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| author | Wolfram Sang | 2017-06-19 23:41:46 +0200 |
|---|---|---|
| committer | Wolfram Sang | 2017-06-23 20:30:46 +0200 |
| commit | b395ba21699dbbca2dbf05833a71f5fbf5245a3f (patch) | |
| tree | 50dac13950fa19ad1bef6e9fbf640a43d09ec8c6 /drivers/i2c/busses/i2c-rcar.c | |
| parent | i2c: emev2: Handle return value of clk_prepare_enable (diff) | |
| download | kernel-qcow2-linux-b395ba21699dbbca2dbf05833a71f5fbf5245a3f.tar.gz kernel-qcow2-linux-b395ba21699dbbca2dbf05833a71f5fbf5245a3f.tar.xz kernel-qcow2-linux-b395ba21699dbbca2dbf05833a71f5fbf5245a3f.zip | |
i2c: rcar: document HW incapabilities
Add recent findings (IGNORE_NAK) and document in a bit more detail why
the feature is not possible.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'drivers/i2c/busses/i2c-rcar.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-rcar.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c index 214a71cb6442..030952e2ddc7 100644 --- a/drivers/i2c/busses/i2c-rcar.c +++ b/drivers/i2c/busses/i2c-rcar.c @@ -783,7 +783,12 @@ static int rcar_unreg_slave(struct i2c_client *slave) static u32 rcar_i2c_func(struct i2c_adapter *adap) { - /* This HW can't do SMBUS_QUICK and NOSTART */ + /* + * This HW can't do: + * I2C_SMBUS_QUICK (setting FSB during START didn't work) + * I2C_M_NOSTART (automatically sends address after START) + * I2C_M_IGNORE_NAK (automatically sends STOP after NAK) + */ return I2C_FUNC_I2C | I2C_FUNC_SLAVE | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK); } |