[PATCH 1/1] i2c: added FUNC flag for unsupported clock stretching

[Nicola Corna <nicola-V0pQiMyom5mh6J55Ss3d3w@public.gmane.org>]

Added I2C_FUNC_NO_CLK_STRETCH, to be used when clock stretching is not
supported.
Added this flag to drivers/i2c/algos/i2c-algo-bit.c when getscl is not
available.

Signed-off-by: Nicola Corna <nicola-V0pQiMyom5mh6J55Ss3d3w@public.gmane.org>
---
 Documentation/i2c/functionality  | 1 +
 drivers/i2c/algos/i2c-algo-bit.c | 5 ++++-
 include/uapi/linux/i2c.h         | 1 +
 3 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/Documentation/i2c/functionality b/Documentation/i2c/functionality
index 4aae8ed..f53807e 100644
--- a/Documentation/i2c/functionality
+++ b/Documentation/i2c/functionality
@@ -21,6 +21,7 @@ For the most up-to-date list of functionality constants, please check
                                   I2C_M_REV_DIR_ADDR and I2C_M_NO_RD_ACK
                                   flags (which modify the I2C protocol!)
   I2C_FUNC_NOSTART                Can skip repeated start sequence
+  I2C_FUNC_NO_CLK_STRETCH         Does NOT support clock stretching
   I2C_FUNC_SMBUS_QUICK            Handles the SMBus write_quick command
   I2C_FUNC_SMBUS_READ_BYTE        Handles the SMBus read_byte command
   I2C_FUNC_SMBUS_WRITE_BYTE       Handles the SMBus write_byte command
diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c
index 899bede..82cad0b 100644
--- a/drivers/i2c/algos/i2c-algo-bit.c
+++ b/drivers/i2c/algos/i2c-algo-bit.c
@@ -602,10 +602,13 @@ bailout:
 
 static u32 bit_func(struct i2c_adapter *adap)
 {
+	struct i2c_algo_bit_data *bit_adap = adap->algo_data;
+
 	return I2C_FUNC_I2C | I2C_FUNC_NOSTART | I2C_FUNC_SMBUS_EMUL |
 	       I2C_FUNC_SMBUS_READ_BLOCK_DATA |
 	       I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
-	       I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING;
+	       I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING |
+	       (bit_adap->getscl ? 0 : I2C_FUNC_NO_CLK_STRETCH);
 }
 
 
diff --git a/include/uapi/linux/i2c.h b/include/uapi/linux/i2c.h
index b0a7dd6..59e4b43 100644
--- a/include/uapi/linux/i2c.h
+++ b/include/uapi/linux/i2c.h
@@ -88,6 +88,7 @@ struct i2c_msg {
 #define I2C_FUNC_SMBUS_PEC		0x00000008
 #define I2C_FUNC_NOSTART		0x00000010 /* I2C_M_NOSTART */
 #define I2C_FUNC_SLAVE			0x00000020
+#define I2C_FUNC_NO_CLK_STRETCH		0x00000040 /* No check for SCL low */
 #define I2C_FUNC_SMBUS_BLOCK_PROC_CALL	0x00008000 /* SMBus 2.0 */
 #define I2C_FUNC_SMBUS_QUICK		0x00010000
 #define I2C_FUNC_SMBUS_READ_BYTE	0x00020000
-- 
2.5.0