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imx6: add i2c retries for Ventana /dev/i2c-0

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On Ventana boards the Gateworks System Controller is the only device on I2C1
(/dev/i2c-0) and it can NAK transfers if it is busy in an ADC loop. Because
this is a multi-function device with several slave addresses it is best to
add retries at the controller level instead of within each slave driver. This
adds a patch that adds 3 retries for i2c transactions only for Ventana boards
and only for I2C1

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Signed-off-by: Pushpal Sidhu <psidhu@gateworks.com>

SVN-Revision: 48012
This commit is contained in:
Luka Perkov 2015-12-28 04:56:13 +00:00
parent 158b5b4231
commit 2578f0183c
1 changed files with 24 additions and 0 deletions
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24
target/linux/imx6/patches-4.3/207-i2c-imx-add-retries-for-NAK-s-on-ventana-boards.patch Normal file
View file

@ -0,0 +1,24 @@
Index: linux-4.3/drivers/i2c/busses/i2c-imx.c
===================================================================
--- linux-4.3.orig/drivers/i2c/busses/i2c-imx.c 2015-11-01 16:05:25.000000000 -0800
+++ linux-4.3/drivers/i2c/busses/i2c-imx.c 2015-12-18 10:39:44.971158318 -0800
@@ -461,6 +461,8 @@
{
if (imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR) & I2SR_RXAK) {
dev_dbg(&i2c_imx->adapter.dev, "<%s> No ACK\n", __func__);
+ if (i2c_imx->adapter.retries)
+ return -EAGAIN;
return -EIO; /* No ACK */
}
@@ -1010,6 +1012,10 @@
i2c_imx->adapter.nr = pdev->id;
i2c_imx->adapter.dev.of_node = pdev->dev.of_node;
i2c_imx->base = base;
+ if (of_machine_is_compatible("gw,ventana") && phy_addr == 0x021a0000) {
+ dev_info(&pdev->dev, "Adding retries for Ventana GSC\n");
+ i2c_imx->adapter.retries = 3;
+ }
/* Get I2C clock */
i2c_imx->clk = devm_clk_get(&pdev->dev, NULL);