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| author | Nicola Corna <nicola@corna.info> | 2015-10-29 12:34:25 +0100 |
|---|---|---|
| committer | Wolfram Sang <wsa@the-dreams.de> | 2015-11-30 18:37:26 +0100 |
| commit | 4dbfb5f4401f845903679afbfeb4b97b47bb2331 (patch) | |
| tree | 54f701da0af1ac54954f4ee8d3baad48dadab4a7 /drivers/i2c | |
| parent | a94d306b71a5202cb928a7a1328dedab4fe0e968 (diff) | |
| download | linux-stable-4dbfb5f4401f845903679afbfeb4b97b47bb2331.tar.gz linux-stable-4dbfb5f4401f845903679afbfeb4b97b47bb2331.tar.bz2 linux-stable-4dbfb5f4401f845903679afbfeb4b97b47bb2331.zip | |
i2c: bcm2835: add I2C_AQ_NO_CLK_STRETCH
As reported in the links given below. the BCM2835 has a hardware bug in
its i2c module which prevents a correct clock stretching. This patch
adds the I2C_AQ_NO_CLK_STRETCH quirk flag to i2c-bcm2835.
Signed-off-by: Nicola Corna <nicola@corna.info>
[wsa: put the links into the code as comments]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/busses/i2c-bcm2835.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-bcm2835.c b/drivers/i2c/busses/i2c-bcm2835.c index 3032b89ac60b..818b051d25e6 100644 --- a/drivers/i2c/busses/i2c-bcm2835.c +++ b/drivers/i2c/busses/i2c-bcm2835.c @@ -222,6 +222,15 @@ static const struct i2c_algorithm bcm2835_i2c_algo = { .functionality = bcm2835_i2c_func, }; +/* + * This HW was reported to have problems with clock stretching: + * http://www.advamation.com/knowhow/raspberrypi/rpi-i2c-bug.html + * https://www.raspberrypi.org/forums/viewtopic.php?p=146272 + */ +static const struct i2c_adapter_quirks bcm2835_i2c_quirks = { + .flags = I2C_AQ_NO_CLK_STRETCH, +}; + static int bcm2835_i2c_probe(struct platform_device *pdev) { struct bcm2835_i2c_dev *i2c_dev; @@ -293,6 +302,7 @@ static int bcm2835_i2c_probe(struct platform_device *pdev) adap->algo = &bcm2835_i2c_algo; adap->dev.parent = &pdev->dev; adap->dev.of_node = pdev->dev.of_node; + adap->quirks = &bcm2835_i2c_quirks; bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_C, 0); |