The Low-Voltage Differential Signaling (LVDS) Display Interface
Transmitter handles the LVDS protocol: it maps the pixels received from
the upstream Pixel-DMA LCD-TFT Display Controller (LTDC) onto the LVDS
PHY.
It regroups three sub blocks:
* LVDS host: handles the LVDS protocol (FPD / OpenLDI) and maps
its input pixels onto the data lanes of the PHY
* LVDS PHY: parallelize the data and drives the LVDS data lanes
* LVDS wrapper: handles top-level settings
The LVDS controller driver supports the following high-level features:
* FDP-Link-I and OpenLDI (v0.95) protocols
* Single-Link or Dual-Link operation
* Single-Display or Double-Display (with the same content
duplicated on both)
* Flexible Bit-Mapping, including JEIDA and VESA
* RGB888 or RGB666 output
* Synchronous design, with one input pixel per clock cycle
Signed-off-by: Raphael Gallais-Pou <raphael.gallais-pou@xxxxxxxxxxx>
---
drivers/gpu/drm/stm/Kconfig | 11 +
drivers/gpu/drm/stm/Makefile | 2 +
drivers/gpu/drm/stm/lvds.c | 1226 ++++++++++++++++++++++++++++++++++
3 files changed, 1239 insertions(+)
create mode 100644 drivers/gpu/drm/stm/lvds.c
diff --git a/drivers/gpu/drm/stm/Kconfig b/drivers/gpu/drm/stm/Kconfig
index fa49cde43bb2..9627814d027c 100644
--- a/drivers/gpu/drm/stm/Kconfig
+++ b/drivers/gpu/drm/stm/Kconfig
@@ -20,3 +20,14 @@ config DRM_STM_DSI
select DRM_DW_MIPI_DSI
help
Choose this option for MIPI DSI support on STMicroelectronics SoC.
+
+config DRM_STM_LVDS
+ tristate "STMicroelectronics LVDS Display Interface Transmitter DRM driver"
+ depends on DRM_STM
+ help
+ Enable support for LVDS encoders on STMicroelectronics SoC.
+ The STM LVDS is a bridge which serialize pixel stream onto
+ a LVDS protocol.
+
+ To compile this driver as a module, choose M here: the module will be
+ called lvds.
diff --git a/drivers/gpu/drm/stm/Makefile b/drivers/gpu/drm/stm/Makefile
index 4df5caf01f35..ad740d6175a6 100644
--- a/drivers/gpu/drm/stm/Makefile
+++ b/drivers/gpu/drm/stm/Makefile
@@ -5,4 +5,6 @@ stm-drm-y := \
obj-$(CONFIG_DRM_STM_DSI) += dw_mipi_dsi-stm.o
+obj-$(CONFIG_DRM_STM_LVDS) += lvds.o
+
obj-$(CONFIG_DRM_STM) += stm-drm.o
diff --git a/drivers/gpu/drm/stm/lvds.c b/drivers/gpu/drm/stm/lvds.c
new file mode 100644
index 000000000000..f01490939ab5
--- /dev/null
+++ b/drivers/gpu/drm/stm/lvds.c
@@ -0,0 +1,1226 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2023, STMicroelectronics - All Rights Reserved
+ * Author(s): Raphaël GALLAIS-POU <raphael.gallais-pou@xxxxxxxxxxx> for STMicroelectronics.
+ */
+
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_bridge.h>
+#include <drm/drm_device.h>
+#include <drm/drm_of.h>
+#include <drm/drm_panel.h>
+#include <drm/drm_print.h>
+#include <drm/drm_probe_helper.h>
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/media-bus-format.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/reset.h>
+
+/* LVDS Host registers */
+#define LVDS_CR 0x0000 /* configuration register */
+#define LVDS_DMLCR0 0x0004 /* data mapping lsb configuration register 0 */
+#define LVDS_DMMCR0 0x0008 /* data mapping msb configuration register 0 */
+#define LVDS_DMLCR1 0x000C /* data mapping lsb configuration register 1 */
+#define LVDS_DMMCR1 0x0010 /* data mapping msb configuration register 1 */
+#define LVDS_DMLCR2 0x0014 /* data mapping lsb configuration register 2 */
+#define LVDS_DMMCR2 0x0018 /* data mapping msb configuration register 2 */
+#define LVDS_DMLCR3 0x001C /* data mapping lsb configuration register 3 */
+#define LVDS_DMMCR3 0x0020 /* data mapping msb configuration register 3 */
+#define LVDS_DMLCR4 0x0024 /* data mapping lsb configuration register 4 */
+#define LVDS_DMMCR4 0x0028 /* data mapping msb configuration register 4 */
+#define LVDS_CDL1CR 0x002C /* channel distrib link 1 configuration register */
+#define LVDS_CDL2CR 0x0030 /* channel distrib link 2 configuration register */
+
+#define CDL1CR_DEFAULT 0x04321 /* Default value for CDL1CR */
+#define CDL2CR_DEFAULT 0x59876 /* Default value for CDL2CR */
+
+#define LVDS_DMLCR(bit) (LVDS_DMLCR0 + 0x8 * (bit))
+#define LVDS_DMMCR(bit) (LVDS_DMMCR0 + 0x8 * (bit))
+
+/* LVDS Wrapper registers */
+#define LVDS_WCLKCR 0x11B0 /* Wrapper clock control register */
+
+#define LVDS_HWCFGR 0x1FF0 /* HW configuration register */
+#define LVDS_VERR 0x1FF4 /* Version register */
+#define LVDS_IPIDR 0x1FF8 /* Identification register */
+#define LVDS_SIDR 0x1FFC /* Size Identification register */
+
+/* Bitfield description */
+#define CR_LVDSEN BIT(0) /* LVDS PHY Enable */
+#define CR_HSPOL BIT(1) /* Horizontal Synchronization Polarity */
