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author | Venkateswara Rao Mandela <venkat.mandela@ti.com> | 2018-01-24 13:45:09 +0300 |
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committer | Tomi Valkeinen <tomi.valkeinen@ti.com> | 2018-06-28 13:41:05 +0300 |
commit | c618a3a93b5a118fcf4afe5fe85e83c190f4b127 (patch) | |
tree | 1ddb2cfed00ae62c05e88a59a45fbd1a88524bbe /drivers/gpu/drm/omapdrm/dss/video-pll.c | |
parent | 6ada1328642b8ffc25917c89569d3e16354b43d2 (diff) | |
download | linux-c618a3a93b5a118fcf4afe5fe85e83c190f4b127.tar.xz |
drm/omap: Implement workaround for DRA7 errata ID:i932
Description of DRA7 Errata i932:
In rare circumstances DPLL_VIDEO1 and DPLL_VIDEO2 PLL's may not lock on
the first attempt during DSS initialization. When this occurs, a
subsequent attempt to relock the PLL will result in PLL successfully
locking.
This patch does the following as per the errata recommendation:
- retries locking the PLL upto 20 times.
- The time to wait for a PLL lock set to 1000 REFCLK cycles. We use
usleep_range to wait for 1000 REFCLK cycles in the us range. This tight
constraint is imposed as a lock later than 1000 REFCLK cycles may have
high jitter.
- Criteria for PLL lock is extended from check on just the PLL_LOCK bit
to check on 6 PLL_STATUS bits.
Silicon Versions Impacted:
DRA71, DRA72, DRA74, DRA76 - All silicon revisions
AM57x - All silicon revisions
OMAP4/5 are not impacted by this errata
Signed-off-by: Venkateswara Rao Mandela <venkat.mandela@ti.com>
[tomi.valkeinen@ti.com: ported to v4.14]
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Diffstat (limited to 'drivers/gpu/drm/omapdrm/dss/video-pll.c')
-rw-r--r-- | drivers/gpu/drm/omapdrm/dss/video-pll.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/gpu/drm/omapdrm/dss/video-pll.c b/drivers/gpu/drm/omapdrm/dss/video-pll.c index 585ed94ccf17..cb46311f92c9 100644 --- a/drivers/gpu/drm/omapdrm/dss/video-pll.c +++ b/drivers/gpu/drm/omapdrm/dss/video-pll.c @@ -134,6 +134,7 @@ static const struct dss_pll_hw dss_dra7_video_pll_hw = { .has_refsel = true, .errata_i886 = true, + .errata_i932 = true, }; struct dss_pll *dss_video_pll_init(struct dss_device *dss, |