This mipi dsi host driver is based on the Rockchip version of the
Synopsys Designware mipi dsi driver (rockchip/dw-mipi-dsi.c)
modified for the stm32 family:
- replace Rockchip digital & phy specific extensions with stm32's ones.
- add a bridge

Signed-off-by: Philippe CORNU <philippe.co...@st.com>
---
 drivers/gpu/drm/stm/Kconfig       |    7 +
 drivers/gpu/drm/stm/Makefile      |    2 +
 drivers/gpu/drm/stm/dw-mipi-dsi.c | 1197 +++++++++++++++++++++++++++++++++++++
 3 files changed, 1206 insertions(+)
 create mode 100644 drivers/gpu/drm/stm/dw-mipi-dsi.c

diff --git a/drivers/gpu/drm/stm/Kconfig b/drivers/gpu/drm/stm/Kconfig
index 2c4817f..0007789 100644
--- a/drivers/gpu/drm/stm/Kconfig
+++ b/drivers/gpu/drm/stm/Kconfig
@@ -14,3 +14,10 @@ config DRM_STM
          STMicroelectronics STM32 MCUs.
          To compile this driver as a module, choose M here: the module
          will be called stm-drm.
+
+config DRM_STM_DSI
+       tristate "MIPI DSI support for STMicroelectronics SoC"
+       depends on DRM_STM
+       select DRM_MIPI_DSI
+       help
+         Choose this option for MIPI DSI support on STMicroelectronics SoC.
diff --git a/drivers/gpu/drm/stm/Makefile b/drivers/gpu/drm/stm/Makefile
index e114d45..e448a93 100644
--- a/drivers/gpu/drm/stm/Makefile
+++ b/drivers/gpu/drm/stm/Makefile
@@ -4,4 +4,6 @@ stm-drm-y := \
        drv.o \
        ltdc.o
 
+obj-$(CONFIG_DRM_STM_DSI) += dw-mipi-dsi.o
+
 obj-$(CONFIG_DRM_STM) += stm-drm.o
diff --git a/drivers/gpu/drm/stm/dw-mipi-dsi.c 
b/drivers/gpu/drm/stm/dw-mipi-dsi.c
new file mode 100644
index 0000000..4b7f7b9
--- /dev/null
+++ b/drivers/gpu/drm/stm/dw-mipi-dsi.c
@@ -0,0 +1,1197 @@
+/*
+ * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Modified by Philippe Cornu <philippe.co...@st.com> for the stm32 family.
+ */
+#include <linux/clk.h>
+#include <linux/component.h>
+#include <linux/iopoll.h>
+#include <linux/math64.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+#include <linux/mfd/syscon.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_crtc.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_mipi_dsi.h>
+#include <drm/drm_of.h>
+#include <drm/drm_panel.h>
+#include <drm/drmP.h>
+#include <video/mipi_display.h>
+
+#define DRIVER_NAME    "dw-mipi-dsi"
+
+#define DSI_VERSION                    0x00
+#define DSI_PWR_UP                     0x04
+#define RESET                          0
+#define POWERUP                                BIT(0)
+
+#define DSI_CLKMGR_CFG                 0x08
+#define TO_CLK_DIVIDSION(div)          (((div) & 0xff) << 8)
+#define TX_ESC_CLK_DIVIDSION(div)      (((div) & 0xff) << 0)
+
+#define DSI_DPI_VCID                   0x0c
+#define DPI_VID(vid)                   (((vid) & 0x3) << 0)
+
+#define DSI_DPI_COLOR_CODING           0x10
+#define EN18_LOOSELY                   BIT(8)
+#define DPI_COLOR_CODING_16BIT_1       0x0
+#define DPI_COLOR_CODING_16BIT_2       0x1
+#define DPI_COLOR_CODING_16BIT_3       0x2
+#define DPI_COLOR_CODING_18BIT_1       0x3
+#define DPI_COLOR_CODING_18BIT_2       0x4
+#define DPI_COLOR_CODING_24BIT         0x5
+
+#define DSI_DPI_CFG_POL                        0x14
+#define COLORM_ACTIVE_LOW              BIT(4)
+#define SHUTD_ACTIVE_LOW               BIT(3)
+#define HSYNC_ACTIVE_LOW               BIT(2)
+#define VSYNC_ACTIVE_LOW               BIT(1)
+#define DATAEN_ACTIVE_LOW              BIT(0)
+
+#define DSI_DPI_LP_CMD_TIM             0x18
+#define OUTVACT_LPCMD_TIME(p)          (((p) & 0xff) << 16)
+#define INVACT_LPCMD_TIME(p)           ((p) & 0xff)
+
+#define DSI_DBI_CFG                    0x20
+#define DSI_DBI_CMDSIZE                        0x28
+
+#define DSI_PCKHDL_CFG                 0x2c
+#define EN_CRC_RX                      BIT(4)
+#define EN_ECC_RX                      BIT(3)
+#define EN_BTA                         BIT(2)
+#define EN_EOTP_RX                     BIT(1)
+#define EN_EOTP_TX                     BIT(0)
+
+#define DSI_MODE_CFG                   0x34
+#define ENABLE_VIDEO_MODE              0
+#define ENABLE_CMD_MODE                        BIT(0)
+
+#define DSI_VID_MODE_CFG               0x38
+#define FRAME_BTA_ACK                  BIT(14)
+#define ENABLE_LOW_POWER               (0x3f << 8)
+#define ENABLE_LOW_POWER_MASK          (0x3f << 8)
+#define VID_MODE_TYPE_NON_BURST_SYNC_PULSES    0x0
+#define VID_MODE_TYPE_NON_BURST_SYNC_EVENTS    0x1
+#define VID_MODE_TYPE_BURST                    0x2
+#define VID_MODE_TYPE_MASK                     0x3
+
+#define DSI_VID_PKT_SIZE               0x3c
+#define VID_PKT_SIZE(p)                        (((p) & 0x3fff) << 0)
+#define VID_PKT_MAX_SIZE               0x3fff
+
+#define DSI_VID_HSA_TIME               0x48
+#define DSI_VID_HBP_TIME               0x4c
+#define DSI_VID_HLINE_TIME             0x50
+#define DSI_VID_VSA_LINES              0x54
+#define DSI_VID_VBP_LINES              0x58
+#define DSI_VID_VFP_LINES              0x5c
+#define DSI_VID_VACTIVE_LINES          0x60
+#define DSI_CMD_MODE_CFG               0x68
+#define MAX_RD_PKT_SIZE_LP             BIT(24)
+#define DCS_LW_TX_LP                   BIT(19)
+#define DCS_SR_0P_TX_LP                        BIT(18)
+#define DCS_SW_1P_TX_LP                        BIT(17)
+#define DCS_SW_0P_TX_LP                        BIT(16)
+#define GEN_LW_TX_LP                   BIT(14)
+#define GEN_SR_2P_TX_LP                        BIT(13)
+#define GEN_SR_1P_TX_LP                        BIT(12)
+#define GEN_SR_0P_TX_LP                        BIT(11)
+#define GEN_SW_2P_TX_LP                        BIT(10)
+#define GEN_SW_1P_TX_LP                        BIT(9)