+#define CR_VSPOL BIT(2) /* Vertical Synchronization Polarity */
+#define CR_DEPOL BIT(3) /* Data Enable Polarity */
+#define CR_CI BIT(4) /* Control Internal (software controlled bit) */
+#define CR_LKMOD BIT(5) /* Link Mode, for both Links */
+#define CR_LKPHA BIT(6) /* Link Phase, for both Links */
+#define CR_LK1POL GENMASK(20, 16) /* Link-1 output Polarity */
+#define CR_LK2POL GENMASK(25, 21) /* Link-2 output Polarity */
+
+#define DMMCRx_MAP0 GENMASK(4, 0) /* Mapping for bit 0 of datalane x */
+#define DMMCRx_MAP1 GENMASK(9, 5) /* Mapping for bit 1 of datalane x */
+#define DMMCRx_MAP2 GENMASK(14, 10) /* Mapping for bit 2 of datalane x */
+#define DMMCRx_MAP3 GENMASK(19, 15) /* Mapping for bit 3 of datalane x */
+#define DMLCRx_MAP4 GENMASK(4, 0) /* Mapping for bit 4 of datalane x */
+#define DMLCRx_MAP5 GENMASK(9, 5) /* Mapping for bit 5 of datalane x */
+#define DMLCRx_MAP6 GENMASK(14, 10) /* Mapping for bit 6 of datalane x */
+
+#define CDLCRx_DISTR0 GENMASK(3, 0) /* Channel distribution for lane 0 */
+#define CDLCRx_DISTR1 GENMASK(7, 4) /* Channel distribution for lane 1 */
+#define CDLCRx_DISTR2 GENMASK(11, 8) /* Channel distribution for lane 2 */
+#define CDLCRx_DISTR3 GENMASK(15, 12) /* Channel distribution for lane 3 */
+#define CDLCRx_DISTR4 GENMASK(19, 16) /* Channel distribution for lane 4 */
+
+#define PHY_GCR_BIT_CLK_OUT BIT(0) /* BIT clock enable */
+#define PHY_GCR_LS_CLK_OUT BIT(4) /* LS clock enable */
+#define PHY_GCR_DP_CLK_OUT BIT(8) /* DP clock enable */
+#define PHY_GCR_RSTZ BIT(24) /* LVDS PHY digital reset */
+#define PHY_GCR_DIV_RSTN BIT(25) /* Output divider reset */
+#define PHY_SCR_TX_EN BIT(16) /* Transmission mode enable */
+/* Current mode driver enable */
+#define PHY_CMCR_CM_EN_DL (BIT(28) | BIT(20) | BIT(12) | BIT(4))
+#define PHY_CMCR_CM_EN_DL4 BIT(4)
+/* Bias enable */
+#define PHY_BCR1_EN_BIAS_DL (BIT(16) | BIT(12) | BIT(8) | BIT(4) | BIT(0))
+#define PHY_BCR2_BIAS_EN BIT(28)
+/* Voltage mode driver enable */
+#define PHY_BCR3_VM_EN_DL (BIT(16) | BIT(12) | BIT(8) | BIT(4) | BIT(0))
+#define PHY_DCR_POWER_OK BIT(12)
+#define PHY_CFGCR_EN_DIG_DL GENMASK(4, 0) /* LVDS PHY digital lane enable */
+#define PHY_PLLCR1_PLL_EN BIT(0) /* LVDS PHY PLL enable */
+#define PHY_PLLCR1_EN_SD BIT(1) /* LVDS PHY PLL sigma-delta signal enable */
+#define PHY_PLLCR1_EN_TWG BIT(2) /* LVDS PHY PLL triangular wave generator enable */
+#define PHY_PLLCR1_DIV_EN BIT(8) /* LVDS PHY PLL dividers enable */
+#define PHY_PLLCR2_NDIV GENMASK(25, 16) /* NDIV mask value */
+#define PHY_PLLCR2_BDIV GENMASK(9, 0) /* BDIV mask value */
+#define PHY_PLLSR_PLL_LOCK BIT(0) /* LVDS PHY PLL lock status */
+#define PHY_PLLSDCR1_MDIV GENMASK(9, 0) /* MDIV mask value */
+#define PHY_PLLTESTCR_TDIV GENMASK(25, 16) /* TDIV mask value */
+#define PHY_PLLTESTCR_CLK_EN BIT(0) /* Test clock enable */
+#define PHY_PLLTESTCR_EN BIT(8) /* Test divider output enable */
+
+#define WCLKCR_SECND_CLKPIX_SEL BIT(0) /* Pixel clock selection */
+#define WCLKCR_SRCSEL BIT(8) /* Source selection for the pixel clock */
+
+/* Sleep & timeout for pll lock/unlock */
+#define SLEEP_US 1000
+#define TIMEOUT_US 200000
+
+/*
+ * The link phase defines whether an ODD pixel is carried over together with
+ * the next EVEN pixel or together with the previous EVEN pixel.
+ *
+ * LVDS_DUAL_LINK_EVEN_ODD_PIXELS (LKPHA = 0)
+ *
+ * ,--------. ,--------. ,--------. ,--------. ,---------.
+ * | ODD LK \/ PIXEL 3 \/ PIXEL 1 \/ PIXEL' 1 \/ PIXEL' 3 |
+ * | EVEN LK /\ PIXEL 2 /\ PIXEL' 0 /\ PIXEL' 2 /\ PIXEL' 4 |
+ * `--------' `--------' `--------' `--------' `---------'
+ *
+ * LVDS_DUAL_LINK_ODD_EVEN_PIXELS (LKPHA = 1)
+ *
+ * ,--------. ,--------. ,--------. ,--------. ,---------.
+ * | ODD LK \/ PIXEL 3 \/ PIXEL 1 \/ PIXEL' 1 \/ PIXEL' 3 |
+ * | EVEN LK /\ PIXEL 4 /\ PIXEL 2 /\ PIXEL' 0 /\ PIXEL' 2 |
+ * `--------' `--------' `--------' `--------' `---------'
+ *
+ */
+enum lvds_link_type {
+ LVDS_SINGLE_LINK_PRIMARY = 0,
+ LVDS_SINGLE_LINK_SECONDARY,
+ LVDS_DUAL_LINK_EVEN_ODD_PIXELS,
+ LVDS_DUAL_LINK_ODD_EVEN_PIXELS,
+};
+
+enum lvds_pixel {
+ PIX_R_0 = 0,
+ PIX_R_1,
+ PIX_R_2,
+ PIX_R_3,
+ PIX_R_4,
+ PIX_R_5,
+ PIX_R_6,
+ PIX_R_7,
+ PIX_G_0,
+ PIX_G_1,
+ PIX_G_2,
+ PIX_G_3,
+ PIX_G_4,
+ PIX_G_5,
+ PIX_G_6,
+ PIX_G_7,
+ PIX_B_0,
+ PIX_B_1,
+ PIX_B_2,
+ PIX_B_3,
+ PIX_B_4,
+ PIX_B_5,
+ PIX_B_6,
+ PIX_B_7,
+ PIX_H_S,
+ PIX_V_S,
+ PIX_D_E,
+ PIX_C_E,
+ PIX_C_I,
+ PIX_TOG,
+ PIX_ONE,
+ PIX_ZER,
+};
+
+struct phy_reg_offsets {
+ u32 GCR; /* Global Control Register */
+ u32 CMCR1; /* Current Mode Control Register 1 */
