Hello Icenowy:

At 2025-12-25 00:12:01, "Icenowy Zheng" <[email protected]> wrote:
>From: Icenowy Zheng <[email protected]>
>
>T-Head TH1520 SoC contains a Synopsys DesignWare HDMI controller (paired
>with DesignWare HDMI TX PHY Gen2) that takes the "DP" output from the
>display controller.
>
>Add a driver for this controller utilizing the common DesignWare HDMI
>code in the kernel.
>
>Signed-off-by: Icenowy Zheng <[email protected]>
>Signed-off-by: Icenowy Zheng <[email protected]>
>---
>No changes in v3, v4.
>
>Changes in v2:
>- Created a new function to set PHY parameters and refactored the
>  control flow of the configure_phy callback.
>
> MAINTAINERS                             |   1 +
> drivers/gpu/drm/bridge/Kconfig          |  10 ++
> drivers/gpu/drm/bridge/Makefile         |   1 +
> drivers/gpu/drm/bridge/th1520-dw-hdmi.c | 173 ++++++++++++++++++++++++
> 4 files changed, 185 insertions(+)
> create mode 100644 drivers/gpu/drm/bridge/th1520-dw-hdmi.c


As this is a Synopsys DesignWare based IP, maybe it's better to put it under   
"drivers/gpu/drm/bridge/synopsys/"
Or just create a dir for thead, I think there will come other display related 
drivers for thead in the future.

>
>diff --git a/MAINTAINERS b/MAINTAINERS
>index 5b11839cba9de..fc04fc007a054 100644
>--- a/MAINTAINERS
>+++ b/MAINTAINERS
>@@ -22556,6 +22556,7 @@ F:     
>Documentation/devicetree/bindings/reset/thead,th1520-reset.yaml
> F:    arch/riscv/boot/dts/thead/
> F:    drivers/clk/thead/clk-th1520-ap.c
> F:    drivers/firmware/thead,th1520-aon.c
>+F:    drivers/gpu/drm/bridge/th1520-dw-hdmi.c
> F:    drivers/mailbox/mailbox-th1520.c
> F:    drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> F:    drivers/pinctrl/pinctrl-th1520.c
>diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
>index a250afd8d6622..8e19f5fb9ad7c 100644
>--- a/drivers/gpu/drm/bridge/Kconfig
>+++ b/drivers/gpu/drm/bridge/Kconfig
>@@ -335,6 +335,16 @@ config DRM_THINE_THC63LVD1024
>       help
>         Thine THC63LVD1024 LVDS/parallel converter driver.
> 
>+config DRM_THEAD_TH1520_DW_HDMI
>+      tristate "T-Head TH1520 DesignWare HDMI bridge"
>+      depends on OF
>+      depends on COMMON_CLK
>+      depends on ARCH_THEAD || COMPILE_TEST
>+      select DRM_DW_HDMI
>+      help
>+        Choose this to enable support for the internal HDMI bridge found
>+        on the T-Head TH1520 SoC.
>+
> config DRM_TOSHIBA_TC358762
>       tristate "TC358762 DSI/DPI bridge"
>       depends on OF
>diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
>index c7dc03182e592..085b5db45d6fd 100644
>--- a/drivers/gpu/drm/bridge/Makefile
>+++ b/drivers/gpu/drm/bridge/Makefile
>@@ -28,6 +28,7 @@ obj-$(CONFIG_DRM_SII902X) += sii902x.o
> obj-$(CONFIG_DRM_SII9234) += sii9234.o
> obj-$(CONFIG_DRM_SIMPLE_BRIDGE) += simple-bridge.o
> obj-$(CONFIG_DRM_SOLOMON_SSD2825) += ssd2825.o
>+obj-$(CONFIG_DRM_THEAD_TH1520_DW_HDMI) += th1520-dw-hdmi.o
> obj-$(CONFIG_DRM_THINE_THC63LVD1024) += thc63lvd1024.o
> obj-$(CONFIG_DRM_TOSHIBA_TC358762) += tc358762.o