+#define GEN_SW_0P_TX_LP                        BIT(8)
+#define EN_ACK_RQST                    BIT(1)
+#define EN_TEAR_FX                     BIT(0)
+
+#define CMD_MODE_ALL_LP                        (MAX_RD_PKT_SIZE_LP | \
+                                        DCS_LW_TX_LP | \
+                                        DCS_SR_0P_TX_LP | \
+                                        DCS_SW_1P_TX_LP | \
+                                        DCS_SW_0P_TX_LP | \
+                                        GEN_LW_TX_LP | \
+                                        GEN_SR_2P_TX_LP | \
+                                        GEN_SR_1P_TX_LP | \
+                                        GEN_SR_0P_TX_LP | \
+                                        GEN_SW_2P_TX_LP | \
+                                        GEN_SW_1P_TX_LP | \
+                                        GEN_SW_0P_TX_LP)
+
+#define DSI_GEN_HDR                    0x6c
+#define GEN_HDATA(data)                        (((data) & 0xffff) << 8)
+#define GEN_HDATA_MASK                 (0xffff << 8)
+#define GEN_HTYPE(type)                        (((type) & 0xff) << 0)
+#define GEN_HTYPE_MASK                 0xff
+
+#define DSI_GEN_PLD_DATA               0x70
+
+#define DSI_CMD_PKT_STATUS             0x74
+#define GEN_CMD_EMPTY                  BIT(0)
+#define GEN_CMD_FULL                   BIT(1)
+#define GEN_PLD_W_EMPTY                        BIT(2)
+#define GEN_PLD_W_FULL                 BIT(3)
+#define GEN_PLD_R_EMPTY                        BIT(4)
+#define GEN_PLD_R_FULL                 BIT(5)
+#define GEN_RD_CMD_BUSY                        BIT(6)
+
+#define DSI_TO_CNT_CFG                 0x78
+#define HSTX_TO_CNT(p)                 (((p) & 0xffff) << 16)
+#define LPRX_TO_CNT(p)                 ((p) & 0xffff)
+
+#define DSI_BTA_TO_CNT                 0x8c
+#define DSI_LPCLK_CTRL                 0x94
+#define AUTO_CLKLANE_CTRL              BIT(1)
+#define PHY_TXREQUESTCLKHS             BIT(0)
+
+#define DSI_PHY_TMR_LPCLK_CFG          0x98
+#define PHY_CLKHS2LP_TIME(lbcc)                (((lbcc) & 0x3ff) << 16)
+#define PHY_CLKLP2HS_TIME(lbcc)                ((lbcc) & 0x3ff)
+
+#define DSI_PHY_TMR_CFG                        0x9c
+#define PHY_HS2LP_TIME(lbcc)           (((lbcc) & 0xff) << 24)
+#define PHY_LP2HS_TIME(lbcc)           (((lbcc) & 0xff) << 16)
+#define MAX_RD_TIME(lbcc)              ((lbcc) & 0x7fff)
+
+#define DSI_PHY_RSTZ                   0xa0
+#define PHY_DISFORCEPLL                        0
+#define PHY_ENFORCEPLL                 BIT(3)
+#define PHY_DISABLECLK                 0
+#define PHY_ENABLECLK                  BIT(2)
+#define PHY_RSTZ                       0
+#define PHY_UNRSTZ                     BIT(1)
+#define PHY_SHUTDOWNZ                  0
+#define PHY_UNSHUTDOWNZ                        BIT(0)
+
+#define DSI_PHY_IF_CFG                 0xa4
+#define N_LANES(n)                     ((((n) - 1) & 0x3) << 0)
+#define PHY_STOP_WAIT_TIME(cycle)      (((cycle) & 0xff) << 8)
+
+#define DSI_PHY_STATUS                 0xb0
+#define LOCK                           BIT(0)
+#define STOP_STATE_CLK_LANE            BIT(2)
+
+#define DSI_PHY_TST_CTRL0              0xb4
+#define PHY_TESTCLK                    BIT(1)
+#define PHY_UNTESTCLK                  0
+#define PHY_TESTCLR                    BIT(0)
+#define PHY_UNTESTCLR                  0
+
+#define DSI_PHY_TST_CTRL1              0xb8
+#define PHY_TESTEN                     BIT(16)
+#define PHY_UNTESTEN                   0
+#define PHY_TESTDOUT(n)                        (((n) & 0xff) << 8)
+#define PHY_TESTDIN(n)                 (((n) & 0xff) << 0)
+
+#define DSI_INT_ST0                    0xbc
+#define DSI_INT_ST1                    0xc0
+#define DSI_INT_MSK0                   0xc4
+#define DSI_INT_MSK1                   0xc8
+
+#define PHY_STATUS_TIMEOUT_US          10000
+#define CMD_PKT_STATUS_TIMEOUT_US      20000
+
+/* DSI wrapper register & bit definitions */
+/* Note: registers are named as in the Reference Manual */
+#define DSI_WCFGR      0x0400          /* Wrapper ConFiGuration Reg */
+#define WCFGR_DSIM     BIT(0)          /* DSI Mode */
+#define WCFGR_COLMUX   GENMASK(3, 1)   /* COLor MUltipleXing */
+
+#define DSI_WCR                0x0404          /* Wrapper Control Reg */
+#define WCR_DSIEN      BIT(3)          /* DSI ENable */
+
+#define DSI_WISR       0x040C          /* Wrapper Interrupt and Status Reg */
+#define WISR_PLLLS     BIT(8)          /* PLL Lock Status */
+#define WISR_RRS       BIT(12)         /* Regulator Ready Status */
+
+#define DSI_WPCR0      0x0418          /* Wrapper Phy Conf Reg 0 */
+#define WPCR0_UIX4     GENMASK(5, 0)   /* Unit Interval X 4 */
+#define WPCR0_TDDL     BIT(16)         /* Turn Disable Data Lanes */
+
+#define DSI_WRPCR      0x0430          /* Wrapper Regulator & Pll Ctrl Reg */
+#define WRPCR_PLLEN    BIT(0)          /* PLL ENable */
+#define WRPCR_NDIV     GENMASK(8, 2)   /* pll loop DIVision Factor */
+#define WRPCR_IDF      GENMASK(14, 11) /* pll Input Division Factor */
+#define WRPCR_ODF      GENMASK(17, 16) /* pll Output Division Factor */
+#define WRPCR_REGEN    BIT(24)         /* REGulator ENable */
+#define WRPCR_BGREN    BIT(28)         /* BandGap Reference ENable */
+#define IDF_MIN                1
+#define IDF_MAX                7
+#define NDIV_MIN       10
+#define NDIV_MAX       125
+#define ODF_MIN                1
+#define ODF_MAX                8
+
+/* dsi color format coding according to the datasheet */
+enum dsi_color {
+       DSI_RGB565_CONF1, DSI_RGB565_CONF2, DSI_RGB565_CONF3,