+ u32 CMCR2; /* Current Mode Control Register 2 */
+ u32 SCR; /* Serial Control Register */
+ u32 BCR1; /* Bias Control Register 1 */
+ u32 BCR2; /* Bias Control Register 2 */
+ u32 BCR3; /* Bias Control Register 3 */
+ u32 MPLCR; /* Monitor PLL Lock Control Register */
+ u32 DCR; /* Debug Control Register */
+ u32 SSR1; /* Spare Status Register 1 */
+ u32 CFGCR; /* Configuration Control Register */
+ u32 PLLCR1; /* PLL_MODE 1 Control Register */
+ u32 PLLCR2; /* PLL_MODE 2 Control Register */
+ u32 PLLSR; /* PLL Status Register */
+ u32 PLLSDCR1; /* PLL_SD_1 Control Register */
+ u32 PLLSDCR2; /* PLL_SD_2 Control Register */
+ u32 PLLTWGCR1;/* PLL_TWG_1 Control Register */
+ u32 PLLTWGCR2;/* PLL_TWG_2 Control Register */
+ u32 PLLCPCR; /* PLL_CP Control Register */
+ u32 PLLTESTCR;/* PLL_TEST Control Register */
+};
+
+struct lvds_phy_info {
+ u32 base;
+ struct phy_reg_offsets ofs;
+};
+
+static struct lvds_phy_info lvds_phy_16ff_primary = {
+ .base = 0x1000,
+ .ofs = {
+ .GCR = 0x0,
+ .CMCR1 = 0xC,
+ .CMCR2 = 0x10,
+ .SCR = 0x20,
+ .BCR1 = 0x2C,
+ .BCR2 = 0x30,
+ .BCR3 = 0x34,
+ .MPLCR = 0x64,
+ .DCR = 0x84,
+ .SSR1 = 0x88,
+ .CFGCR = 0xA0,
+ .PLLCR1 = 0xC0,
+ .PLLCR2 = 0xC4,
+ .PLLSR = 0xC8,
+ .PLLSDCR1 = 0xCC,
+ .PLLSDCR2 = 0xD0,
+ .PLLTWGCR1 = 0xD4,
+ .PLLTWGCR2 = 0xD8,
+ .PLLCPCR = 0xE0,
+ .PLLTESTCR = 0xE8,
+ }
+};
+
+static struct lvds_phy_info lvds_phy_16ff_secondary = {
+ .base = 0x1100,
+ .ofs = {
+ .GCR = 0x0,
+ .CMCR1 = 0xC,
+ .CMCR2 = 0x10,
+ .SCR = 0x20,
+ .BCR1 = 0x2C,
+ .BCR2 = 0x30,
+ .BCR3 = 0x34,
+ .MPLCR = 0x64,
+ .DCR = 0x84,
+ .SSR1 = 0x88,
+ .CFGCR = 0xA0,
+ .PLLCR1 = 0xC0,
+ .PLLCR2 = 0xC4,
+ .PLLSR = 0xC8,
+ .PLLSDCR1 = 0xCC,
+ .PLLSDCR2 = 0xD0,
+ .PLLTWGCR1 = 0xD4,
+ .PLLTWGCR2 = 0xD8,
+ .PLLCPCR = 0xE0,
+ .PLLTESTCR = 0xE8,
+ }
+};
+
+struct stm_lvds {
+ void __iomem *base;
+ struct device *dev;
+ struct clk *pclk; /* APB peripheral clock */
+ struct clk *pllref_clk; /* Reference clock for the internal PLL */
+ struct clk_hw lvds_ck_px; /* Pixel clock */
+ u32 pixel_clock_rate; /* Pixel clock rate */
+
+ struct lvds_phy_info *primary;
+ struct lvds_phy_info *secondary;
+
+ struct drm_bridge lvds_bridge;
+ struct drm_bridge *next_bridge;
+ struct drm_connector connector;
+ struct drm_encoder *encoder;
+ struct drm_panel *panel;
+
+ u32 hw_version;
+ u32 link_type;
+};
+
+#define bridge_to_stm_lvds(b) \
+ container_of(b, struct stm_lvds, lvds_bridge)
+
+#define connector_to_stm_lvds(c) \
+ container_of(c, struct stm_lvds, connector)
+
+#define lvds_is_dual_link(lvds) \
+ ({ \
+ typeof(lvds) __lvds = (lvds); \
+ __lvds == LVDS_DUAL_LINK_EVEN_ODD_PIXELS || \
+ __lvds == LVDS_DUAL_LINK_ODD_EVEN_PIXELS; \
+ })
+
+static inline void lvds_write(struct stm_lvds *lvds, u32 reg, u32 val)
+{
+ writel(val, lvds->base + reg);
+}
+
+static inline u32 lvds_read(struct stm_lvds *lvds, u32 reg)
+{
+ return readl(lvds->base + reg);
+}
+
+static inline void lvds_set(struct stm_lvds *lvds, u32 reg, u32 mask)
+{
+ lvds_write(lvds, reg, lvds_read(lvds, reg) | mask);
+}
+
+static inline void lvds_clear(struct stm_lvds *lvds, u32 reg, u32 mask)
+{
+ lvds_write(lvds, reg, lvds_read(lvds, reg) & ~mask);
+}
+
+/*
+ * Expected JEIDA-RGB888 data to be sent in LSB format
+ * bit6 ............................bit0
+ * CHAN0 {ONE, ONE, ZERO, ZERO, ZERO, ONE, ONE}
+ * CHAN1 {G2, R7, R6, R5, R4, R3, R2}
+ * CHAN2 {B3, B2, G7, G6, G5, G4, G3}
+ * CHAN3 {DE, VS, HS, B7, B6, B5, B4}
+ * CHAN4 {CE, B1, B0, G1, G0, R1, R0}
+ */
+enum lvds_pixel lvds_bitmap_jeida_rgb888[5][7] = {
+ { PIX_ONE, PIX_ONE, PIX_ZER, PIX_ZER, PIX_ZER, PIX_ONE, PIX_ONE },
+ { PIX_G_2, PIX_R_7, PIX_R_6, PIX_R_5, PIX_R_4, PIX_R_3, PIX_R_2 },
+ { PIX_B_3, PIX_B_2, PIX_G_7, PIX_G_6, PIX_G_5, PIX_G_4, PIX_G_3 },
+ { PIX_D_E, PIX_V_S, PIX_H_S, PIX_B_7, PIX_B_6, PIX_B_5, PIX_B_4 },
+ { PIX_C_E, PIX_B_1, PIX_B_0, PIX_G_1, PIX_G_0, PIX_R_1, PIX_R_0 }
+};
+
+/*
+ * Expected VESA-RGB888 data to be sent in LSB format
+ * bit6 ............................bit0
+ * CHAN0 {ONE, ONE, ZERO, ZERO, ZERO, ONE, ONE}
+ * CHAN1 {G0, R5, R4, R3, R2, R1, R0}
+ * CHAN2 {B1, B0, G5, G4, G3, G2, G1}
+ * CHAN3 {DE, VS, HS, B5, B4, B3, B2}
+ * CHAN4 {CE, B7, B6, G7, G6, R7, R6}
+ */
+enum lvds_pixel lvds_bitmap_vesa_rgb888[5][7] = {
+ { PIX_ONE, PIX_ONE, PIX_ZER, PIX_ZER, PIX_ZER, PIX_ONE, PIX_ONE },
+ { PIX_G_0, PIX_R_5, PIX_R_4, PIX_R_3, PIX_R_2, PIX_R_1, PIX_R_0 },
+ { PIX_B_1, PIX_B_0, PIX_G_5, PIX_G_4, PIX_G_3, PIX_G_2, PIX_G_1 },
+ { PIX_D_E, PIX_V_S, PIX_H_S, PIX_B_5, PIX_B_4, PIX_B_3, PIX_B_2 },
+ { PIX_C_E, PIX_B_7, PIX_B_6, PIX_G_7, PIX_G_6, PIX_R_7, PIX_R_6 }
