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>

diff --git a/drivers/gpu/drm/bridge/nwl-dsi.c b/drivers/gpu/drm/bridge/nwl-dsi.c
index a7389a0facfb4e8f4a54607543c40a2e67aec5b0..af07eeb47ca02c5a69e81933d7e17c1ff6876aff 100644 (file)
--- 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);

diff --git a/drivers/phy/amlogic/phy-meson-axg-mipi-dphy.c b/drivers/phy/amlogic/phy-meson-axg-mipi-dphy.c
index cd2332bf0e31ad8d562120343683541435b1bf88..fdbd64c03e12b4efdf2d9e30d22a10d20c47c2f5 100644 (file)
--- a/drivers/phy/amlogic/phy-meson-axg-mipi-dphy.c
+++ b/drivers/phy/amlogic/phy-meson-axg-mipi-dphy.c
@@ -9,6 +9,7 @@
 
 #include <linux/bitfield.h>
 #include <linux/bitops.h>
+#include <linux/bits.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/io.h>
@@ -250,7 +251,7 @@ static int phy_meson_axg_mipi_dphy_power_on(struct phy *phy)
                     (DIV_ROUND_UP(priv->config.clk_zero, temp) << 16) |
                     (DIV_ROUND_UP(priv->config.clk_prepare, temp) << 24));
        regmap_write(priv->regmap, MIPI_DSI_CLK_TIM1,
-                    DIV_ROUND_UP(priv->config.clk_pre, temp));
+                    DIV_ROUND_UP(priv->config.clk_pre, BITS_PER_BYTE));
 
        regmap_write(priv->regmap, MIPI_DSI_HS_TIM,
                     DIV_ROUND_UP(priv->config.hs_exit, temp) |

diff --git a/drivers/phy/phy-core-mipi-dphy.c b/drivers/phy/phy-core-mipi-dphy.c
index 288c9c67aa74872328f48961b247a8c298bc3278..ccb4045685cdd674fed7555bc7be851e90aa96e0 100644 (file)
--- a/drivers/phy/phy-core-mipi-dphy.c
+++ b/drivers/phy/phy-core-mipi-dphy.c
@@ -36,7 +36,7 @@ int phy_mipi_dphy_get_default_config(unsigned long pixel_clock,
 
        cfg->clk_miss = 0;
        cfg->clk_post = 60000 + 52 * ui;
-       cfg->clk_pre = 8000;
+       cfg->clk_pre = 8;
        cfg->clk_prepare = 38000;
        cfg->clk_settle = 95000;
        cfg->clk_term_en = 0;
@@ -97,7 +97,7 @@ int phy_mipi_dphy_config_validate(struct phy_configure_opts_mipi_dphy *cfg)
        if (cfg->clk_post < (60000 + 52 * ui))
                return -EINVAL;
 
-       if (cfg->clk_pre < 8000)
+       if (cfg->clk_pre < 8)
                return -EINVAL;
 
        if (cfg->clk_prepare < 38000 || cfg->clk_prepare > 95000)

diff --git a/drivers/phy/rockchip/phy-rockchip-inno-dsidphy.c b/drivers/phy/rockchip/phy-rockchip-inno-dsidphy.c
index 347dc79a18c18a6f235bc47c89b4b861cdd0c60a..630e01b5c19b9543d1f9afb8af4216dfad4b40c3 100644 (file)
--- a/drivers/phy/rockchip/phy-rockchip-inno-dsidphy.c
+++ b/drivers/phy/rockchip/phy-rockchip-inno-dsidphy.c
@@ -5,6 +5,7 @@
  * Author: Wyon Bi <bivvy.bi@rock-chips.com>
  */
 
+#include <linux/bits.h>
 #include <linux/kernel.h>
 #include <linux/clk.h>
 #include <linux/iopoll.h>
@@ -364,7 +365,7 @@ static void inno_dsidphy_mipi_mode_enable(struct inno_dsidphy *inno)
         * The value of counter for HS Tclk-pre
         * Tclk-pre = Tpin_txbyteclkhs * value
         */
-       clk_pre = DIV_ROUND_UP(cfg->clk_pre, t_txbyteclkhs);
+       clk_pre = DIV_ROUND_UP(cfg->clk_pre, BITS_PER_BYTE);
 
        /*
         * The value of counter for HS Tlpx Time