+       DSI_RGB666_CONF1, DSI_RGB666_CONF2,
+       DSI_RGB888,
+};
+
+#define LANE_MIN_KBPS  31250
+#define LANE_MAX_KBPS  500000
+
+/* Sleep & timeout for regulator on/off, pll lock/unlock & fifo empty */
+#define SLEEP_US       1000
+#define TIMEOUT_US     200000
+
+struct dw_mipi_dsi_plat_data {
+       unsigned int max_data_lanes;
+};
+
+struct dw_mipi_dsi {
+       struct drm_bridge bridge;
+       struct drm_connector connector;
+       struct mipi_dsi_host dsi_host;
+       struct drm_panel *panel;
+       struct device *dev;
+       struct regmap *grf_regmap;
+       void __iomem *base;
+
+       struct clk *pllref_clk;
+       struct clk *pclk;
+
+       int dpms_mode;
+       unsigned int lane_mbps; /* per lane */
+       u32 channel;
+       u32 lanes;
+       u32 format;
+       unsigned long mode_flags;
+
+       const struct dw_mipi_dsi_plat_data *pdata;
+};
+
+enum dw_mipi_dsi_mode {
+       DW_MIPI_DSI_CMD_MODE,
+       DW_MIPI_DSI_VID_MODE,
+};
+
+/*
+ * The controller should generate 2 frames before
+ * preparing the peripheral.
+ */
+static void dw_mipi_dsi_wait_for_two_frames(struct drm_display_mode *mode)
+{
+       int refresh, two_frames;
+
+       refresh = drm_mode_vrefresh(mode);
+       two_frames = DIV_ROUND_UP(MSEC_PER_SEC, refresh) * 2;
+       msleep(two_frames);
+}
+
+static inline struct dw_mipi_dsi *host_to_dsi(struct mipi_dsi_host *host)
+{
+       return container_of(host, struct dw_mipi_dsi, dsi_host);
+}
+
+static inline struct dw_mipi_dsi *con_to_dsi(struct drm_connector *con)
+{
+       return container_of(con, struct dw_mipi_dsi, connector);
+}
+
+static inline struct dw_mipi_dsi *bridge_to_dsi(struct drm_bridge *bridge)
+{
+       return container_of(bridge, struct dw_mipi_dsi, bridge);
+}
+
+static inline void dsi_write(struct dw_mipi_dsi *dsi, u32 reg, u32 val)
+{
+       writel_relaxed(val, dsi->base + reg);
+}
+
+static inline u32 dsi_read(struct dw_mipi_dsi *dsi, u32 reg)
+{
+       return readl_relaxed(dsi->base + reg);
+}
+
+static inline void dsi_set(struct dw_mipi_dsi *dsi, u32 reg, u32 mask)
+{
+       dsi_write(dsi, reg, dsi_read(dsi, reg) | mask);
+}
+
+static inline void dsi_clear(struct dw_mipi_dsi *dsi, u32 reg, u32 mask)
+{
+       dsi_write(dsi, reg, dsi_read(dsi, reg) & ~mask);
+}
+
+static inline void dsi_update_bits(struct dw_mipi_dsi *dsi, u32 reg, u32 mask,
+                                  u32 val)
+{
+       dsi_write(dsi, reg, (dsi_read(dsi, reg) & ~mask) | val);
+}
+
+/*
+ * DSI HOST PHY
+ */
+
+/* todo remove me (used only once) */
+static enum dsi_color dsi_color_from_mipi(enum mipi_dsi_pixel_format fmt)
+{
+       switch (fmt) {
+       case MIPI_DSI_FMT_RGB888:
+               return DSI_RGB888;
+       case MIPI_DSI_FMT_RGB666:
+               return DSI_RGB666_CONF2;
+       case MIPI_DSI_FMT_RGB666_PACKED:
+               return DSI_RGB666_CONF1;
+       case MIPI_DSI_FMT_RGB565:
+               return DSI_RGB565_CONF1;
+       default:
+               DRM_DEBUG_DRIVER("MIPI color invalid, so we use rgb888\n");
+       }
+       return DSI_RGB888;
+}
+
+static int dsi_pll_get_clkout_khz(int clkin_khz, int idf, int ndiv, int odf)
+{
+       /* prevent from division by 0 */
+       if (idf * odf)
+               return DIV_ROUND_CLOSEST(clkin_khz * ndiv, idf * odf);
+       else
+               return 0;
+}
+
+static int dsi_pll_get_params(int clkin_khz, int clkout_khz,
+                             int *idf, int *ndiv, int *odf)
+{
+       int i, o, n, n_min, n_max;
+       int fvco_min, fvco_max, delta, best_delta; /* all in khz */
+
+       /* Early checks preventing division by 0 & odd results */
+       if ((clkin_khz <= 0) || (clkout_khz <= 0))
+               return 0;
+
+       fvco_min = LANE_MIN_KBPS * 2 * ODF_MAX;
+       fvco_max = LANE_MAX_KBPS * 2 * ODF_MIN;
+
+       best_delta = 1000000; /* big started value (1000000khz) */
+
+       for (i = IDF_MIN; i <= IDF_MAX; i++) {
+               /* Compute ndiv range according to Fvco */
+               n_min = ((fvco_min * i) / (2 * clkin_khz)) + 1;
+               n_max = (fvco_max * i) / (2 * clkin_khz);
+
+               /* No need to continue idf loop if we reach ndiv max */
+               if (n_min >= NDIV_MAX)
+                       break;
+
+               /* Clamp ndiv to valid values */
+               if (n_min < NDIV_MIN)
+                       n_min = NDIV_MIN;
+               if (n_max > NDIV_MAX)
+                       n_max = NDIV_MAX;
+
+               for (o = ODF_MIN; o <= ODF_MAX; o *= 2) {
+                       n = DIV_ROUND_CLOSEST(i * o * clkout_khz, clkin_khz);
+                       /* Check ndiv according to vco range */
+                       if ((n < n_min) || (n > n_max))
+                               continue;
+                       /* Check if new delta is better & saves parameters */
+                       delta = dsi_pll_get_clkout_khz(clkin_khz, i, n, o) -
+                               clkout_khz;
+                       if (delta < 0)
+                               delta = -delta;
+                       if (delta < best_delta) {
+                               *idf = i;
+                               *ndiv = n;
+                               *odf = o;
+                               best_delta = delta;
+                       }
+                       /* fast return in case of "perfect result" */
+                       if (!delta)
+                               return 1;
+               }
+       }
+
+       return 1;
+}
+
+static int dw_mipi_dsi_phy_init(struct dw_mipi_dsi *dsi)