+};
+
+/*
+ * Clocks and PHY related functions
+ */
+static int lvds_pll_enable(struct stm_lvds *lvds, struct lvds_phy_info *phy)
+{
+ struct drm_device *drm = lvds->lvds_bridge.dev;
+ u32 lvds_gcr;
+ int val, ret;
+
+ /*
+ * PLL lock timing control for the monitor unmask after startup (pll_en)
+ * Adjusted value so that the masking window is opened at start-up
+ */
+ lvds_write(lvds, phy->base + phy->ofs.MPLCR, (0x200 - 0x160) << 16);
+
+ /* Enable bias */
+ lvds_write(lvds, phy->base + phy->ofs.BCR2, PHY_BCR2_BIAS_EN);
+
+ /* Enable DP, LS, BIT clock output */
+ lvds_gcr = PHY_GCR_DP_CLK_OUT | PHY_GCR_LS_CLK_OUT | PHY_GCR_BIT_CLK_OUT;
+ lvds_set(lvds, phy->base + phy->ofs.GCR, lvds_gcr);
+
+ /* Power up all output dividers */
+ lvds_set(lvds, phy->base + phy->ofs.PLLTESTCR, PHY_PLLTESTCR_EN);
+ lvds_set(lvds, phy->base + phy->ofs.PLLCR1, PHY_PLLCR1_DIV_EN);
+
+ /* Set PHY in serial transmission mode */
+ lvds_set(lvds, phy->base + phy->ofs.SCR, PHY_SCR_TX_EN);
+
+ /* Enable the LVDS PLL & wait for its lock */
+ lvds_set(lvds, phy->base + phy->ofs.PLLCR1, PHY_PLLCR1_PLL_EN);
+ ret = readl_poll_timeout_atomic(lvds->base + phy->base + phy->ofs.PLLSR,
+ val, val & PHY_PLLSR_PLL_LOCK,
+ SLEEP_US, TIMEOUT_US);
+ if (ret)
+ drm_err(drm, "!TIMEOUT! waiting PLL, let's continue\n");
+
+ /* WCLKCR_SECND_CLKPIX_SEL is for dual link */
+ lvds_write(lvds, LVDS_WCLKCR, WCLKCR_SECND_CLKPIX_SEL);
+
+ lvds_set(lvds, phy->ofs.PLLTESTCR, PHY_PLLTESTCR_CLK_EN);
+
+ return ret;
+}
+
+static int pll_get_clkout_khz(int clkin_khz, int bdiv, int mdiv, int ndiv)
+{
+ int divisor = ndiv * bdiv;
+
+ /* Prevents from division by 0 */
+ if (!divisor)
+ return 0;
+
+ return clkin_khz * mdiv / divisor;
+}
+
+#define TDIV 70
+#define NDIV_MIN 2
+#define NDIV_MAX 6
+#define BDIV_MIN 2
+#define BDIV_MAX 6
+#define MDIV_MIN 1
+#define MDIV_MAX 1023
+
+static int lvds_pll_get_params(struct stm_lvds *lvds,
+ unsigned int clkin_khz, unsigned int clkout_khz,
+ unsigned int *bdiv, unsigned int *mdiv, unsigned int *ndiv)
+{
+ int delta, best_delta; /* all in khz */
+ int i, o, n;
+
+ /* Early checks preventing division by 0 & odd results */
+ if (clkin_khz <= 0 || clkout_khz <= 0)
+ return -EINVAL;
+
+ best_delta = 1000000; /* big started value (1000000khz) */
+
+ for (i = NDIV_MIN; i <= NDIV_MAX; i++) {
+ for (o = BDIV_MIN; o <= BDIV_MAX; o++) {
+ n = DIV_ROUND_CLOSEST(i * o * clkout_khz, clkin_khz);
+ /* Check ndiv according to vco range */
+ if (n < MDIV_MIN || n > MDIV_MAX)
+ continue;
+ /* Check if new delta is better & saves parameters */
+ delta = pll_get_clkout_khz(clkin_khz, i, n, o) - clkout_khz;
+ if (delta < 0)
+ delta = -delta;
+ if (delta < best_delta) {
+ *ndiv = i;
+ *mdiv = n;
+ *bdiv = o;
+ best_delta = delta;
+ }
+ /* fast return in case of "perfect result" */
+ if (!delta)
+ return 0;
+ }
+ }
+
+ return 0;
+}
+
+static void lvds_pll_config(struct stm_lvds *lvds, struct lvds_phy_info *phy)
+{
+ unsigned int pll_in_khz, bdiv = 0, mdiv = 0, ndiv = 0;
+ struct clk_hw *hwclk;
+ int multiplier;
+
+ /*
+ * The LVDS PHY includes a low power low jitter high performance and
+ * highly configuration Phase Locked Loop supporting integer and
+ * fractional multiplication ratios and Spread Spectrum Clocking. In
+ * integer mode, the only software supported feature for now, the PLL is
+ * made of a pre-divider NDIV, a feedback multiplier MDIV, followed by
+ * several post-dividers, each one with a specific application.
+ *
+ * ,------. ,-----. ,-----.
+ * Fref --> | NDIV | -Fpdf-> | PFD | --> | VCO | --------> Fvco
+ * `------' ,-> | | `-----' |
+ * | `-----' |
+ * | ,------. |
+ * `-------- | MDIV | <-----'
+ * `------'
+ *
+ * From the output of the VCO, the clock can be optionally extracted on
+ * the RCC clock observer, with a divider TDIV, for testing purpose, or
+ * is passed through a programmable post-divider BDIV. Finally, the
+ * frequency can be divided further with two fixed dividers.
+ *
+ * ,--------.
+ * ,-----> | DP div | ----------------> Fdp
+ * ,------. | `--------'
+ * Fvco --> | BDIV | ------------------------------------> Fbit
+ * | `------' ,------. |
+ * `-------------> | TDIV | --.---------------------> ClkObs
+ * '------' | ,--------.
+ * `--> | LS div | ------> Fls
+ * '--------'
+ *
+ * The LS and DP clock dividers operate at a fixed ratio of 7 and 3.5
+ * respectively with regards to fbit. LS divider converts the bit clock
+ * to a pixel clock per lane per clock sample (Fls). This is useful
+ * when used to generate a dot clock for the display unit RGB output,
+ * and DP divider is.
