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authorAlex Deucher <alexdeucher@gmail.com>2011-04-17 10:20:19 +0200
committerJean Delvare <khali@endymion.delvare>2011-04-17 10:20:19 +0200
commitd3b3e15da14ded61c9654db05863b04a2435f4cc (patch)
treec683f167f9e8049201773e4b2884d40cc30a4fd3
parenta920ff41cb3d2b03da095c4fa1a11b71417ae2a4 (diff)
downloadlinux-linaro-d3b3e15da14ded61c9654db05863b04a2435f4cc.tar.gz
i2c-algo-bit: Call pre/post_xfer for bit_test
Apparently some distros set i2c-algo-bit.bit_test to 1 by default. In some cases this causes i2c_bit_add_bus to fail and prevents the i2c bus from being added. In the radeon case, we fail to add the ddc i2c buses which prevents the driver from being able to detect attached monitors. The i2c bus works fine even if bit_test fails. This is likely due to gpio switching that is required and handled in the pre/post_xfer hooks, so call the pre/post_xfer hooks in the bit test as well. Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=36221 Signed-off-by: Alex Deucher <alexdeucher@gmail.com> Signed-off-by: Jean Delvare <khali@linux-fr.org> Cc: stable@kernel.org [.38 down to .34]
-rw-r--r--drivers/i2c/algos/i2c-algo-bit.c22
1 files changed, 19 insertions, 3 deletions
diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c
index 38319a69bd0..d6d58684712 100644
--- a/drivers/i2c/algos/i2c-algo-bit.c
+++ b/drivers/i2c/algos/i2c-algo-bit.c
@@ -232,9 +232,17 @@ static int i2c_inb(struct i2c_adapter *i2c_adap)
* Sanity check for the adapter hardware - check the reaction of
* the bus lines only if it seems to be idle.
*/
-static int test_bus(struct i2c_algo_bit_data *adap, char *name)
+static int test_bus(struct i2c_adapter *i2c_adap)
{
- int scl, sda;
+ struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
+ const char *name = i2c_adap->name;
+ int scl, sda, ret;
+
+ if (adap->pre_xfer) {
+ ret = adap->pre_xfer(i2c_adap);
+ if (ret < 0)
+ return -ENODEV;
+ }
if (adap->getscl == NULL)
pr_info("%s: Testing SDA only, SCL is not readable\n", name);
@@ -297,11 +305,19 @@ static int test_bus(struct i2c_algo_bit_data *adap, char *name)
"while pulling SCL high!\n", name);
goto bailout;
}
+
+ if (adap->post_xfer)
+ adap->post_xfer(i2c_adap);
+
pr_info("%s: Test OK\n", name);
return 0;
bailout:
sdahi(adap);
sclhi(adap);
+
+ if (adap->post_xfer)
+ adap->post_xfer(i2c_adap);
+
return -ENODEV;
}
@@ -607,7 +623,7 @@ static int __i2c_bit_add_bus(struct i2c_adapter *adap,
int ret;
if (bit_test) {
- ret = test_bus(bit_adap, adap->name);
+ ret = test_bus(adap);
if (ret < 0)
return -ENODEV;
}