+{
+       u32 val;
+       int ret;
+
+       /* Enable the regulator */
+       dsi_set(dsi, DSI_WRPCR, WRPCR_REGEN | WRPCR_BGREN);
+       ret = readl_poll_timeout(dsi->base + DSI_WISR, val, val & WISR_RRS,
+                                SLEEP_US, TIMEOUT_US);
+       if (ret)
+               DRM_DEBUG_DRIVER("!TIMEOUT! waiting REGU, let's continue\n");
+
+       /* Enable the DSI PLL & wait for its lock */
+       dsi_set(dsi, DSI_WRPCR, WRPCR_PLLEN);
+       ret = readl_poll_timeout(dsi->base + DSI_WISR, val, val & WISR_PLLLS,
+                                SLEEP_US, TIMEOUT_US);
+       if (ret)
+               DRM_DEBUG_DRIVER("!TIMEOUT! waiting PLL, let's continue\n");
+
+       /* Enable the DSI wrapper */
+       dsi_set(dsi, DSI_WCR, WCR_DSIEN);
+
+       return 0;
+}
+
+static int dw_mipi_dsi_get_lane_bps(struct dw_mipi_dsi *dsi,
+                                   struct drm_display_mode *mode)
+{
+       unsigned int idf, ndiv, odf, pll_in_khz, pll_out_khz;
+       u32 val;
+       int bpp;
+
+       pll_in_khz = (unsigned int)(clk_get_rate(dsi->pllref_clk) / 1000);
+
+       /* Compute requested pll out */
+       bpp = mipi_dsi_pixel_format_to_bpp(dsi->format);
+       pll_out_khz = mode->clock * bpp / dsi->lanes;
+       /* Add 20% to pll out to be higher than pixel bw (burst mode only) */
+       pll_out_khz = (pll_out_khz * 12) / 10;
+       if (pll_out_khz > LANE_MAX_KBPS) {
+               pll_out_khz = LANE_MAX_KBPS;
+               DRM_DEBUG_DRIVER("Warning max phy mbps is used\n");
+       } else if (pll_out_khz < LANE_MIN_KBPS) {
+               pll_out_khz = LANE_MIN_KBPS;
+               DRM_DEBUG_DRIVER("Warning min phy mbps is used\n");
+       }
+
+       /* Compute best pll parameters */
+       dsi_pll_get_params(pll_in_khz, pll_out_khz, &idf, &ndiv, &odf);
+
+       /* Get the adjusted pll out value */
+       pll_out_khz = dsi_pll_get_clkout_khz(pll_in_khz, idf, ndiv, odf);
+
+       clk_enable(dsi->pclk);
+
+       /* Set the PLL division factors */
+       dsi_update_bits(dsi, DSI_WRPCR, WRPCR_NDIV | WRPCR_IDF | WRPCR_ODF,
+                       (ndiv << 2) | (idf << 11) | ((ffs(odf) - 1) << 16));
+
+       /* Compute uix4 & set the bit period in high-speed mode */
+       val = 4000000 / pll_out_khz;
+       dsi_update_bits(dsi, DSI_WPCR0, WPCR0_UIX4, val);
+
+       /* Select video mode by resetting DSIM bit */
+       dsi_clear(dsi, DSI_WCFGR, WCFGR_DSIM);
+
+       /* Select the color coding for host & wrapper (same value) */
+       dsi_update_bits(dsi, DSI_WCFGR, WCFGR_COLMUX,
+                       dsi_color_from_mipi(dsi->format) << 1);
+
+       clk_disable(dsi->pclk);
+
+       dsi->lane_mbps = pll_out_khz / 1000;
+
+       return 0;
+}
+
+/*
+ * DSI HOST DIGITAL
+ */
+
+static int dw_mipi_dsi_host_attach(struct mipi_dsi_host *host,
+                                  struct mipi_dsi_device *device)
+{
+       struct dw_mipi_dsi *dsi = host_to_dsi(host);
+
+       if (device->lanes > dsi->pdata->max_data_lanes) {
+               dev_err(dsi->dev, "the number of data lanes(%u) is too many\n",
+                       device->lanes);
+               return -EINVAL;
+       }
+
+       dsi->lanes = device->lanes;
+       dsi->channel = device->channel;
+       dsi->format = device->format;
+       dsi->mode_flags = device->mode_flags;
+       dsi->panel = of_drm_find_panel(device->dev.of_node);
+       if (dsi->panel)
+               return drm_panel_attach(dsi->panel, &dsi->connector);
+
+       return -EINVAL;
+}
+
+static int dw_mipi_dsi_host_detach(struct mipi_dsi_host *host,
+                                  struct mipi_dsi_device *device)
+{
+       struct dw_mipi_dsi *dsi = host_to_dsi(host);
+
+       drm_panel_detach(dsi->panel);
+
+       return 0;
+}
+
+static void dw_mipi_message_config(struct dw_mipi_dsi *dsi,
+                                  const struct mipi_dsi_msg *msg)
+{
+       bool lpm = msg->flags & MIPI_DSI_MSG_USE_LPM;
+       u32 val = 0;
+
+       if (msg->flags & MIPI_DSI_MSG_REQ_ACK)
+               val |= EN_ACK_RQST;
+       if (lpm)
+               val |= CMD_MODE_ALL_LP;
+
+       dsi_write(dsi, DSI_LPCLK_CTRL, lpm ? 0 : PHY_TXREQUESTCLKHS);
+
+       /* todo debug force the PHY_TXREQUESTCLKHS, to be improved... */
+       dsi_write(dsi, DSI_LPCLK_CTRL, PHY_TXREQUESTCLKHS);
+
+       dsi_write(dsi, DSI_CMD_MODE_CFG, val);
+}
+
+static int dw_mipi_dsi_gen_pkt_hdr_write(struct dw_mipi_dsi *dsi, u32 hdr_val)
+{
+       int ret;
+       u32 val, mask;
+
+       ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
+                                val, !(val & GEN_CMD_FULL), 1000,
+                                CMD_PKT_STATUS_TIMEOUT_US);
+       if (ret < 0) {
+               dev_err(dsi->dev, "failed to get available command FIFO\n");
+               return ret;
+       }
+
+       dsi_write(dsi, DSI_GEN_HDR, hdr_val);
+
+       mask = GEN_CMD_EMPTY | GEN_PLD_W_EMPTY;
+       ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
+                                val, (val & mask) == mask,
+                                1000, CMD_PKT_STATUS_TIMEOUT_US);
+       if (ret < 0) {
+               dev_err(dsi->dev, "failed to write command FIFO\n");
+               return ret;
+       }
+
+       return 0;
+}
+
+static int dw_mipi_dsi_dcs_short_write(struct dw_mipi_dsi *dsi,
+                                      const struct mipi_dsi_msg *msg)
+{
+       const u8 *tx_buf = msg->tx_buf;
+       u16 data = 0;
+       u32 val;
+
+       if (msg->tx_len > 0)
+               data |= tx_buf[0];
