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Commit 4dbfb5f4 authored by Nicola Corna's avatar Nicola Corna Committed by Wolfram Sang
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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: default avatarNicola Corna <nicola@corna.info>
[wsa: put the links into the code as comments]
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent a94d306b

drivers/i2c/busses/i2c-bcm2835.c

+10 −0
Original line number Diff line number Diff line
@@ -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);