> obj-$(CONFIG_DRM_TOSHIBA_TC358764) += tc358764.o
>diff --git a/drivers/gpu/drm/bridge/th1520-dw-hdmi.c 
>b/drivers/gpu/drm/bridge/th1520-dw-hdmi.c
>new file mode 100644
>index 0000000000000..389eead5f1c45
>--- /dev/null
>+++ b/drivers/gpu/drm/bridge/th1520-dw-hdmi.c
>@@ -0,0 +1,173 @@
>+// SPDX-License-Identifier: GPL-2.0+
>+/*
>+ * Copyright (C) 2025 Icenowy Zheng <[email protected]>
>+ *
>+ * Based on rcar_dw_hdmi.c, which is:
>+ *   Copyright (C) 2016 Renesas Electronics Corporation
>+ * Based on imx8mp-hdmi-tx.c, which is:
>+ *   Copyright (C) 2022 Pengutronix, Lucas Stach <[email protected]>
>+ */
>+
>+#include <linux/clk.h>
>+#include <linux/mod_devicetable.h>
>+#include <linux/module.h>
>+#include <linux/platform_device.h>
>+#include <linux/reset.h>
>+
>+#include <drm/bridge/dw_hdmi.h>
>+#include <drm/drm_modes.h>
>+
>+#define TH1520_HDMI_PHY_OPMODE_PLLCFG 0x06    /* Mode of operation and PLL 
>dividers */
>+#define TH1520_HDMI_PHY_CKSYMTXCTRL   0x09    /* Clock Symbol and Transmitter 
>Control Register */
>+#define TH1520_HDMI_PHY_VLEVCTRL      0x0e    /* Voltage Level Control 
>Register */
>+#define TH1520_HDMI_PHY_PLLCURRGMPCTRL        0x10    /* PLL current and Gmp 
>(conductance) */
>+#define TH1520_HDMI_PHY_PLLDIVCTRL    0x11    /* PLL dividers */
>+#define TH1520_HDMI_PHY_TXTERM                0x19    /* Transmission 
>Termination Register */
>+
>+struct th1520_hdmi_phy_params {
>+      unsigned long mpixelclock;
>+      u16 opmode_pllcfg;
>+      u16 pllcurrgmpctrl;
>+      u16 plldivctrl;
>+      u16 cksymtxctrl;
>+      u16 vlevctrl;
>+      u16 txterm;
>+};
>+
>+static const struct th1520_hdmi_phy_params th1520_hdmi_phy_params[] = {
>+      { 35500000,  0x0003, 0x0283, 0x0628, 0x8088, 0x01a0, 0x0007 },
>+      { 44900000,  0x0003, 0x0285, 0x0228, 0x8088, 0x01a0, 0x0007 },
>+      { 71000000,  0x0002, 0x1183, 0x0614, 0x8088, 0x01a0, 0x0007 },
>+      { 90000000,  0x0002, 0x1142, 0x0214, 0x8088, 0x01a0, 0x0007 },
>+      { 121750000, 0x0001, 0x20c0, 0x060a, 0x8088, 0x01a0, 0x0007 },
>+      { 165000000, 0x0001, 0x2080, 0x020a, 0x8088, 0x01a0, 0x0007 },
>+      { 198000000, 0x0000, 0x3040, 0x0605, 0x83c8, 0x0120, 0x0004 },
>+      { 297000000, 0x0000, 0x3041, 0x0205, 0x81dc, 0x0200, 0x0005 },
>+      { 371250000, 0x0640, 0x3041, 0x0205, 0x80f6, 0x0140, 0x0000 },
>+      { 495000000, 0x0640, 0x3080, 0x0005, 0x80f6, 0x0140, 0x0000 },
>+      { 594000000, 0x0640, 0x3080, 0x0005, 0x80fa, 0x01e0, 0x0004 },
>+};
>+
>+struct th1520_hdmi {
>+      struct dw_hdmi_plat_data plat_data;
>+      struct dw_hdmi *dw_hdmi;
>+      struct clk *pixclk;
>+      struct reset_control *mainrst, *prst;
>+};
>+
>+static enum drm_mode_status
>+th1520_hdmi_mode_valid(struct dw_hdmi *hdmi, void *data,
>+                     const struct drm_display_info *info,
>+                     const struct drm_display_mode *mode)
>+{
>+      /*
>+       * The maximum supported clock frequency is 594 MHz, as shown in the PHY
>+       * parameters table.
