adapter(struct i2c_adapter *adapter)
+{
+ mutex_lock(&adapter->bus_lock);
+}
+
+/**
+ * i2c_unlock_adapter - Reauthorize access to an I2C bus segment
+ * @adapter: Target I2C bus segment
+ */
+static inline void i2c_unlock_adapter(struct i2c_adapter *adapter)
+{
+ mutex_unlock(&adapter->bus_lock);
+}
+
/*flags for the client struct: */
#define I2C_CLIENT_PEC 0x04 /* Use Packet Error Checking */
#define I2C_CLIENT_TEN 0x10 /* we have a ten bit chip address */