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authorHaibo Chen <haibo.chen@freescale.com>2014-09-03 13:52:07 +0800
committerWolfram Sang <wsa@the-dreams.de>2014-09-29 22:41:18 +0200
commit639a26cf0771cb5a4d61a0f7777882cbda989753 (patch)
tree2228ecec63584a220d06028be7f302c75c5750a6 /drivers/i2c/busses/i2c-imx.c
parent29209338b22a61c9ba67badd5f36e96cda1892d8 (diff)
i2c: imx: Add arbitration lost check
According to the i.mx spec, for multimaster mode, if I2C is enabled when the bus is busy and asserts start, hardware inhibits the transmission, clears MSTA without signaling a stop, generate an interrupt, and set I2C_I2SR[IAL] to indicate a failed attempt to engage the bus, which means arbitration lost. In this case, we should first test I2C_I2SR[IAL], and clear this bit if it is set, and then I2C controller default to slave receive mode. This patch check the IAL bit every time before an I2c transmission. if IAL is set, clear it and make I2C controller to default mode. Signed-off-by: Haibo Chen <haibo.chen@freescale.com> Acked-by: Fugang Duan <B38611@freescale.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'drivers/i2c/busses/i2c-imx.c')
-rw-r--r--drivers/i2c/busses/i2c-imx.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index 613069bc561a..ceff87cec18e 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -268,6 +268,14 @@ static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx, int for_busy)
while (1) {
temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
+
+ /* check for arbitration lost */
+ if (temp & I2SR_IAL) {
+ temp &= ~I2SR_IAL;
+ imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR);
+ return -EAGAIN;
+ }
+
if (for_busy && (temp & I2SR_IBB))
break;
if (!for_busy && !(temp & I2SR_IBB))