>+       */
>+      if (mode->clock > 594000)
>+              return MODE_CLOCK_HIGH;
>+
>+      return MODE_OK;
>+}
>+
>+static void th1520_hdmi_phy_set_params(struct dw_hdmi *hdmi,
>+                              const struct th1520_hdmi_phy_params *params)
>+{
>+      dw_hdmi_phy_i2c_write(hdmi, params->opmode_pllcfg,
>+                            TH1520_HDMI_PHY_OPMODE_PLLCFG);
>+      dw_hdmi_phy_i2c_write(hdmi, params->pllcurrgmpctrl,
>+                            TH1520_HDMI_PHY_PLLCURRGMPCTRL);
>+      dw_hdmi_phy_i2c_write(hdmi, params->plldivctrl,
>+                            TH1520_HDMI_PHY_PLLDIVCTRL);
>+      dw_hdmi_phy_i2c_write(hdmi, params->vlevctrl,
>+                            TH1520_HDMI_PHY_VLEVCTRL);
>+      dw_hdmi_phy_i2c_write(hdmi, params->cksymtxctrl,
>+                            TH1520_HDMI_PHY_CKSYMTXCTRL);
>+      dw_hdmi_phy_i2c_write(hdmi, params->txterm,
>+                            TH1520_HDMI_PHY_TXTERM);
>+}
>+
>+static int th1520_hdmi_phy_configure(struct dw_hdmi *hdmi, void *data,
>+                                   unsigned long mpixelclock)
>+{
>+      unsigned int i;
>+
>+      for (i = 0; i < ARRAY_SIZE(th1520_hdmi_phy_params); i++) {
>+              if (mpixelclock <= th1520_hdmi_phy_params[i].mpixelclock) {
>+                      th1520_hdmi_phy_set_params(hdmi,
>+                                                 &th1520_hdmi_phy_params[i]);
>+                      return 0;
>+              }
>+      }
>+
>+      return -EINVAL;
>+}
>+
>+static int th1520_dw_hdmi_probe(struct platform_device *pdev)
>+{
>+      struct th1520_hdmi *hdmi;
>+      struct dw_hdmi_plat_data *plat_data;
>+      struct device *dev = &pdev->dev;
>+
>+      hdmi = devm_kzalloc(dev, sizeof(*hdmi), GFP_KERNEL);
>+      if (!hdmi)
>+              return -ENOMEM;
>+
>+      plat_data = &hdmi->plat_data;
>+
>+      hdmi->pixclk = devm_clk_get_enabled(dev, "pix");
>+      if (IS_ERR(hdmi->pixclk))
>+              return dev_err_probe(dev, PTR_ERR(hdmi->pixclk),
>+                                   "Unable to get pixel clock\n");
>+
>+      hdmi->mainrst = devm_reset_control_get_exclusive_deasserted(dev, 
>"main");
>+      if (IS_ERR(hdmi->mainrst))
>+              return dev_err_probe(dev, PTR_ERR(hdmi->mainrst),
>+                                   "Unable to get main reset\n");
>+
>+      hdmi->prst = devm_reset_control_get_exclusive_deasserted(dev, "apb");
>+      if (IS_ERR(hdmi->prst))
>+              return dev_err_probe(dev, PTR_ERR(hdmi->prst),
>+                                   "Unable to get apb reset\n");
>+
>+      plat_data->output_port = 1;
>+      plat_data->mode_valid = th1520_hdmi_mode_valid;
>+      plat_data->configure_phy = th1520_hdmi_phy_configure;
>+      plat_data->priv_data = hdmi;
>+
>+      hdmi->dw_hdmi = dw_hdmi_probe(pdev, plat_data);
>+      if (IS_ERR(hdmi))
>+              return PTR_ERR(hdmi);
>+
>+      platform_set_drvdata(pdev, hdmi);
>+
>+      return 0;
>+}
>+
>+static void th1520_dw_hdmi_remove(struct platform_device *pdev)
>+{
>+      struct dw_hdmi *hdmi = platform_get_drvdata(pdev);
>+
>+      dw_hdmi_remove(hdmi);
>+}
>+
>+static const struct of_device_id th1520_dw_hdmi_of_table[] = {
>+      { .compatible = "thead,th1520-dw-hdmi" },
>+      { /* Sentinel */ },
>+};
>+MODULE_DEVICE_TABLE(of, th1520_dw_hdmi_of_table);
>+
>+static struct platform_driver th1520_dw_hdmi_platform_driver = {
>+      .probe          = th1520_dw_hdmi_probe,
>+      .remove         = th1520_dw_hdmi_remove,
>+      .driver         = {
>+              .name   = "th1520-dw-hdmi",
>+              .of_match_table = th1520_dw_hdmi_of_table,
>+      },
>+};
>+
>+module_platform_driver(th1520_dw_hdmi_platform_driver);
>+
>+MODULE_AUTHOR("Icenowy Zheng <[email protected]>");
>+MODULE_DESCRIPTION("T-Head TH1520 HDMI Encoder Driver");
>+MODULE_LICENSE("GPL");
>-- 
>2.52.0
>
>
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