+ */
+
+ hwclk = __clk_get_hw(lvds->pllref_clk);
+ if (!hwclk)
+ return;
+
+ pll_in_khz = clk_hw_get_rate(hwclk) / 1000;
+
+ if (lvds_is_dual_link(lvds->link_type))
+ multiplier = 2;
+ else
+ multiplier = 1;
+
+ lvds_pll_get_params(lvds, pll_in_khz,
+ lvds->pixel_clock_rate * 7 / 1000 / multiplier,
+ &bdiv, &mdiv, &ndiv);
+
+ /* Set BDIV, MDIV and NDIV */
+ lvds_write(lvds, phy->base + phy->ofs.PLLCR2, ndiv << 16);
+ lvds_set(lvds, phy->base + phy->ofs.PLLCR2, bdiv);
+ lvds_write(lvds, phy->base + phy->ofs.PLLSDCR1, mdiv);
+
+ /* Hardcode TDIV as dynamic values are not yet implemented */
+ lvds_write(lvds, phy->base + phy->ofs.PLLTESTCR, TDIV << 16);
+
+ /*
+ * For now, PLL just needs to be in integer mode
+ * Fractional and spread spectrum clocking are not yet implemented
+ *
+ * PLL integer mode:
+ * - PMRY_PLL_TWG_STEP = PMRY_PLL_SD_INT_RATIO
+ * - EN_TWG = 0
+ * - EN_SD = 0
+ * - DOWN_SPREAD = 0
+ *
+ * PLL fractional mode:
+ * - EN_TWG = 0
+ * - EN_SD = 1
+ * - DOWN_SPREAD = 0
+ *
+ * Spread Spectrum Clocking
+ * - EN_TWG = 1
+ * - EN_SD = 1
+ */
+
+ /* Disable TWG and SD */
+ lvds_clear(lvds, phy->base + phy->ofs.PLLCR1, PHY_PLLCR1_EN_TWG | PHY_PLLCR1_EN_SD);
+
+ /* Power up bias and PLL dividers */
+ lvds_set(lvds, phy->base + phy->ofs.DCR, PHY_DCR_POWER_OK);
+ lvds_set(lvds, phy->base + phy->ofs.CMCR1, PHY_CMCR_CM_EN_DL);
+ lvds_set(lvds, phy->base + phy->ofs.CMCR2, PHY_CMCR_CM_EN_DL4);
+
+ /* Set up voltage mode */
+ lvds_set(lvds, phy->base + phy->ofs.PLLCPCR, 0x1);
+ lvds_set(lvds, phy->base + phy->ofs.BCR3, PHY_BCR3_VM_EN_DL);
+ lvds_set(lvds, phy->base + phy->ofs.BCR1, PHY_BCR1_EN_BIAS_DL);
+ /* Enable digital datalanes */
+ lvds_set(lvds, phy->base + phy->ofs.CFGCR, PHY_CFGCR_EN_DIG_DL);
+}
+
+static int lvds_pixel_clk_enable(struct clk_hw *hw)
+{
+ struct stm_lvds *lvds = container_of(hw, struct stm_lvds, lvds_ck_px);
+ struct drm_device *drm = lvds->lvds_bridge.dev;
+ struct lvds_phy_info *phy;
+ int ret;
+
+ ret = clk_prepare_enable(lvds->pclk);
+ if (ret) {
+ drm_err(drm, "Failed to enable lvds peripheral clk\n");
+ return ret;
+ }
+
+ ret = clk_prepare_enable(lvds->pllref_clk);
+ if (ret) {
+ drm_err(drm, "Failed to enable lvds reference clk\n");
+ clk_disable_unprepare(lvds->pclk);
+ return ret;
+ }
+
+ /* In case we are operating in dual link the second PHY is set before the primary PHY. */
+ if (lvds->secondary) {
+ phy = lvds->secondary;
+
+ /* Release LVDS PHY from reset mode */
+ lvds_set(lvds, phy->base + phy->ofs.GCR, PHY_GCR_DIV_RSTN | PHY_GCR_RSTZ);
+ lvds_pll_config(lvds, phy);
+
+ ret = lvds_pll_enable(lvds, phy);
+ if (ret) {
+ drm_err(drm, "Failed to enable secondary PHY PLL: %d\n", ret);
+ return ret;
+ }
+ }
+
+ if (lvds->primary) {
+ phy = lvds->primary;
+
+ /* Release LVDS PHY from reset mode */
+ lvds_set(lvds, phy->base + phy->ofs.GCR, PHY_GCR_DIV_RSTN | PHY_GCR_RSTZ);
+ lvds_pll_config(lvds, phy);
+
+ ret = lvds_pll_enable(lvds, phy);
+ if (ret) {
+ drm_err(drm, "Failed to enable primary PHY PLL: %d\n", ret);
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+static void lvds_pixel_clk_disable(struct clk_hw *hw)
+{
+ struct stm_lvds *lvds = container_of(hw, struct stm_lvds, lvds_ck_px);
+
+ /*
+ * For each PHY:
+ * Disable DP, LS, BIT clock outputs
+ * Shutdown the PLL
+ * Assert LVDS PHY in reset mode
+ */
+
+ if (lvds->primary) {
+ lvds_clear(lvds, lvds->primary->base + lvds->primary->ofs.GCR,
+ (PHY_GCR_DP_CLK_OUT | PHY_GCR_LS_CLK_OUT | PHY_GCR_BIT_CLK_OUT));
+ lvds_clear(lvds, lvds->primary->base + lvds->primary->ofs.PLLCR1,
+ PHY_PLLCR1_PLL_EN);
+ lvds_clear(lvds, lvds->primary->base + lvds->primary->ofs.GCR,
+ PHY_GCR_DIV_RSTN | PHY_GCR_RSTZ);
+ }
+
+ if (lvds->secondary) {
+ lvds_clear(lvds, lvds->secondary->base + lvds->secondary->ofs.GCR,
+ (PHY_GCR_DP_CLK_OUT | PHY_GCR_LS_CLK_OUT | PHY_GCR_BIT_CLK_OUT));
+ lvds_clear(lvds, lvds->secondary->base + lvds->secondary->ofs.PLLCR1,
+ PHY_PLLCR1_PLL_EN);
+ lvds_clear(lvds, lvds->secondary->base + lvds->secondary->ofs.GCR,
+ PHY_GCR_DIV_RSTN | PHY_GCR_RSTZ);
+ }
+
+ clk_disable_unprepare(lvds->pllref_clk);
+ clk_disable_unprepare(lvds->pclk);
+}
+
+static unsigned long lvds_pixel_clk_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct stm_lvds *lvds = container_of(hw, struct stm_lvds, lvds_ck_px);
+ struct drm_device *drm = lvds->lvds_bridge.dev;
+ unsigned int pll_in_khz, bdiv, mdiv, ndiv;
+ int ret, multiplier, pll_out_khz;
+ u32 val;
+
+ ret = clk_prepare_enable(lvds->pclk);
+ if (ret) {
+ drm_err(drm, "Failed to enable lvds peripheral clk\n");
+ return 0;
+ }
+
+ if (lvds_is_dual_link(lvds->link_type))
+ multiplier = 2;
+ else
+ multiplier = 1;
+
+ val = lvds_read(lvds, lvds->primary->base + lvds->primary->ofs.PLLCR2);
+ drm_dbg(drm, "val = %08x\n", val);
+
+ ndiv = (val & PHY_PLLCR2_NDIV) >> 16;
+ bdiv = (val & PHY_PLLCR2_BDIV) >> 0;
+
+ mdiv = (unsigned int)lvds_read(lvds,
+ lvds->primary->base + lvds->primary->ofs.PLLSDCR1);
+
+ pll_in_khz = (unsigned int)(parent_rate / 1000);
+
+ /* Compute values if not yet accessible */
