drm/sun4i: Add TCON TOP driver

As already described in DT binding, TCON TOP is responsible for
configuring display pipeline. In this initial driver focus is on HDMI
pipeline, so TVE and LCD configuration is not implemented.

Implemented features:
- HDMI source selection
- clock driver (TCON and DSI gating)
- connecting mixers and TCONS

Something similar also existed in previous SoCs, except that it was part
of first TCON.

Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180625120304.7543-6-jernej.skrabec@siol.net

drivers/gpu/drm/sun4i/Makefile

@@ -36,4 +36,4 @@ obj-$(CONFIG_DRM_SUN4I_BACKEND)	+= sun4i-backend.o sun4i-frontend.o
 obj-$(CONFIG_DRM_SUN4I_HDMI)	+= sun4i-drm-hdmi.o
 obj-$(CONFIG_DRM_SUN6I_DSI)	+= sun6i-dsi.o
 obj-$(CONFIG_DRM_SUN8I_DW_HDMI)	+= sun8i-drm-hdmi.o
-obj-$(CONFIG_DRM_SUN8I_MIXER)	+= sun8i-mixer.o
+obj-$(CONFIG_DRM_SUN8I_MIXER)	+= sun8i-mixer.o sun8i_tcon_top.o

drivers/gpu/drm/sun4i/sun8i_tcon_top.c

@@ -0,0 +1,300 @@
+// SPDX-License-Identifier: GPL-2.0+
+/* Copyright (c) 2018 Jernej Skrabec <jernej.skrabec@siol.net> */
+
+#include <drm/drmP.h>
+
+#include <dt-bindings/clock/sun8i-tcon-top.h>
+
+#include <linux/bitfield.h>
+#include <linux/component.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/of_graph.h>
+#include <linux/platform_device.h>
+
+#include "sun8i_tcon_top.h"
+
+static int sun8i_tcon_top_get_connected_ep_id(struct device_node *node,
+					      int port_id)
+{
+	struct device_node *ep, *remote, *port;
+	struct of_endpoint endpoint;
+
+	port = of_graph_get_port_by_id(node, port_id);
+	if (!port)
+		return -ENOENT;
+
+	for_each_available_child_of_node(port, ep) {
+		remote = of_graph_get_remote_port_parent(ep);
+		if (!remote)
+			continue;
+
+		if (of_device_is_available(remote)) {
+			of_graph_parse_endpoint(ep, &endpoint);
+
+			of_node_put(remote);
+
+			return endpoint.id;
+		}
+
+		of_node_put(remote);
+	}
+
+	return -ENOENT;
+}
+
+static struct clk_hw *sun8i_tcon_top_register_gate(struct device *dev,
+						   struct clk *parent,
+						   void __iomem *regs,
+						   spinlock_t *lock,
+						   u8 bit, int name_index)
+{
+	const char *clk_name, *parent_name;
+	int ret;
+
+	parent_name = __clk_get_name(parent);
+	ret = of_property_read_string_index(dev->of_node,
+					    "clock-output-names", name_index,
+					    &clk_name);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return clk_hw_register_gate(dev, clk_name, parent_name,
+				    CLK_SET_RATE_PARENT,
+				    regs + TCON_TOP_GATE_SRC_REG,
+				    bit, 0, lock);
+};
+
+static int sun8i_tcon_top_bind(struct device *dev, struct device *master,
+			       void *data)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct clk *dsi, *tcon_tv0, *tcon_tv1, *tve0, *tve1;
+	struct clk_hw_onecell_data *clk_data;
+	struct sun8i_tcon_top *tcon_top;
+	bool mixer0_unused = false;
+	struct resource *res;
+	void __iomem *regs;
+	int ret, i, id;
+	u32 val;
+
+	tcon_top = devm_kzalloc(dev, sizeof(*tcon_top), GFP_KERNEL);
+	if (!tcon_top)
+		return -ENOMEM;
+
+	clk_data = devm_kzalloc(dev, sizeof(*clk_data) +
+				sizeof(*clk_data->hws) * CLK_NUM,
+				GFP_KERNEL);
+	if (!clk_data)
+		return -ENOMEM;
+	tcon_top->clk_data = clk_data;
+
+	spin_lock_init(&tcon_top->reg_lock);
+
+	tcon_top->rst = devm_reset_control_get(dev, NULL);
+	if (IS_ERR(tcon_top->rst)) {
+		dev_err(dev, "Couldn't get our reset line\n");
+		return PTR_ERR(tcon_top->rst);
+	}
+
+	tcon_top->bus = devm_clk_get(dev, "bus");
+	if (IS_ERR(tcon_top->bus)) {
+		dev_err(dev, "Couldn't get the bus clock\n");
+		return PTR_ERR(tcon_top->bus);
+	}
+
+	dsi = devm_clk_get(dev, "dsi");
+	if (IS_ERR(dsi)) {
+		dev_err(dev, "Couldn't get the dsi clock\n");
+		return PTR_ERR(dsi);
+	}
+
+	tcon_tv0 = devm_clk_get(dev, "tcon-tv0");
+	if (IS_ERR(tcon_tv0)) {
+		dev_err(dev, "Couldn't get the tcon-tv0 clock\n");
+		return PTR_ERR(tcon_tv0);
+	}
+
+	tcon_tv1 = devm_clk_get(dev, "tcon-tv1");
+	if (IS_ERR(tcon_tv1)) {
+		dev_err(dev, "Couldn't get the tcon-tv1 clock\n");
+		return PTR_ERR(tcon_tv1);
+	}
+
+	tve0 = devm_clk_get(dev, "tve0");
+	if (IS_ERR(tve0)) {
+		dev_err(dev, "Couldn't get the tve0 clock\n");
+		return PTR_ERR(tve0);
+	}
+
+	tve1 = devm_clk_get(dev, "tve1");
+	if (IS_ERR(tve1)) {
+		dev_err(dev, "Couldn't get the tve1 clock\n");
+		return PTR_ERR(tve1);
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	regs = devm_ioremap_resource(dev, res);
+	if (IS_ERR(regs))
+		return PTR_ERR(regs);
+
+	ret = reset_control_deassert(tcon_top->rst);
+	if (ret) {
