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| author | Florian Tobias Schandinat <FlorianSchandinat@gmx.de> | 2010-09-17 03:16:25 +0200 |
|---|---|---|
| committer | Florian Tobias Schandinat <FlorianSchandinat@gmx.de> | 2010-09-24 04:15:11 +0200 |
| commit | 85c5702ac046b14713f776d59768252d8ed8018f (patch) | |
| tree | 0ff48e27730361f9a6b87550766a31605e3cd5eb /drivers/video/via | |
| parent | viafb: vt1636 cleanup (diff) | |
| download | linux-85c5702ac046b14713f776d59768252d8ed8018f.tar.xz linux-85c5702ac046b14713f776d59768252d8ed8018f.zip | |
viafb: fix i2c_transfer error handling
i2c_transfer returns negative errno on error and number of messages
processed on success. Just returning this value would give a poor
interface as it is not obvious that you must compare with 2 after reading
1 or n bytes and with 1 after writing 1 byte to determine if it was
successful. To avoid this error prone interface convert the error code
of a successful read/write to zero and all other non-negative values to
an negative error code.
This fixes a regression introduced by
via: Rationalize vt1636 detection
which resulted in no longer detecting a VT1636 chip and therefore has
broken the output in configurations which contain this chip.
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Cc: Joseph Chan <JosephChan@via.com.tw>
Cc: stable@kernel.org
Diffstat (limited to 'drivers/video/via')
| -rw-r--r-- | drivers/video/via/via_i2c.c | 27 |
1 files changed, 24 insertions, 3 deletions
diff --git a/drivers/video/via/via_i2c.c b/drivers/video/via/via_i2c.c index da9e4ca94b17..021112e279de 100644 --- a/drivers/video/via/via_i2c.c +++ b/drivers/video/via/via_i2c.c @@ -114,6 +114,7 @@ static void via_i2c_setsda(void *data, int state) int viafb_i2c_readbyte(u8 adap, u8 slave_addr, u8 index, u8 *pdata) { + int ret; u8 mm1[] = {0x00}; struct i2c_msg msgs[2]; @@ -126,11 +127,18 @@ int viafb_i2c_readbyte(u8 adap, u8 slave_addr, u8 index, u8 *pdata) mm1[0] = index; msgs[0].len = 1; msgs[1].len = 1; msgs[0].buf = mm1; msgs[1].buf = pdata; - return i2c_transfer(&via_i2c_par[adap].adapter, msgs, 2); + ret = i2c_transfer(&via_i2c_par[adap].adapter, msgs, 2); + if (ret == 2) + ret = 0; + else if (ret >= 0) + ret = -EIO; + + return ret; } int viafb_i2c_writebyte(u8 adap, u8 slave_addr, u8 index, u8 data) { + int ret; u8 msg[2] = { index, data }; struct i2c_msg msgs; @@ -140,11 +148,18 @@ int viafb_i2c_writebyte(u8 adap, u8 slave_addr, u8 index, u8 data) msgs.addr = slave_addr / 2; msgs.len = 2; msgs.buf = msg; - return i2c_transfer(&via_i2c_par[adap].adapter, &msgs, 1); + ret = i2c_transfer(&via_i2c_par[adap].adapter, &msgs, 1); + if (ret == 1) + ret = 0; + else if (ret >= 0) + ret = -EIO; + + return ret; } int viafb_i2c_readbytes(u8 adap, u8 slave_addr, u8 index, u8 *buff, int buff_len) { + int ret; u8 mm1[] = {0x00}; struct i2c_msg msgs[2]; @@ -156,7 +171,13 @@ int viafb_i2c_readbytes(u8 adap, u8 slave_addr, u8 index, u8 *buff, int buff_len mm1[0] = index; msgs[0].len = 1; msgs[1].len = buff_len; msgs[0].buf = mm1; msgs[1].buf = buff; - return i2c_transfer(&via_i2c_par[adap].adapter, msgs, 2); + ret = i2c_transfer(&via_i2c_par[adap].adapter, msgs, 2); + if (ret == 2) + ret = 0; + else if (ret >= 0) + ret = -EIO; + + return ret; } /* |