+ if (val == 0 || mdiv == 0) {
+ lvds_pll_get_params(lvds, pll_in_khz,
+ lvds->pixel_clock_rate * 7 / 1000 / multiplier,
+ &bdiv, &mdiv, &ndiv);
+ }
+
+ pll_out_khz = pll_get_clkout_khz(pll_in_khz, bdiv, mdiv, ndiv);
+ drm_dbg(drm, "ndiv %d , bdiv %d, mdiv %d, pll_out_khz %d\n",
+ ndiv, bdiv, mdiv, pll_out_khz);
+
+ /*
+ * 1/7 because for each pixel in 1 lane there is 7 bits
+ * We want pixclk, not bitclk
+ */
+ lvds->pixel_clock_rate = pll_out_khz * 1000 * multiplier / 7;
+
+ clk_disable_unprepare(lvds->pclk);
+
+ return (unsigned long)lvds->pixel_clock_rate;
+}
+
+static long lvds_pixel_clk_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ struct stm_lvds *lvds = container_of(hw, struct stm_lvds, lvds_ck_px);
+ unsigned int pll_in_khz, bdiv = 0, mdiv = 0, ndiv = 0;
+ const struct drm_connector *connector;
+ const struct drm_display_mode *mode;
+ int multiplier;
+
+ connector = &lvds->connector;
+ if (!connector)
+ return -EINVAL;
+
+ if (list_empty(&connector->modes)) {
+ drm_dbg(connector->dev, "connector: empty modes list\n");
+ return -EINVAL;
+ }
+
+ mode = list_first_entry(&connector->modes,
+ struct drm_display_mode, head);
+
+ pll_in_khz = (unsigned int)(*parent_rate / 1000);
+
+ if (lvds_is_dual_link(lvds->link_type))
+ multiplier = 2;
+ else
+ multiplier = 1;
+
+ lvds_pll_get_params(lvds, pll_in_khz, mode->clock * 7 / multiplier, &bdiv, &mdiv, &ndiv);
+
+ /*
+ * 1/7 because for each pixel in 1 lane there is 7 bits
+ * We want pixclk, not bitclk
+ */
+ lvds->pixel_clock_rate = (unsigned long)pll_get_clkout_khz(pll_in_khz, bdiv, mdiv, ndiv)
+ * 1000 * multiplier / 7;
+
+ return lvds->pixel_clock_rate;
+}
+
+static const struct clk_ops lvds_pixel_clk_ops = {
+ .enable = lvds_pixel_clk_enable,
+ .disable = lvds_pixel_clk_disable,
+ .recalc_rate = lvds_pixel_clk_recalc_rate,
+ .round_rate = lvds_pixel_clk_round_rate,
+};
+
+static const struct clk_init_data clk_data = {
+ .name = "clk_pix_lvds",
+ .ops = &lvds_pixel_clk_ops,
+ .parent_names = (const char * []) {"ck_ker_lvdsphy"},
+ .num_parents = 1,
+ .flags = CLK_IGNORE_UNUSED,
+};
+
+static void lvds_pixel_clk_unregister(void *data)
+{
+ struct stm_lvds *lvds = data;
+
+ of_clk_del_provider(lvds->dev->of_node);
+ clk_hw_unregister(&lvds->lvds_ck_px);
+}
+
+static int lvds_pixel_clk_register(struct stm_lvds *lvds)
+{
+ struct device_node *node = lvds->dev->of_node;
+ int ret;
+
+ lvds->lvds_ck_px.init = &clk_data;
+
+ /* set the rate by default at 148500000 */
+ lvds->pixel_clock_rate = 148500000;
+
+ ret = clk_hw_register(lvds->dev, &lvds->lvds_ck_px);
+ if (ret)
+ return ret;
+
+ ret = of_clk_add_hw_provider(node, of_clk_hw_simple_get,
+ &lvds->lvds_ck_px);
+ if (ret)
+ clk_hw_unregister(&lvds->lvds_ck_px);
+
+ return ret;
+}
+
+/*
+ * Host configuration related
+ */
+static void lvds_config_data_mapping(struct stm_lvds *lvds)
+{
+ struct drm_device *drm = lvds->lvds_bridge.dev;
+ const struct drm_display_info *info;
+ enum lvds_pixel (*bitmap)[7];
+ u32 lvds_dmlcr, lvds_dmmcr;
+ int i;
+
+ info = &(&lvds->connector)->display_info;
+ if (!info->num_bus_formats || !info->bus_formats) {
+ drm_warn(drm, "No LVDS bus format reported\n");
+ return;
+ }
+
+ switch (info->bus_formats[0]) {
+ case MEDIA_BUS_FMT_RGB666_1X7X3_SPWG: /* VESA-RGB666 */
+ drm_warn(drm, "Pixel format with data mapping not yet supported.\n");
+ return;
+ case MEDIA_BUS_FMT_RGB888_1X7X4_SPWG: /* VESA-RGB888 */
+ bitmap = lvds_bitmap_vesa_rgb888;
+ break;
+ case MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA: /* JEIDA-RGB888 */
+ bitmap = lvds_bitmap_jeida_rgb888;
+ break;
+ default:
+ drm_warn(drm, "Unsupported LVDS bus format 0x%04x\n", info->bus_formats[0]);
+ return;
+ }
+
+ /* Set bitmap for each lane */
+ for (i = 0; i < 5; i++) {
+ lvds_dmlcr = ((bitmap[i][0])
+ + (bitmap[i][1] << 5)
+ + (bitmap[i][2] << 10)
+ + (bitmap[i][3] << 15));
+ lvds_dmmcr = ((bitmap[i][4])
+ + (bitmap[i][5] << 5)
+ + (bitmap[i][6] << 10));
+
+ lvds_write(lvds, LVDS_DMLCR(i), lvds_dmlcr);
+ lvds_write(lvds, LVDS_DMMCR(i), lvds_dmmcr);
+ }
+}
+
+static void lvds_config_mode(struct stm_lvds *lvds)
+{
+ u32 bus_flags, lvds_cr = 0, lvds_cdl1cr = 0, lvds_cdl2cr = 0;
+ const struct drm_display_mode *mode;
+ const struct drm_connector *connector;
+
+ connector = &lvds->connector;
+ if (!connector)
+ return;
+
+ if (list_empty(&connector->modes)) {
+ drm_dbg(connector->dev, "connector: empty modes list\n");
+ return;
+ }
+
+ bus_flags = connector->display_info.bus_flags;
+ mode = list_first_entry(&connector->modes,
+ struct drm_display_mode, head);
+
+ lvds_clear(lvds, LVDS_CR, CR_LKMOD);
+ lvds_clear(lvds, LVDS_CDL1CR, CDLCRx_DISTR0 | CDLCRx_DISTR1 | CDLCRx_DISTR2 |
+ CDLCRx_DISTR3 | CDLCRx_DISTR4);
+ lvds_clear(lvds, LVDS_CDL2CR, CDLCRx_DISTR0 | CDLCRx_DISTR1 | CDLCRx_DISTR2 |
+ CDLCRx_DISTR3 | CDLCRx_DISTR4);
+
+ /* Set channel distribution */
+ if (lvds->primary)
+ lvds_cdl1cr = CDL1CR_DEFAULT;
+
+ if (lvds->secondary) {
+ lvds_cr |= CR_LKMOD;
+ lvds_cdl2cr = CDL2CR_DEFAULT;
+ }
+
+ /* Set signal polarity */
