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| author | Liu Ying <victor.liu@nxp.com> | 2022-02-16 10:12:57 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-04-08 15:23:46 +0300 |
| commit | d9a3c2949d04715f802c10351efbee940e4c9f7a (patch) | |
| tree | a546fd041bc2a0351d1f72b9a9441e27cb9e406c /drivers/phy | |
| parent | ca3d7cf53d8f6e83759afc25cf763888a07a8b33 (diff) | |
| download | linux-d9a3c2949d04715f802c10351efbee940e4c9f7a.tar.xz | |
phy: dphy: Correct lpx parameter and its derivatives(ta_{get,go,sure})
[ Upstream commit 3153fa38e38af566cf6454a03b1dbadaf6f323c0 ]
According to the comment of the function phy_mipi_dphy_get_default_config(),
it uses minimum D-PHY timings based on MIPI D-PHY specification. They are
derived from the valid ranges specified in Section 6.9, Table 14, Page 41
of the D-PHY specification (v1.2). The table 14 explicitly mentions that
the minimum T-LPX parameter is 50 nanoseconds and the minimum TA-SURE
parameter is T-LPX nanoseconds. Likewise, the kernel doc of the 'lpx' and
'ta_sure' members of struct phy_configure_opts_mipi_dphy mentions that
the minimum values are 50000 picoseconds and @lpx picoseconds respectively.
Also, the function phy_mipi_dphy_config_validate() checks if cfg->lpx is
less than 50000 picoseconds and if cfg->ta_sure is less than cfg->lpx,
which hints the same minimum values.
Without this patch, the function phy_mipi_dphy_get_default_config()
wrongly sets cfg->lpx to 60000 picoseconds and cfg->ta_sure to 2 * cfg->lpx.
So, let's correct them to 50000 picoseconds and cfg->lpx respectively.
Note that I've only tested the patch with RM67191 DSI panel on i.MX8mq EVK.
Help is needed to test with other i.MX8mq, Meson and Rockchip platforms,
as I don't have the hardwares.
Fixes: dddc97e82303 ("phy: dphy: Add configuration helpers")
Cc: Andrzej Hajda <andrzej.hajda@intel.com>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Cc: Laurent Pinchart <Laurent.pinchart@ideasonboard.com>
Cc: Kishon Vijay Abraham I <kishon@ti.com>
Cc: Vinod Koul <vkoul@kernel.org>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Guido Günther <agx@sigxcpu.org>
Signed-off-by: Liu Ying <victor.liu@nxp.com>
Link: https://lore.kernel.org/r/20220216071257.1647703-1-victor.liu@nxp.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/phy')
| -rw-r--r-- | drivers/phy/phy-core-mipi-dphy.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/phy/phy-core-mipi-dphy.c b/drivers/phy/phy-core-mipi-dphy.c index ccb4045685cd..929e86d6558e 100644 --- a/drivers/phy/phy-core-mipi-dphy.c +++ b/drivers/phy/phy-core-mipi-dphy.c @@ -64,10 +64,10 @@ int phy_mipi_dphy_get_default_config(unsigned long pixel_clock, cfg->hs_trail = max(4 * 8 * ui, 60000 + 4 * 4 * ui); cfg->init = 100; - cfg->lpx = 60000; + cfg->lpx = 50000; cfg->ta_get = 5 * cfg->lpx; cfg->ta_go = 4 * cfg->lpx; - cfg->ta_sure = 2 * cfg->lpx; + cfg->ta_sure = cfg->lpx; cfg->wakeup = 1000; cfg->hs_clk_rate = hs_clk_rate; |