+       if (msg->tx_len > 1)
+               data |= tx_buf[1] << 8;
+
+       if (msg->tx_len > 2) {
+               dev_err(dsi->dev, "too long tx buf length %zu for short 
write\n",
+                       msg->tx_len);
+               return -EINVAL;
+       }
+
+       val = GEN_HDATA(data) | GEN_HTYPE(msg->type);
+       return dw_mipi_dsi_gen_pkt_hdr_write(dsi, val);
+}
+
+static int dw_mipi_dsi_dcs_long_write(struct dw_mipi_dsi *dsi,
+                                     const struct mipi_dsi_msg *msg)
+{
+       const u8 *tx_buf = msg->tx_buf;
+       int len = msg->tx_len, pld_data_bytes = sizeof(u32), ret;
+       u32 hdr_val = GEN_HDATA(msg->tx_len) | GEN_HTYPE(msg->type);
+       u32 remainder;
+       u32 val;
+
+       if (msg->tx_len < 3) {
+               dev_err(dsi->dev, "wrong tx buf length %zu for long write\n",
+                       msg->tx_len);
+               return -EINVAL;
+       }
+
+       while (DIV_ROUND_UP(len, pld_data_bytes)) {
+               if (len < pld_data_bytes) {
+                       remainder = 0;
+                       memcpy(&remainder, tx_buf, len);
+                       dsi_write(dsi, DSI_GEN_PLD_DATA, remainder);
+                       len = 0;
+               } else {
+                       memcpy(&remainder, tx_buf, pld_data_bytes);
+                       dsi_write(dsi, DSI_GEN_PLD_DATA, remainder);
+                       tx_buf += pld_data_bytes;
+                       len -= pld_data_bytes;
+               }
+
+               ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
+                                        val, !(val & GEN_PLD_W_FULL), 1000,
+                                        CMD_PKT_STATUS_TIMEOUT_US);
+               if (ret < 0) {
+                       dev_err(dsi->dev,
+                               "failed to get available write payload FIFO\n");
+                       return ret;
+               }
+       }
+
+       return dw_mipi_dsi_gen_pkt_hdr_write(dsi, hdr_val);
+}
+
+static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host,
+                                        const struct mipi_dsi_msg *msg)
+{
+       struct dw_mipi_dsi *dsi = host_to_dsi(host);
+       int ret;
+
+       /*
+        * todo dw drv improvements
+        * use mipi_dsi_create_packet() instead of all following
+        * functions and code (no switch cases, no
+        * dw_mipi_dsi_dcs_short_write(), only the loop in long_write...)
+        * and use packet.header...
+        */
+       dw_mipi_message_config(dsi, msg);
+
+       switch (msg->type) {
+       case MIPI_DSI_DCS_SHORT_WRITE:
+       case MIPI_DSI_DCS_SHORT_WRITE_PARAM:
+       case MIPI_DSI_SET_MAXIMUM_RETURN_PACKET_SIZE:
+               ret = dw_mipi_dsi_dcs_short_write(dsi, msg);
+               break;
+       case MIPI_DSI_DCS_LONG_WRITE:
+               ret = dw_mipi_dsi_dcs_long_write(dsi, msg);
+               break;
+       default:
+               dev_err(dsi->dev, "unsupported message type 0x%02x\n",
+                       msg->type);
+               ret = -EINVAL;
+       }
+
+       return ret;
+}
+
+static const struct mipi_dsi_host_ops dw_mipi_dsi_host_ops = {
+       .attach = dw_mipi_dsi_host_attach,
+       .detach = dw_mipi_dsi_host_detach,
+       .transfer = dw_mipi_dsi_host_transfer,
+};
+
+static void dw_mipi_dsi_video_mode_config(struct dw_mipi_dsi *dsi)
+{
+       u32 val;
+
+       /*
+        * todo dw drv improvements
+        * enabling low power is panel-dependent, we should use the
+        * panel configuration here...
+        */
+       val = ENABLE_LOW_POWER;
+
+       if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST)
+               val |= VID_MODE_TYPE_BURST;
+       else if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
+               val |= VID_MODE_TYPE_NON_BURST_SYNC_PULSES;
+       else
+               val |= VID_MODE_TYPE_NON_BURST_SYNC_EVENTS;
+
+       dsi_write(dsi, DSI_VID_MODE_CFG, val);
+}
+
+static void dw_mipi_dsi_set_mode(struct dw_mipi_dsi *dsi,
+                                enum dw_mipi_dsi_mode mode)
+{
+       if (mode == DW_MIPI_DSI_CMD_MODE) {
+               dsi_write(dsi, DSI_PWR_UP, RESET);
+               dsi_write(dsi, DSI_MODE_CFG, ENABLE_CMD_MODE);
+               dsi_write(dsi, DSI_PWR_UP, POWERUP);
+       } else {
+               dsi_write(dsi, DSI_PWR_UP, RESET);
+               dsi_write(dsi, DSI_MODE_CFG, ENABLE_VIDEO_MODE);
+               dw_mipi_dsi_video_mode_config(dsi);
+               dsi_write(dsi, DSI_LPCLK_CTRL, PHY_TXREQUESTCLKHS);
+               dsi_write(dsi, DSI_PWR_UP, POWERUP);
+       }
+}
+
+static void dw_mipi_dsi_disable(struct dw_mipi_dsi *dsi)
+{
+       dsi_write(dsi, DSI_PWR_UP, RESET);
+       dsi_write(dsi, DSI_PHY_RSTZ, PHY_RSTZ);
+}
+
+static void dw_mipi_dsi_init(struct dw_mipi_dsi *dsi)
+{
+       /*
+        * The maximum permitted escape clock is 20MHz and it is derived from
+        * lanebyteclk, which is running at "lane_mbps / 8".  Thus we want:
+        *
+        *     (lane_mbps >> 3) / esc_clk_division < 20
+        * which is:
+        *     (lane_mbps >> 3) / 20 > esc_clk_division
+        */
+       u32 esc_clk_division = (dsi->lane_mbps >> 3) / 20 + 1;
+
+       dsi_write(dsi, DSI_PWR_UP, RESET);
+       dsi_write(dsi, DSI_PHY_RSTZ, PHY_DISFORCEPLL | PHY_DISABLECLK
+                 | PHY_RSTZ | PHY_SHUTDOWNZ);
+       /*
+        * todo dw drv improvements
+        * timeout clock division should be computed with the
+        * high speed transmission counter timeout and byte lane...
