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drm/radeon/kms: fix i2c prescale calc on older radeons

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Should fix fdo bug 26430

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
This commit is contained in:
Alex Deucher 2010-03-12 12:55:34 -05:00 committed by Dave Airlie
parent ae08819c2a
commit 96a4c8d50d
1 changed files with 8 additions and 9 deletions
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17
drivers/gpu/drm/radeon/radeon_i2c.c
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@ -183,11 +183,10 @@ static void set_data(void *i2c_priv, int data)
static u32 radeon_get_i2c_prescale(struct radeon_device *rdev)
{
struct radeon_pll *spll = &rdev->clock.spll;
u32 sclk = radeon_get_engine_clock(rdev);
u32 prescale = 0;
u32 n, m;
u8 loop;
u32 nm;
u8 n, m, loop;
int i2c_clock;
switch (rdev->family) {
@ -203,13 +202,15 @@ static u32 radeon_get_i2c_prescale(struct radeon_device *rdev)
case CHIP_R300:
case CHIP_R350:
case CHIP_RV350:
n = (spll->reference_freq) / (4 * 6);
i2c_clock = 60;
nm = (sclk * 10) / (i2c_clock * 4);
for (loop = 1; loop < 255; loop++) {
if ((loop * (loop - 1)) > n)
if ((nm / loop) < loop)
break;
}
m = loop - 1;
prescale = m | (loop << 8);
n = loop - 1;
m = loop - 2;
prescale = m | (n << 8);
break;
case CHIP_RV380:
case CHIP_RS400:
@ -217,7 +218,6 @@ static u32 radeon_get_i2c_prescale(struct radeon_device *rdev)
case CHIP_R420:
case CHIP_R423:
case CHIP_RV410:
sclk = radeon_get_engine_clock(rdev);
prescale = (((sclk * 10)/(4 * 128 * 100) + 1) << 8) + 128;
break;
case CHIP_RS600:
@ -232,7 +232,6 @@ static u32 radeon_get_i2c_prescale(struct radeon_device *rdev)
case CHIP_RV570:
case CHIP_R580:
i2c_clock = 50;
sclk = radeon_get_engine_clock(rdev);
if (rdev->family == CHIP_R520)
prescale = (127 << 8) + ((sclk * 10) / (4 * 127 * i2c_clock));
else