drm/ingenic: Add dw-hdmi driver specialization for jz4780

A specialisation of the generic Synopsys HDMI driver is employed for
JZ4780 HDMI support. This requires a new driver, plus device tree and
configuration modifications.

Here we add Kconfig DRM_INGENIC_DW_HDMI, Makefile and driver code.

Note that there is no hpd-gpio installed on the CI20 board HDMI
connector. Hence there is no hpd detection by the connector driver
and we have to enable polling in the dw-hdmi core driver.

For that we need to set .poll_enabled but that struct component
can only be accessed by core code. Hence we use the public
setter function drm_kms_helper_hotplug_event() introduced before.

Also note that we disable Color Space Conversion since it is not
working on jz4780.
Signed-off-by: Paul Boddie <paul@boddie.org.uk>
Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Link: https://patchwork.freedesktop.org/patch/msgid/e5cdf9cd44bde52cce379cc830f2d6117ea15c32.1649330171.git.hns@goldelico.com

drivers/gpu/drm/ingenic/Kconfig

@@ -24,4 +24,13 @@ config DRM_INGENIC_IPU
 
 	  The Image Processing Unit (IPU) will appear as a second primary plane.
 
+config DRM_INGENIC_DW_HDMI
+	tristate "Ingenic specific support for Synopsys DW HDMI"
+	depends on MACH_JZ4780
+	select DRM_DW_HDMI
+	help
+	  Choose this option to enable Synopsys DesignWare HDMI based driver.
+	  If you want to enable HDMI on Ingenic JZ4780 based SoC, you should
+	  select this option.
+
 endif

drivers/gpu/drm/ingenic/Makefile

 obj-$(CONFIG_DRM_INGENIC) += ingenic-drm.o
 ingenic-drm-y = ingenic-drm-drv.o
 ingenic-drm-$(CONFIG_DRM_INGENIC_IPU) += ingenic-ipu.o
+obj-$(CONFIG_DRM_INGENIC_DW_HDMI) += ingenic-dw-hdmi.o

drivers/gpu/drm/ingenic/ingenic-dw-hdmi.c

+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2011-2013 Freescale Semiconductor, Inc.
+ * Copyright (C) 2019, 2020 Paul Boddie <paul@boddie.org.uk>
+ *
+ * Derived from dw_hdmi-imx.c with i.MX portions removed.
+ */
+
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+
+#include <drm/bridge/dw_hdmi.h>
+#include <drm/drm_of.h>
+#include <drm/drm_print.h>
+
+static const struct dw_hdmi_mpll_config ingenic_mpll_cfg[] = {
+	{ 45250000,  { { 0x01e0, 0x0000 }, { 0x21e1, 0x0000 }, { 0x41e2, 0x0000 } } },
+	{ 92500000,  { { 0x0140, 0x0005 }, { 0x2141, 0x0005 }, { 0x4142, 0x0005 } } },
+	{ 148500000, { { 0x00a0, 0x000a }, { 0x20a1, 0x000a }, { 0x40a2, 0x000a } } },
+	{ 216000000, { { 0x00a0, 0x000a }, { 0x2001, 0x000f }, { 0x4002, 0x000f } } },
+	{ ~0UL,      { { 0x0000, 0x0000 }, { 0x0000, 0x0000 }, { 0x0000, 0x0000 } } }
+};
+
+static const struct dw_hdmi_curr_ctrl ingenic_cur_ctr[] = {
+	/*pixelclk     bpp8    bpp10   bpp12 */
+	{ 54000000,  { 0x091c, 0x091c, 0x06dc } },
+	{ 58400000,  { 0x091c, 0x06dc, 0x06dc } },
+	{ 72000000,  { 0x06dc, 0x06dc, 0x091c } },
+	{ 74250000,  { 0x06dc, 0x0b5c, 0x091c } },
+	{ 118800000, { 0x091c, 0x091c, 0x06dc } },
+	{ 216000000, { 0x06dc, 0x0b5c, 0x091c } },
+	{ ~0UL,      { 0x0000, 0x0000, 0x0000 } },
+};
+
+/*
+ * Resistance term 133Ohm Cfg
+ * PREEMP config 0.00
+ * TX/CK level 10
+ */
+static const struct dw_hdmi_phy_config ingenic_phy_config[] = {
+	/*pixelclk   symbol   term   vlev */
+	{ 216000000, 0x800d, 0x0005, 0x01ad},
+	{ ~0UL,      0x0000, 0x0000, 0x0000}
+};
+
+static enum drm_mode_status
+ingenic_dw_hdmi_mode_valid(struct dw_hdmi *hdmi, void *data,
+			   const struct drm_display_info *info,
+			   const struct drm_display_mode *mode)
+{
+	if (mode->clock < 13500)
+		return MODE_CLOCK_LOW;
+	/* FIXME: Hardware is capable of 270MHz, but setup data is missing. */
+	if (mode->clock > 216000)
+		return MODE_CLOCK_HIGH;
+
+	return MODE_OK;
+}
+
+static struct dw_hdmi_plat_data ingenic_dw_hdmi_plat_data = {
+	.mpll_cfg   = ingenic_mpll_cfg,
+	.cur_ctr    = ingenic_cur_ctr,
+	.phy_config = ingenic_phy_config,
+	.mode_valid = ingenic_dw_hdmi_mode_valid,
+	.output_port	= 1,
+};
+
+static const struct of_device_id ingenic_dw_hdmi_dt_ids[] = {
+	{ .compatible = "ingenic,jz4780-dw-hdmi" },
+	{ /* Sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, ingenic_dw_hdmi_dt_ids);
+
+static void ingenic_dw_hdmi_cleanup(void *data)
+{
+	struct dw_hdmi *hdmi = (struct dw_hdmi *)data;
+
+	dw_hdmi_remove(hdmi);
+}
+
+static int ingenic_dw_hdmi_probe(struct platform_device *pdev)
+{
+	struct dw_hdmi *hdmi;
+
+	hdmi = dw_hdmi_probe(pdev, &ingenic_dw_hdmi_plat_data);
+	if (IS_ERR(hdmi))
+		return PTR_ERR(hdmi);
+
+	return devm_add_action_or_reset(&pdev->dev, ingenic_dw_hdmi_cleanup, hdmi);
+}
+
+static struct platform_driver ingenic_dw_hdmi_driver = {
+	.probe  = ingenic_dw_hdmi_probe,
+	.driver = {
+		.name = "dw-hdmi-ingenic",
+		.of_match_table = ingenic_dw_hdmi_dt_ids,
+	},
+};
+module_platform_driver(ingenic_dw_hdmi_driver);
+
+MODULE_DESCRIPTION("JZ4780 Specific DW-HDMI Driver Extension");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:dw-hdmi-ingenic");