+		dev_err(dev, "Could not deassert ctrl reset control\n");
+		return ret;
+	}
+
+	ret = clk_prepare_enable(tcon_top->bus);
+	if (ret) {
+		dev_err(dev, "Could not enable bus clock\n");
+		goto err_assert_reset;
+	}
+
+	val = 0;
+
+	/* check if HDMI mux output is connected */
+	if (sun8i_tcon_top_get_connected_ep_id(dev->of_node, 5) >= 0) {
+		/* find HDMI input endpoint id, if it is connected at all*/
+		id = sun8i_tcon_top_get_connected_ep_id(dev->of_node, 4);
+		if (id >= 0)
+			val = FIELD_PREP(TCON_TOP_HDMI_SRC_MSK, id + 1);
+		else
+			DRM_DEBUG_DRIVER("TCON TOP HDMI input is not connected\n");
+	} else {
+		DRM_DEBUG_DRIVER("TCON TOP HDMI output is not connected\n");
+	}
+
+	writel(val, regs + TCON_TOP_GATE_SRC_REG);
+
+	val = 0;
+
+	/* process mixer0 mux output */
+	id = sun8i_tcon_top_get_connected_ep_id(dev->of_node, 1);
+	if (id >= 0) {
+		val = FIELD_PREP(TCON_TOP_PORT_DE0_MSK, id);
+	} else {
+		DRM_DEBUG_DRIVER("TCON TOP mixer0 output is not connected\n");
+		mixer0_unused = true;
+	}
+
+	/* process mixer1 mux output */
+	id = sun8i_tcon_top_get_connected_ep_id(dev->of_node, 3);
+	if (id >= 0) {
+		val |= FIELD_PREP(TCON_TOP_PORT_DE1_MSK, id);
+
+		/*
+		 * mixer0 mux has priority over mixer1 mux. We have to
+		 * make sure mixer0 doesn't overtake TCON from mixer1.
+		 */
+		if (mixer0_unused && id == 0)
+			val |= FIELD_PREP(TCON_TOP_PORT_DE0_MSK, 1);
+	} else {
+		DRM_DEBUG_DRIVER("TCON TOP mixer1 output is not connected\n");
+	}
+
+	writel(val, regs + TCON_TOP_PORT_SEL_REG);
+
+	/*
+	 * TCON TOP has two muxes, which select parent clock for each TCON TV
+	 * channel clock. Parent could be either TCON TV or TVE clock. For now
+	 * we leave this fixed to TCON TV, since TVE driver for R40 is not yet
+	 * implemented. Once it is, graph needs to be traversed to determine
+	 * if TVE is active on each TCON TV. If it is, mux should be switched
+	 * to TVE clock parent.
+	 */
+	clk_data->hws[CLK_TCON_TOP_TV0] =
+		sun8i_tcon_top_register_gate(dev, tcon_tv0, regs,
+					     &tcon_top->reg_lock,
+					     TCON_TOP_TCON_TV0_GATE, 0);
+
+	clk_data->hws[CLK_TCON_TOP_TV1] =
+		sun8i_tcon_top_register_gate(dev, tcon_tv1, regs,
+					     &tcon_top->reg_lock,
+					     TCON_TOP_TCON_TV1_GATE, 1);
+
+	clk_data->hws[CLK_TCON_TOP_DSI] =
+		sun8i_tcon_top_register_gate(dev, dsi, regs,
+					     &tcon_top->reg_lock,
+					     TCON_TOP_TCON_DSI_GATE, 2);
+
+	for (i = 0; i < CLK_NUM; i++)
+		if (IS_ERR(clk_data->hws[i])) {
+			ret = PTR_ERR(clk_data->hws[i]);
+			goto err_unregister_gates;
+		}
+
+	clk_data->num = CLK_NUM;
+
+	ret = of_clk_add_hw_provider(dev->of_node, of_clk_hw_onecell_get,
+				     clk_data);
+	if (ret)
+		goto err_unregister_gates;
+
+	dev_set_drvdata(dev, tcon_top);
+
+	return 0;
+
+err_unregister_gates:
+	for (i = 0; i < CLK_NUM; i++)
+		if (clk_data->hws[i])
+			clk_hw_unregister_gate(clk_data->hws[i]);
+	clk_disable_unprepare(tcon_top->bus);
+err_assert_reset:
+	reset_control_assert(tcon_top->rst);
+
+	return ret;
+}
+
+static void sun8i_tcon_top_unbind(struct device *dev, struct device *master,
+				  void *data)
+{
+	struct sun8i_tcon_top *tcon_top = dev_get_drvdata(dev);
+	struct clk_hw_onecell_data *clk_data = tcon_top->clk_data;
+	int i;
+
+	of_clk_del_provider(dev->of_node);
+	for (i = 0; i < CLK_NUM; i++)
+		clk_hw_unregister_gate(clk_data->hws[i]);
+
+	clk_disable_unprepare(tcon_top->bus);
+	reset_control_assert(tcon_top->rst);
+}
+
+static const struct component_ops sun8i_tcon_top_ops = {
+	.bind	= sun8i_tcon_top_bind,
+	.unbind	= sun8i_tcon_top_unbind,
+};
+
+static int sun8i_tcon_top_probe(struct platform_device *pdev)
+{
+	return component_add(&pdev->dev, &sun8i_tcon_top_ops);
+}
+
+static int sun8i_tcon_top_remove(struct platform_device *pdev)
+{
+	component_del(&pdev->dev, &sun8i_tcon_top_ops);
+
+	return 0;
+}
+
+/* sun4i_drv uses this list to check if a device node is a TCON TOP */
+const struct of_device_id sun8i_tcon_top_of_table[] = {
+	{ .compatible = "allwinner,sun8i-r40-tcon-top" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, sun8i_tcon_top_of_table);
+EXPORT_SYMBOL(sun8i_tcon_top_of_table);
+
+static struct platform_driver sun8i_tcon_top_platform_driver = {
+	.probe		= sun8i_tcon_top_probe,
+	.remove		= sun8i_tcon_top_remove,
+	.driver		= {
+		.name		= "sun8i-tcon-top",
+		.of_match_table	= sun8i_tcon_top_of_table,
+	},
+};
+module_platform_driver(sun8i_tcon_top_platform_driver);
+
+MODULE_AUTHOR("Jernej Skrabec <jernej.skrabec@siol.net>");
+MODULE_DESCRIPTION("Allwinner R40 TCON TOP driver");
+MODULE_LICENSE("GPL");