+ if (bus_flags & DRM_BUS_FLAG_DE_LOW)
+ lvds_cr |= CR_DEPOL;
+
+ if (mode->flags & DRM_MODE_FLAG_NHSYNC)
+ lvds_cr |= CR_HSPOL;
+
+ if (mode->flags & DRM_MODE_FLAG_NVSYNC)
+ lvds_cr |= CR_VSPOL;
+
+ switch (lvds->link_type) {
+ case LVDS_DUAL_LINK_EVEN_ODD_PIXELS: /* LKPHA = 0 */
+ lvds_cr &= ~CR_LKPHA;
+ break;
+ case LVDS_DUAL_LINK_ODD_EVEN_PIXELS: /* LKPHA = 1 */
+ lvds_cr |= CR_LKPHA;
+ break;
+ default:
+ drm_notice(lvds->lvds_bridge.dev, "No phase precised, setting default\n");
+ lvds_cr &= ~CR_LKPHA;
+ break;
+ }
+
+ /* Write config to registers */
+ lvds_set(lvds, LVDS_CR, lvds_cr);
+ lvds_write(lvds, LVDS_CDL1CR, lvds_cdl1cr);
+ lvds_write(lvds, LVDS_CDL2CR, lvds_cdl2cr);
+}
+
+static int lvds_connector_get_modes(struct drm_connector *connector)
+{
+ struct stm_lvds *lvds = connector_to_stm_lvds(connector);
+
+ return drm_panel_get_modes(lvds->panel, connector);
+}
+
+static int lvds_connector_atomic_check(struct drm_connector *connector,
+ struct drm_atomic_state *state)
+{
+ const struct drm_display_mode *panel_mode;
+ struct drm_connector_state *conn_state;
+ struct drm_crtc_state *crtc_state;
+
+ conn_state = drm_atomic_get_new_connector_state(state, connector);
+ if (!conn_state)
+ return -EINVAL;
+
+ if (list_empty(&connector->modes)) {
+ drm_dbg(connector->dev, "connector: empty modes list\n");
+ return -EINVAL;
+ }
+
+ if (!conn_state->crtc)
+ return -EINVAL;
+
+ panel_mode = list_first_entry(&connector->modes,
+ struct drm_display_mode, head);
+
+ /* We're not allowed to modify the resolution. */
+ crtc_state = drm_atomic_get_crtc_state(state, conn_state->crtc);
+ if (IS_ERR(crtc_state))
+ return PTR_ERR(crtc_state);
+
+ if (crtc_state->mode.hdisplay != panel_mode->hdisplay ||
+ crtc_state->mode.vdisplay != panel_mode->vdisplay)
+ return -EINVAL;
+
+ /* The flat panel mode is fixed, just copy it to the adjusted mode. */
+ drm_mode_copy(&crtc_state->adjusted_mode, panel_mode);
+
+ return 0;
+}
+
+static const struct drm_connector_helper_funcs lvds_conn_helper_funcs = {
+ .get_modes = lvds_connector_get_modes,
+ .atomic_check = lvds_connector_atomic_check,
+};
+
+static const struct drm_connector_funcs lvds_conn_funcs = {
+ .reset = drm_atomic_helper_connector_reset,
+ .fill_modes = drm_helper_probe_single_connector_modes,
+ .destroy = drm_connector_cleanup,
+ .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
+ .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
+};
+
+static int lvds_attach(struct drm_bridge *bridge,
+ enum drm_bridge_attach_flags flags)
+{
+ struct stm_lvds *lvds = bridge_to_stm_lvds(bridge);
+ struct drm_connector *connector = &lvds->connector;
+ struct drm_encoder *encoder = bridge->encoder;
+ int ret;
+
+ if (!bridge->encoder) {
+ drm_err(bridge->dev, "Parent encoder object not found\n");
+ return -ENODEV;
+ }
+
+ /* Set the encoder type as caller does not know it */
+ bridge->encoder->encoder_type = DRM_MODE_ENCODER_LVDS;
+
+ /* No cloning support */
+ bridge->encoder->possible_clones = 0;
+
+ /* If we have a next bridge just attach it. */
+ if (lvds->next_bridge)
+ return drm_bridge_attach(bridge->encoder, lvds->next_bridge,
+ bridge, flags);
+
+ if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
+ drm_err(bridge->dev, "Fix bridge driver to make connector optional!");
+ return -EINVAL;
+ }
+
+ /* Otherwise if we have a panel, create a connector. */
+ if (!lvds->panel)
+ return 0;
+
+ ret = drm_connector_init(bridge->dev, connector,
+ &lvds_conn_funcs, DRM_MODE_CONNECTOR_LVDS);
+ if (ret < 0)
+ return ret;
+
+ drm_connector_helper_add(connector, &lvds_conn_helper_funcs);
+
+ ret = drm_connector_attach_encoder(connector, encoder);
+
+ return ret;
+}
+
+static void lvds_atomic_enable(struct drm_bridge *bridge,
+ struct drm_bridge_state *old_bridge_state)
+{
+ struct drm_atomic_state *state = old_bridge_state->base.state;
+ struct stm_lvds *lvds = bridge_to_stm_lvds(bridge);
+ struct drm_connector_state *conn_state;
+ struct drm_connector *connector;
+ int ret;
+
+ ret = clk_prepare_enable(lvds->pclk);
+ if (ret) {
+ drm_err(bridge->dev, "Failed to enable lvds peripheral clk\n");
+ return;
+ }
+
+ connector = drm_atomic_get_new_connector_for_encoder(state, bridge->encoder);
+ if (!connector)
+ return;
+
+ conn_state = drm_atomic_get_new_connector_state(state, connector);
+ if (!conn_state)
+ return;
+
+ lvds_config_mode(lvds);
+
+ /* Set Data Mapping */
+ lvds_config_data_mapping(lvds);
+
+ /* Turn the output on. */
+ lvds_set(lvds, LVDS_CR, CR_LVDSEN);
+
+ if (lvds->panel) {
+ drm_panel_prepare(lvds->panel);
+ drm_panel_enable(lvds->panel);
+ }
+}
+
+static void lvds_atomic_disable(struct drm_bridge *bridge,
+ struct drm_bridge_state *old_bridge_state)
+{
+ struct stm_lvds *lvds = bridge_to_stm_lvds(bridge);
+
+ if (lvds->panel) {
+ drm_panel_disable(lvds->panel);
+ drm_panel_unprepare(lvds->panel);
+ }
+
+ /* Disable LVDS module */
+ lvds_clear(lvds, LVDS_CR, CR_LVDSEN);
+
+ clk_disable_unprepare(lvds->pclk);
+}
+
+static const struct drm_bridge_funcs lvds_bridge_funcs = {