+        */
+       dsi_write(dsi, DSI_CLKMGR_CFG, TO_CLK_DIVIDSION(10) |
+                 TX_ESC_CLK_DIVIDSION(esc_clk_division));
+}
+
+static void dw_mipi_dsi_dpi_config(struct dw_mipi_dsi *dsi,
+                                  struct drm_display_mode *mode)
+{
+       u32 val = 0, color = 0;
+
+       switch (dsi->format) {
+       case MIPI_DSI_FMT_RGB888:
+               color = DPI_COLOR_CODING_24BIT;
+               break;
+       case MIPI_DSI_FMT_RGB666:
+               color = DPI_COLOR_CODING_18BIT_2 | EN18_LOOSELY;
+               break;
+       case MIPI_DSI_FMT_RGB666_PACKED:
+               color = DPI_COLOR_CODING_18BIT_1;
+               break;
+       case MIPI_DSI_FMT_RGB565:
+               color = DPI_COLOR_CODING_16BIT_1;
+               break;
+       }
+
+       if (mode->flags & DRM_MODE_FLAG_NVSYNC)
+               val |= VSYNC_ACTIVE_LOW;
+       if (mode->flags & DRM_MODE_FLAG_NHSYNC)
+               val |= HSYNC_ACTIVE_LOW;
+
+       dsi_write(dsi, DSI_DPI_VCID, DPI_VID(dsi->channel));
+       dsi_write(dsi, DSI_DPI_COLOR_CODING, color);
+       dsi_write(dsi, DSI_DPI_CFG_POL, val);
+       /*
+        * todo dw drv improvements
+        * largest packet sizes during hfp or during vsa/vpb/vfp
+        * should be computed according to byte lane, lane number and only
+        * if sending lp cmds in high speed is enable (PHY_TXREQUESTCLKHS)
+        */
+       dsi_write(dsi, DSI_DPI_LP_CMD_TIM, OUTVACT_LPCMD_TIME(4)
+                 | INVACT_LPCMD_TIME(4));
+}
+
+static void dw_mipi_dsi_packet_handler_config(struct dw_mipi_dsi *dsi)
+{
+       dsi_write(dsi, DSI_PCKHDL_CFG, EN_CRC_RX | EN_ECC_RX | EN_BTA);
+}
+
+static void dw_mipi_dsi_video_packet_config(struct dw_mipi_dsi *dsi,
+                                           struct drm_display_mode *mode)
+{
+       /*
+        * todo dw drv improvements
+        * only burst mode is supported here. For non-burst video modes,
+        * we should compute DSI_VID_PKT_SIZE, DSI_VCCR.NUMC &
+        * DSI_VNPCR.NPSIZE... especially because this driver supports
+        * non-burst video modes, see dw_mipi_dsi_video_mode_config()...
+        */
+       dsi_write(dsi, DSI_VID_PKT_SIZE, VID_PKT_SIZE(mode->hdisplay));
+}
+
+static void dw_mipi_dsi_command_mode_config(struct dw_mipi_dsi *dsi)
+{
+       /*
+        * todo dw drv improvements
+        * compute high speed transmission counter timeout according
+        * to the timeout clock division (TO_CLK_DIVIDSION) and byte lane...
+        */
+       dsi_write(dsi, DSI_TO_CNT_CFG, HSTX_TO_CNT(1000) | LPRX_TO_CNT(1000));
+       /*
+        * todo dw drv improvements
+        * the Bus-Turn-Around Timeout Counter should be computed
+        * according to byte lane...
+        */
+       dsi_write(dsi, DSI_BTA_TO_CNT, 0xd00);
+       dsi_write(dsi, DSI_MODE_CFG, ENABLE_CMD_MODE);
+}
+
+/* Get lane byte clock cycles. */
+static u32 dw_mipi_dsi_get_hcomponent_lbcc(struct dw_mipi_dsi *dsi,
+                                          struct drm_display_mode *mode,
+                                          u32 hcomponent)
+{
+       u32 frac, lbcc;
+
+       lbcc = hcomponent * dsi->lane_mbps * MSEC_PER_SEC / 8;
+
+       frac = lbcc % mode->clock;
+       lbcc = lbcc / mode->clock;
+       if (frac)
+               lbcc++;
+
+       return lbcc;
+}
+
+static void dw_mipi_dsi_line_timer_config(struct dw_mipi_dsi *dsi,
+                                         struct drm_display_mode *mode)
+{
+       u32 htotal, hsa, hbp, lbcc;
+
+       htotal = mode->htotal;
+       hsa = mode->hsync_end - mode->hsync_start;
+       hbp = mode->htotal - mode->hsync_end;
+
+       /*
+        * todo dw drv improvements
+        * computations below may be improved...