drivers/gpu/drm/sun4i/sun8i_tcon_top.h

@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/* Copyright (c) 2018 Jernej Skrabec <jernej.skrabec@siol.net> */
+
+#ifndef _SUN8I_TCON_TOP_H_
+#define _SUN8I_TCON_TOP_H_
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/reset.h>
+#include <linux/spinlock.h>
+
+#define TCON_TOP_TCON_TV_SETUP_REG	0x00
+
+#define TCON_TOP_PORT_SEL_REG		0x1C
+#define TCON_TOP_PORT_DE0_MSK			GENMASK(1, 0)
+#define TCON_TOP_PORT_DE1_MSK			GENMASK(5, 4)
+
+#define TCON_TOP_GATE_SRC_REG		0x20
+#define TCON_TOP_HDMI_SRC_MSK			GENMASK(29, 28)
+#define TCON_TOP_TCON_TV1_GATE			24
+#define TCON_TOP_TCON_TV0_GATE			20
+#define TCON_TOP_TCON_DSI_GATE			16
+
+#define CLK_NUM					3
+
+struct sun8i_tcon_top {
+	struct clk			*bus;
+	struct clk_hw_onecell_data	*clk_data;
+	struct reset_control		*rst;
+
+	/*
+	 * spinlock is used to synchronize access to same
+	 * register where multiple clock gates can be set.
+	 */
+	spinlock_t			reg_lock;
+};
+
+extern const struct of_device_id sun8i_tcon_top_of_table[];
+
+#endif /* _SUN8I_TCON_TOP_H_ */