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drm/radeon: atombios hw i2c fixes

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These fixes make writes work properly.  Previously
only reads worked.  Note that this feature is off
by default.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Alex Deucher 2013-08-21 13:48:12 -04:00
parent 95663948ba
commit d1e3b55648
1 changed files with 8 additions and 4 deletions
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12
drivers/gpu/drm/radeon/atombios_i2c.c
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@ -32,7 +32,7 @@ extern void radeon_atom_copy_swap(u8 *dst, u8 *src, u8 num_bytes, bool to_le);
#define TARGET_HW_I2C_CLOCK 50
/* these are a limitation of ProcessI2cChannelTransaction not the hw */
#define ATOM_MAX_HW_I2C_WRITE 2
#define ATOM_MAX_HW_I2C_WRITE 3
#define ATOM_MAX_HW_I2C_READ 255
static int radeon_process_i2c_ch(struct radeon_i2c_chan *chan,
@ -52,20 +52,24 @@ static int radeon_process_i2c_ch(struct radeon_i2c_chan *chan,
if (flags & HW_I2C_WRITE) {
if (num > ATOM_MAX_HW_I2C_WRITE) {
DRM_ERROR("hw i2c: tried to write too many bytes (%d vs 2)\n", num);
DRM_ERROR("hw i2c: tried to write too many bytes (%d vs 3)\n", num);
return -EINVAL;
}
memcpy(&out, buf, num);
args.ucRegIndex = buf[0];
if (num > 1)
memcpy(&out, &buf[1], num - 1);
args.lpI2CDataOut = cpu_to_le16(out);
} else {
if (num > ATOM_MAX_HW_I2C_READ) {
DRM_ERROR("hw i2c: tried to read too many bytes (%d vs 255)\n", num);
return -EINVAL;
}
args.ucRegIndex = 0;
args.lpI2CDataOut = 0;
}
args.ucFlag = flags;
args.ucI2CSpeed = TARGET_HW_I2C_CLOCK;
args.ucRegIndex = 0;
args.ucTransBytes = num;
args.ucSlaveAddr = slave_addr << 1;
args.ucLineNumber = chan->rec.i2c_id;