+ .attach = lvds_attach,
+ .atomic_enable = lvds_atomic_enable,
+ .atomic_disable = lvds_atomic_disable,
+ .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
+ .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
+ .atomic_reset = drm_atomic_helper_bridge_reset,
+};
+
+static int lvds_probe(struct platform_device *pdev)
+{
+ struct device_node *port1, *port2, *remote;
+ struct device *dev = &pdev->dev;
+ struct reset_control *rstc;
+ struct stm_lvds *lvds;
+ int ret, dual_link;
+
+ dev_dbg(dev, "Probing LVDS driver...\n");
+
+ lvds = devm_kzalloc(dev, sizeof(*lvds), GFP_KERNEL);
+ if (!lvds)
+ return -ENOMEM;
+
+ lvds->dev = dev;
+
+ ret = drm_of_find_panel_or_bridge(dev->of_node, 1, 0,
+ &lvds->panel, &lvds->next_bridge);
+ if (ret) {
+ dev_err_probe(dev, ret, "Panel not found\n");
+ return ret;
+ }
+
+ lvds->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(lvds->base)) {
+ ret = PTR_ERR(lvds->base);
+ dev_err(dev, "Unable to get regs %d\n", ret);
+ return ret;
+ }
+
+ lvds->pclk = devm_clk_get(dev, "pclk");
+ if (IS_ERR(lvds->pclk)) {
+ ret = PTR_ERR(lvds->pclk);
+ dev_err(dev, "Unable to get peripheral clock: %d\n", ret);
+ return ret;
+ }
+
+ ret = clk_prepare_enable(lvds->pclk);
+ if (ret) {
+ dev_err(dev, "%s: Failed to enable peripheral clk\n", __func__);
+ return ret;
+ }
+
+ rstc = devm_reset_control_get_exclusive(dev, NULL);
+
+ if (IS_ERR(rstc)) {
+ ret = PTR_ERR(rstc);
+ goto err_lvds_probe;
+ }
+
+ reset_control_assert(rstc);
+ usleep_range(10, 20);
+ reset_control_deassert(rstc);
+
+ port1 = of_graph_get_port_by_id(dev->of_node, 1);
+ port2 = of_graph_get_port_by_id(dev->of_node, 2);
+ dual_link = drm_of_lvds_get_dual_link_pixel_order(port1, port2);
+
+ switch (dual_link) {
+ case DRM_LVDS_DUAL_LINK_ODD_EVEN_PIXELS:
+ lvds->link_type = LVDS_DUAL_LINK_ODD_EVEN_PIXELS;
+ lvds->primary = &lvds_phy_16ff_primary;
+ lvds->secondary = &lvds_phy_16ff_secondary;
+ break;
+ case DRM_LVDS_DUAL_LINK_EVEN_ODD_PIXELS:
+ lvds->link_type = LVDS_DUAL_LINK_EVEN_ODD_PIXELS;
+ lvds->primary = &lvds_phy_16ff_primary;
+ lvds->secondary = &lvds_phy_16ff_secondary;
+ break;
+ case -EINVAL:
+ /*
+ * drm_of_lvds_get_dual_pixel_order returns 4 possible values.
+ * In the case where the returned value is an error, it can be
+ * either ENODEV or EINVAL. Seeing the structure of this
+ * function, EINVAL means that either port1 or port2 is not
+ * present in the device tree.
+ * In that case, the lvds panel can be a single link panel, or
+ * there is a semantical error in the device tree code.
+ */
+ remote = of_get_next_available_child(port1, NULL);
+ if (remote) {
+ if (of_graph_get_remote_endpoint(remote)) {
+ lvds->link_type = LVDS_SINGLE_LINK_PRIMARY;
+ lvds->primary = &lvds_phy_16ff_primary;
+ lvds->secondary = NULL;
+ } else {
+ ret = -EINVAL;
+ }
+
+ of_node_put(remote);
+ }
+
+ remote = of_get_next_available_child(port2, NULL);
+ if (remote) {
+ if (of_graph_get_remote_endpoint(remote)) {
+ lvds->link_type = LVDS_SINGLE_LINK_SECONDARY;
+ lvds->primary = NULL;
+ lvds->secondary = &lvds_phy_16ff_secondary;
+ } else {
+ ret = (ret == -EINVAL) ? -EINVAL : 0;
+ }
+
+ of_node_put(remote);
+ }
+ break;
+ default:
+ ret = -EINVAL;
+ goto err_lvds_probe;
+ }
+ of_node_put(port1);
+ of_node_put(port2);
+
+ lvds->pllref_clk = devm_clk_get(dev, "ref");
+ if (IS_ERR(lvds->pllref_clk)) {
+ ret = PTR_ERR(lvds->pllref_clk);
+ dev_err(dev, "Unable to get reference clock: %d\n", ret);
+ goto err_lvds_probe;
+ }
+
+ ret = lvds_pixel_clk_register(lvds);
+ if (ret) {
+ dev_err(dev, "Failed to register LVDS pixel clock: %d\n", ret);
+ goto err_lvds_probe;
+ }
+
+ lvds->lvds_bridge.funcs = &lvds_bridge_funcs;
+ lvds->lvds_bridge.of_node = dev->of_node;
+ lvds->hw_version = lvds_read(lvds, LVDS_VERR);
+
+ dev_info(dev, "version 0x%02x initialized\n", lvds->hw_version);
+
+ drm_bridge_add(&lvds->lvds_bridge);
+
+ platform_set_drvdata(pdev, lvds);
+
+ clk_disable_unprepare(lvds->pclk);
+
+ return 0;
+
+err_lvds_probe:
+ clk_disable_unprepare(lvds->pclk);
+
+ return ret;
+}
+
+static int lvds_remove(struct platform_device *pdev)
+{
+ struct stm_lvds *lvds = platform_get_drvdata(pdev);
+
+ lvds_pixel_clk_unregister(lvds);
+
+ drm_bridge_remove(&lvds->lvds_bridge);
+
+ return 0;
+}
+
+static const struct of_device_id lvds_dt_ids[] = {
+ {
+ .compatible = "st,stm32-lvds",
+ .data = NULL
+ },
+ { /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, lvds_dt_ids);
+
+static struct platform_driver lvds_platform_driver = {
+ .probe = lvds_probe,
+ .remove = lvds_remove,
+ .driver = {
+ .name = "stm32-display-lvds",
+ .owner = THIS_MODULE,
+ .of_match_table = lvds_dt_ids,
+ },
+};
+
+module_platform_driver(lvds_platform_driver);
+
+MODULE_AUTHOR("Raphaël Gallais-Pou <raphael.gallais-pou@xxxxxxxxxxx>");
+MODULE_AUTHOR("Philippe Cornu <philippe.cornu@xxxxxxxxxxx>");
+MODULE_AUTHOR("Yannick Fertre <yannick.fertre@xxxxxxxxxxx>");
+MODULE_DESCRIPTION("STMicroelectronics LVDS Display Interface Transmitter DRM driver");
+MODULE_LICENSE("GPL");
--
2.25.1
