diff options
| author | Liu Ying <victor.liu@nxp.com> | 2022-01-24 05:40:07 +0300 |
|---|---|---|
| committer | Vinod Koul <vkoul@kernel.org> | 2022-02-02 08:03:04 +0300 |
| commit | 9a8406ba1a9a2965c27e0db1d7753471d12ee9ff (patch) | |
| tree | 2fceeab99e34a3b57eb2f930866ff402ea2fa372 /drivers/gpu/drm | |
| parent | 46e994717807f4b935c44d81dde9dd8bcd9a4f5d (diff) | |
| download | linux-9a8406ba1a9a2965c27e0db1d7753471d12ee9ff.tar.xz | |
phy: dphy: Correct clk_pre parameter
The D-PHY specification (v1.2) explicitly mentions that the T-CLK-PRE
parameter's unit is Unit Interval(UI) and the minimum value is 8. Also,
kernel doc of the 'clk_pre' member of struct phy_configure_opts_mipi_dphy
mentions that it should be in UI. However, the dphy core driver wrongly
sets 'clk_pre' to 8000, which seems to hint that it's in picoseconds.
So, let's fix the dphy core driver to correctly reflect the T-CLK-PRE
parameter's minimum value according to the D-PHY specification.
I'm assuming that all impacted custom drivers shall program values in
TxByteClkHS cycles into hardware for the T-CLK-PRE parameter. The D-PHY
specification mentions that the frequency of TxByteClkHS is exactly 1/8
the High-Speed(HS) bit rate(each HS bit consumes one UI). So, relevant
custom driver code is changed to program those values as
DIV_ROUND_UP(cfg->clk_pre, BITS_PER_BYTE), then.
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: 2ed869990e14 ("phy: Add MIPI D-PHY configuration options")
Tested-by: Liu Ying <victor.liu@nxp.com> # RM67191 DSI panel on i.MX8mq EVK
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com> # for phy-meson-axg-mipi-dphy.c
Tested-by: Neil Armstrong <narmstrong@baylibre.com> # for phy-meson-axg-mipi-dphy.c
Tested-by: Guido Günther <agx@sigxcpu.org> # Librem 5 (imx8mq) with it's rather picky panel
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Liu Ying <victor.liu@nxp.com>
Link: https://lore.kernel.org/r/20220124024007.1465018-1-victor.liu@nxp.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'drivers/gpu/drm')
| -rw-r--r-- | drivers/gpu/drm/bridge/nwl-dsi.c | 12 |
1 files changed, 5 insertions, 7 deletions
diff --git a/drivers/gpu/drm/bridge/nwl-dsi.c b/drivers/gpu/drm/bridge/nwl-dsi.c index a7389a0facfb..af07eeb47ca0 100644 --- a/drivers/gpu/drm/bridge/nwl-dsi.c +++ b/drivers/gpu/drm/bridge/nwl-dsi.c @@ -7,6 +7,7 @@ */ #include <linux/bitfield.h> +#include <linux/bits.h> #include <linux/clk.h> #include <linux/irq.h> #include <linux/math64.h> @@ -196,12 +197,9 @@ static u32 ps2bc(struct nwl_dsi *dsi, unsigned long long ps) /* * ui2bc - UI time periods to byte clock cycles */ -static u32 ui2bc(struct nwl_dsi *dsi, unsigned long long ui) +static u32 ui2bc(unsigned int ui) { - u32 bpp = mipi_dsi_pixel_format_to_bpp(dsi->format); - - return DIV64_U64_ROUND_UP(ui * dsi->lanes, - dsi->mode.clock * 1000 * bpp); + return DIV_ROUND_UP(ui, BITS_PER_BYTE); } /* @@ -232,12 +230,12 @@ static int nwl_dsi_config_host(struct nwl_dsi *dsi) } /* values in byte clock cycles */ - cycles = ui2bc(dsi, cfg->clk_pre); + cycles = ui2bc(cfg->clk_pre); DRM_DEV_DEBUG_DRIVER(dsi->dev, "cfg_t_pre: 0x%x\n", cycles); nwl_dsi_write(dsi, NWL_DSI_CFG_T_PRE, cycles); cycles = ps2bc(dsi, cfg->lpx + cfg->clk_prepare + cfg->clk_zero); DRM_DEV_DEBUG_DRIVER(dsi->dev, "cfg_tx_gap (pre): 0x%x\n", cycles); - cycles += ui2bc(dsi, cfg->clk_pre); + cycles += ui2bc(cfg->clk_pre); DRM_DEV_DEBUG_DRIVER(dsi->dev, "cfg_t_post: 0x%x\n", cycles); nwl_dsi_write(dsi, NWL_DSI_CFG_T_POST, cycles); cycles = ps2bc(dsi, cfg->hs_exit); |