+        */
+       lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, htotal);
+       dsi_write(dsi, DSI_VID_HLINE_TIME, lbcc);
+
+       lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, hsa);
+       dsi_write(dsi, DSI_VID_HSA_TIME, lbcc);
+
+       lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, hbp);
+       dsi_write(dsi, DSI_VID_HBP_TIME, lbcc);
+}
+
+static void dw_mipi_dsi_vertical_timing_config(struct dw_mipi_dsi *dsi,
+                                              struct drm_display_mode *mode)
+{
+       u32 vactive, vsa, vfp, vbp;
+
+       vactive = mode->vdisplay;
+       vsa = mode->vsync_end - mode->vsync_start;
+       vfp = mode->vsync_start - mode->vdisplay;
+       vbp = mode->vtotal - mode->vsync_end;
+
+       dsi_write(dsi, DSI_VID_VACTIVE_LINES, vactive);
+       dsi_write(dsi, DSI_VID_VSA_LINES, vsa);
+       dsi_write(dsi, DSI_VID_VFP_LINES, vfp);
+       dsi_write(dsi, DSI_VID_VBP_LINES, vbp);
+}
+
+static void dw_mipi_dsi_dphy_timing_config(struct dw_mipi_dsi *dsi)
+{
+       /*
+        * todo dw drv improvements
+        * data & clock lane timers should be computed according to panel
+        * blankings and to the automatic clock lane control mode...
+        * note: DSI_PHY_TMR_CFG.MAX_RD_TIME should be in line with
+        * DSI_CMD_MODE_CFG.MAX_RD_PKT_SIZE_LP (see CMD_MODE_ALL_LP)
+        */
+       dsi_write(dsi, DSI_PHY_TMR_CFG, PHY_HS2LP_TIME(0x40)
+                 | PHY_LP2HS_TIME(0x40) | MAX_RD_TIME(10000));
+
+       dsi_write(dsi, DSI_PHY_TMR_LPCLK_CFG, PHY_CLKHS2LP_TIME(0x40)
+                 | PHY_CLKLP2HS_TIME(0x40));
+}
+
+static void dw_mipi_dsi_dphy_interface_config(struct dw_mipi_dsi *dsi)
+{
+       /*
+        * todo dw drv improvements
+        * stop wait time should be the maximum between host dsi
+        * and panel stop wait times
+        */
+       dsi_write(dsi, DSI_PHY_IF_CFG, PHY_STOP_WAIT_TIME(0x20) |
+                 N_LANES(dsi->lanes));
+}
+
+static void dw_mipi_dsi_clear_err(struct dw_mipi_dsi *dsi)
+{
+       dsi_read(dsi, DSI_INT_ST0);
+       dsi_read(dsi, DSI_INT_ST1);
+       dsi_write(dsi, DSI_INT_MSK0, 0);
+       dsi_write(dsi, DSI_INT_MSK1, 0);
+}
+
+static void dw_mipi_dsi_bridge_disable(struct drm_bridge *bridge)
+{
+       struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
+
+       if (dsi->dpms_mode != DRM_MODE_DPMS_ON)
+               return;
+
+       if (clk_enable(dsi->pclk)) {
+               dev_err(dsi->dev, "%s: Failed to enable pclk\n", __func__);
+               return;
+       }
+
+       drm_panel_disable(dsi->panel);
+
+       dw_mipi_dsi_set_mode(dsi, DW_MIPI_DSI_CMD_MODE);
+       drm_panel_unprepare(dsi->panel);
+
+       dw_mipi_dsi_disable(dsi);
+       pm_runtime_put(dsi->dev);
+       clk_disable(dsi->pclk);
+       dsi->dpms_mode = DRM_MODE_DPMS_OFF;
+}
+
+static void dw_mipi_dsi_bridge_enable(struct drm_bridge *bridge)
+{
+       struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
+       struct drm_encoder *encoder = bridge->encoder;
+       struct drm_display_mode *mode = &encoder->crtc->state->adjusted_mode;
+       int ret;
+
+       ret = dw_mipi_dsi_get_lane_bps(dsi, mode);
+       if (ret < 0)
+               return;
+
+       if (dsi->dpms_mode == DRM_MODE_DPMS_ON)
+               return;
+
+       if (clk_enable(dsi->pclk)) {
+               dev_err(dsi->dev, "%s: Failed to enable pclk\n", __func__);
+               return;
+       }
+
+       pm_runtime_get_sync(dsi->dev);
+       dw_mipi_dsi_init(dsi);
+       dw_mipi_dsi_dpi_config(dsi, mode);
+       dw_mipi_dsi_packet_handler_config(dsi);
+       dw_mipi_dsi_video_mode_config(dsi);
+       dw_mipi_dsi_video_packet_config(dsi, mode);
+       dw_mipi_dsi_command_mode_config(dsi);
+       dw_mipi_dsi_line_timer_config(dsi, mode);
+       dw_mipi_dsi_vertical_timing_config(dsi, mode);
+       dw_mipi_dsi_dphy_timing_config(dsi);
+       dw_mipi_dsi_dphy_interface_config(dsi);
+       dw_mipi_dsi_clear_err(dsi);
+
+       /*
+        * todo dw drv improvements
+        * following command is inside dw_mipi_dsi_phy_init()
+        * but this function is also required here. We way move it in the
+        * phy but here we are using dsi regs...
+        * maybe add the waiting loop here too...
