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authorAlexander Sverdlin <alexander.sverdlin@nokia.com>2015-06-09 13:10:10 +0200
committerWolfram Sang <wsa@the-dreams.de>2015-06-10 15:11:51 +0200
commit41c8d4520461b5134260f3fb9bb56c8455bad610 (patch)
treeaa03498179a2a63183908fc63833cde6dda28220 /drivers/i2c
parenti2c: davinci: Refactor i2c_davinci_wait_bus_not_busy() (diff)
downloadlinux-41c8d4520461b5134260f3fb9bb56c8455bad610.tar.xz
linux-41c8d4520461b5134260f3fb9bb56c8455bad610.zip
i2c: davinci: Avoid sending to own address
Sending a message to own address locks the controller up in very bizarre state, it behaves as slave even if MDR register clearly states master. The controller remains in this state until reset. To avoid unnecessary timeouts simply avoid sending to own address. The controller cannot do this any way. Also, do not enable AAS IRQ, as the slave mode is not supported by the driver and the only possibility to trigger this IRQ is to send to own address. Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'drivers/i2c')
-rw-r--r--drivers/i2c/busses/i2c-davinci.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index ab341aad9038..3d3ae52b6916 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -41,8 +41,8 @@
#define DAVINCI_I2C_TIMEOUT (1*HZ)
#define DAVINCI_I2C_MAX_TRIES 2
-#define I2C_DAVINCI_INTR_ALL (DAVINCI_I2C_IMR_AAS | \
- DAVINCI_I2C_IMR_SCD | \
+#define DAVINCI_I2C_OWN_ADDRESS 0x08
+#define I2C_DAVINCI_INTR_ALL (DAVINCI_I2C_IMR_SCD | \
DAVINCI_I2C_IMR_ARDY | \
DAVINCI_I2C_IMR_NACK | \
DAVINCI_I2C_IMR_AL)
@@ -233,7 +233,7 @@ static int i2c_davinci_init(struct davinci_i2c_dev *dev)
/* Respond at reserved "SMBus Host" slave address" (and zero);
* we seem to have no option to not respond...
*/
- davinci_i2c_write_reg(dev, DAVINCI_I2C_OAR_REG, 0x08);
+ davinci_i2c_write_reg(dev, DAVINCI_I2C_OAR_REG, DAVINCI_I2C_OWN_ADDRESS);
dev_dbg(dev->dev, "PSC = %d\n",
davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG));
@@ -386,6 +386,11 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
u16 w;
unsigned long time_left;
+ if (msg->addr == DAVINCI_I2C_OWN_ADDRESS) {
+ dev_warn(dev->dev, "transfer to own address aborted\n");
+ return -EADDRNOTAVAIL;
+ }
+
/* Introduce a delay, required for some boards (e.g Davinci EVM) */
if (pdata->bus_delay)
udelay(pdata->bus_delay);