From d3b3e15da14ded61c9654db05863b04a2435f4cc Mon Sep 17 00:00:00 2001 From: Alex Deucher Date: Sun, 17 Apr 2011 10:20:19 +0200 Subject: [PATCH] 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 Signed-off-by: Jean Delvare Cc: stable@kernel.org [.38 down to .34] --- drivers/i2c/algos/i2c-algo-bit.c | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c index 38319a6..d6d5868 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; } -- 2.7.4