+        */
+       dsi_write(dsi, DSI_PHY_RSTZ, PHY_ENFORCEPLL | PHY_ENABLECLK |
+                                    PHY_UNRSTZ | PHY_UNSHUTDOWNZ);
+
+       dw_mipi_dsi_phy_init(dsi);
+       dw_mipi_dsi_wait_for_two_frames(mode);
+
+       dw_mipi_dsi_set_mode(dsi, DW_MIPI_DSI_CMD_MODE);
+       if (drm_panel_prepare(dsi->panel))
+               dev_err(dsi->dev, "failed to prepare panel\n");
+
+       dw_mipi_dsi_set_mode(dsi, DW_MIPI_DSI_VID_MODE);
+       drm_panel_enable(dsi->panel);
+
+       clk_disable(dsi->pclk);
+
+       dsi->dpms_mode = DRM_MODE_DPMS_ON;
+}
+
+static int dw_mipi_dsi_connector_get_modes(struct drm_connector *connector)
+{
+       struct dw_mipi_dsi *dsi = con_to_dsi(connector);
+
+       return drm_panel_get_modes(dsi->panel);
+}
+
+static struct drm_connector_helper_funcs dw_mipi_dsi_connector_helper_funcs = {
+       .get_modes = dw_mipi_dsi_connector_get_modes,
+};
+
+static void dw_mipi_dsi_drm_connector_destroy(struct drm_connector *connector)
+{
+       drm_connector_unregister(connector);
+       drm_connector_cleanup(connector);
+}
+
+static const struct drm_connector_funcs dw_mipi_dsi_atomic_connector_funcs = {
+       .dpms = drm_atomic_helper_connector_dpms,
+       .fill_modes = drm_helper_probe_single_connector_modes,
+       .destroy = dw_mipi_dsi_drm_connector_destroy,
+       .reset = drm_atomic_helper_connector_reset,
+       .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
+       .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
+};
+
+static int dw_mipi_dsi_bridge_attach(struct drm_bridge *bridge)
+{
+       struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
+       struct drm_connector *connector = &dsi->connector;
+
+       if (!bridge->encoder) {
+               DRM_ERROR("Parent encoder object not found");
+               return -ENODEV;
+       }
+
+       /* Set the encoder type as caller does not know it */
+       bridge->encoder->encoder_type = DRM_MODE_ENCODER_DSI;
+
+       connector->polled = DRM_CONNECTOR_POLL_HPD;
+
+       drm_connector_helper_add(connector,
+                                &dw_mipi_dsi_connector_helper_funcs);
+
+       drm_connector_init(bridge->dev, connector,
+                          &dw_mipi_dsi_atomic_connector_funcs,
+                          DRM_MODE_CONNECTOR_DSI);
+
+       drm_mode_connector_attach_encoder(connector, bridge->encoder);
+
+       return 0;
+}
+
+static struct drm_bridge_funcs dw_mipi_dsi_bridge_funcs = {
+       .enable = dw_mipi_dsi_bridge_enable,
+       .disable = dw_mipi_dsi_bridge_disable,
+       .attach = dw_mipi_dsi_bridge_attach,
+};
+
+static struct dw_mipi_dsi_plat_data stm_mipi_dsi_drv_data = {
+       .max_data_lanes = 2,
+};
+
+static const struct of_device_id dw_mipi_dsi_dt_ids[] = {
+       {
+        .compatible = "st,stm32-dsi_host",
+        .data = &stm_mipi_dsi_drv_data,
+       },
+       { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, dw_mipi_dsi_dt_ids);
+
+static int dw_mipi_dsi_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       const struct of_device_id *of_id =
+                       of_match_device(dw_mipi_dsi_dt_ids, dev);
+       const struct dw_mipi_dsi_plat_data *pdata = of_id->data;
+       struct reset_control *apb_rst;
+       struct dw_mipi_dsi *dsi;
+       struct resource *res;
+       int ret;
+
+       dsi = devm_kzalloc(dev, sizeof(*dsi), GFP_KERNEL);
+       if (!dsi)
+               return -ENOMEM;
+
+       dsi->dev = dev;
+       dsi->pdata = pdata;
+       dsi->dpms_mode = DRM_MODE_DPMS_OFF;
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       if (!res)
+               return -ENODEV;
+
+       dsi->base = devm_ioremap_resource(dev, res);
+       if (IS_ERR(dsi->base))
+               return PTR_ERR(dsi->base);
+
+       dsi->pllref_clk = devm_clk_get(dev, "ref");
+       if (IS_ERR(dsi->pllref_clk)) {
+               ret = PTR_ERR(dsi->pllref_clk);
+               dev_err(dev, "Unable to get pll reference clock: %d\n", ret);
+               return ret;
+       }
+
+       dsi->pclk = devm_clk_get(dev, "pclk");
+       if (IS_ERR(dsi->pclk)) {
+               ret = PTR_ERR(dsi->pclk);
+               dev_err(dev, "Unable to get pclk: %d\n", ret);
+               return ret;
+       }
+
+       /*
+        * Note that the reset was not defined in the initial device tree, so
+        * we have to be prepared for it not being found.
+        */
+       apb_rst = devm_reset_control_get(dev, "apb");
+       if (IS_ERR(apb_rst)) {
+               ret = PTR_ERR(apb_rst);
+               if (ret == -ENOENT) {
+                       apb_rst = NULL;
+               } else {
+                       dev_err(dev, "Unable to get reset control: %d\n", ret);
+                       return ret;
+               }
+       }
+
+       if (apb_rst) {
+               ret = clk_prepare_enable(dsi->pclk);
+               if (ret) {
+                       dev_err(dev, "%s: Failed to enable pclk\n", __func__);
+                       return ret;
+               }
+
+               reset_control_assert(apb_rst);
+               usleep_range(10, 20);
+               reset_control_deassert(apb_rst);
+
+               clk_disable(dsi->pclk);
+       }
+
+       ret = clk_prepare_enable(dsi->pllref_clk);
+       if (ret) {
+               dev_err(dev, "%s: Failed to enable pllref_clk\n", __func__);
+               return ret;
+       }
+
+       pm_runtime_enable(dev);
+
+       dsi->dsi_host.ops = &dw_mipi_dsi_host_ops;
+       dsi->dsi_host.dev = dev;
+       ret = mipi_dsi_host_register(&dsi->dsi_host);
+       if (ret) {
+               dev_err(dev, "Failed to register MIPI host: %d\n", ret);
+               goto err_cleanup;
+       }
+
+       dsi->bridge.driver_private = dsi;
+       dsi->bridge.funcs = &dw_mipi_dsi_bridge_funcs;
+#ifdef CONFIG_OF
+       dsi->bridge.of_node = pdev->dev.of_node;
+#endif
+       ret = drm_bridge_add(&dsi->bridge);
+       if (ret) {
+               dev_err(dev, "Failed to add bridge: %d\n", ret);
+               goto err_mipi_dsi_host;
+       }
+
+       clk_enable(dsi->pclk);
+
+       dev_set_drvdata(dev, dsi);
+       return 0;
+
+err_mipi_dsi_host:
+       mipi_dsi_host_unregister(&dsi->dsi_host);
+err_cleanup:
+       clk_disable_unprepare(dsi->pllref_clk);
+       return ret;
+}
+
+static int dw_mipi_dsi_remove(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct dw_mipi_dsi *dsi = dev_get_drvdata(dev);
+
+       drm_bridge_remove(&dsi->bridge);
+       mipi_dsi_host_unregister(&dsi->dsi_host);
+       pm_runtime_disable(dev);
+       clk_disable_unprepare(dsi->pllref_clk);
+
+       return 0;
+}
+
+static struct platform_driver dw_mipi_dsi_driver = {
+       .probe          = dw_mipi_dsi_probe,
+       .remove         = dw_mipi_dsi_remove,
+       .driver         = {
+               .of_match_table = dw_mipi_dsi_dt_ids,
+               .name   = DRIVER_NAME,
+       },
+};
+
+module_platform_driver(dw_mipi_dsi_driver);
+
+MODULE_DESCRIPTION("ROCKCHIP MIPI DSI host controller driver");
+MODULE_AUTHOR("Chris Zhong <z...@rock-chips.com>");
+MODULE_AUTHOR("Philippe Cornu <philippe.co...@st.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRIVER_NAME);
-- 
1.9.1

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