clk: sunxi: Add display and TCON0 clocks driver

The A10 SoCs and its relatives has a special clock controller to drive the
display engines (both frontend and backend), that have a lot in common with
the clock to drive the first TCON channel.

Add a driver to support both.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Rob Herring <robh@kernel.org>
[sboyd@codeaurora.org: Silence variable sized array warning]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

Documentation/devicetree/bindings/clock/sunxi.txt

@@ -64,6 +64,7 @@ Required properties:
 	"allwinner,sun8i-a83t-bus-gates-clk" - for the bus gates on A83T
 	"allwinner,sun8i-h3-bus-gates-clk" - for the bus gates on H3
 	"allwinner,sun9i-a80-apbs-gates-clk" - for the APBS gates on A80
+	"allwinner,sun4i-a10-display-clk" - for the display clocks on the A10
 	"allwinner,sun4i-a10-dram-gates-clk" - for the DRAM gates on A10
 	"allwinner,sun5i-a13-dram-gates-clk" - for the DRAM gates on A13
 	"allwinner,sun5i-a13-mbus-clk" - for the MBUS clock on A13
@@ -75,6 +76,7 @@ Required properties:
 	"allwinner,sun8i-a23-mbus-clk" - for the MBUS clock on A23
 	"allwinner,sun7i-a20-out-clk" - for the external output clocks
 	"allwinner,sun7i-a20-gmac-clk" - for the GMAC clock module on A20/A31
+	"allwinner,sun4i-a10-tcon-ch0-clk" - for the TCON channel 0 clock on the A10
 	"allwinner,sun4i-a10-tcon-ch1-clk" - for the TCON channel 1 clock on the A10
 	"allwinner,sun4i-a10-usb-clk" - for usb gates + resets on A10 / A20
 	"allwinner,sun5i-a13-usb-clk" - for usb gates + resets on A13

drivers/clk/sunxi/Makefile

@@ -11,6 +11,7 @@ obj-y += clk-a10-ve.o
 obj-y += clk-a20-gmac.o
 obj-y += clk-mod0.o
 obj-y += clk-simple-gates.o
+obj-y += clk-sun4i-display.o
 obj-y += clk-sun4i-pll3.o
 obj-y += clk-sun4i-tcon-ch1.o
 obj-y += clk-sun8i-bus-gates.o

drivers/clk/sunxi/clk-sun4i-display.c

@@ -0,0 +1,261 @@
+/*
+ * Copyright 2015 Maxime Ripard
+ *
+ * Maxime Ripard <maxime.ripard@free-electrons.com>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/kernel.h>
+#include <linux/of_address.h>
+#include <linux/reset-controller.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+struct sun4i_a10_display_clk_data {
+	bool	has_div;
+	u8	num_rst;
+	u8	parents;
+
+	u8	offset_en;
+	u8	offset_div;
+	u8	offset_mux;
+	u8	offset_rst;
+
+	u8	width_div;
+	u8	width_mux;
+};
+
+struct reset_data {
+	void __iomem			*reg;
+	spinlock_t			*lock;
+	struct reset_controller_dev	rcdev;
+	u8				offset;
+};
+
+static DEFINE_SPINLOCK(sun4i_a10_display_lock);
+
+static inline struct reset_data *rcdev_to_reset_data(struct reset_controller_dev *rcdev)
+{
+	return container_of(rcdev, struct reset_data, rcdev);
+};
+
+static int sun4i_a10_display_assert(struct reset_controller_dev *rcdev,
+				    unsigned long id)
+{
+	struct reset_data *data = rcdev_to_reset_data(rcdev);
+	unsigned long flags;
+	u32 reg;
+
+	spin_lock_irqsave(data->lock, flags);
+
+	reg = readl(data->reg);
+	writel(reg & ~BIT(data->offset + id), data->reg);
+
+	spin_unlock_irqrestore(data->lock, flags);
+
+	return 0;
+}
+
+static int sun4i_a10_display_deassert(struct reset_controller_dev *rcdev,
+				      unsigned long id)
+{
+	struct reset_data *data = rcdev_to_reset_data(rcdev);
+	unsigned long flags;
+	u32 reg;
+
+	spin_lock_irqsave(data->lock, flags);
+
+	reg = readl(data->reg);
+	writel(reg | BIT(data->offset + id), data->reg);
+
+	spin_unlock_irqrestore(data->lock, flags);
+
+	return 0;
+}
+
+static int sun4i_a10_display_status(struct reset_controller_dev *rcdev,
+				    unsigned long id)
+{
+	struct reset_data *data = rcdev_to_reset_data(rcdev);
+
+	return !(readl(data->reg) & BIT(data->offset + id));
+}
+
+static const struct reset_control_ops sun4i_a10_display_reset_ops = {
+	.assert		= sun4i_a10_display_assert,
+	.deassert	= sun4i_a10_display_deassert,
+	.status		= sun4i_a10_display_status,
+};
+
+static int sun4i_a10_display_reset_xlate(struct reset_controller_dev *rcdev,
+					 const struct of_phandle_args *spec)
+{
+	/* We only have a single reset signal */
+	return 0;
+}
+
+static void __init sun4i_a10_display_init(struct device_node *node,
+					  const struct sun4i_a10_display_clk_data *data)
+{
+	const char *parents[4];
+	const char *clk_name = node->name;
+	struct reset_data *reset_data;
+	struct clk_divider *div = NULL;
+	struct clk_gate *gate;
+	struct resource res;
+	struct clk_mux *mux;
+	void __iomem *reg;
+	struct clk *clk;
+	int ret;
+
+	of_property_read_string(node, "clock-output-names", &clk_name);
+
+	reg = of_io_request_and_map(node, 0, of_node_full_name(node));
+	if (IS_ERR(reg)) {
+		pr_err("%s: Could not map the clock registers\n", clk_name);
+		return;
+	}
+
+	ret = of_clk_parent_fill(node, parents, data->parents);
+	if (ret != data->parents) {
+		pr_err("%s: Could not retrieve the parents\n", clk_name);
+		goto unmap;
+	}
+
+	mux = kzalloc(sizeof(*mux), GFP_KERNEL);
+	if (!mux)
+		goto unmap;
+
+	mux->reg = reg;
+	mux->shift = data->offset_mux;
+	mux->mask = (1 << data->width_mux) - 1;
+	mux->lock = &sun4i_a10_display_lock;
+
+	gate = kzalloc(sizeof(*gate), GFP_KERNEL);
+	if (!gate)
+		goto free_mux;
+
+	gate->reg = reg;
+	gate->bit_idx = data->offset_en;
+	gate->lock = &sun4i_a10_display_lock;
+
+	if (data->has_div) {
+		div = kzalloc(sizeof(*div), GFP_KERNEL);
+		if (!div)
+			goto free_gate;
+
+		div->reg = reg;
+		div->shift = data->offset_div;
+		div->width = data->width_div;
+		div->lock = &sun4i_a10_display_lock;
+	}
+
+	clk = clk_register_composite(NULL, clk_name,
+				     parents, data->parents,
+				     &mux->hw, &clk_mux_ops,
+				     data->has_div ? &div->hw : NULL,
+				     data->has_div ? &clk_divider_ops : NULL,
+				     &gate->hw, &clk_gate_ops,
+				     0);
+	if (IS_ERR(clk)) {
+		pr_err("%s: Couldn't register the clock\n", clk_name);
+		goto free_div;
+	}
+
+	ret = of_clk_add_provider(node, of_clk_src_simple_get, clk);
+	if (ret) {
+		pr_err("%s: Couldn't register DT provider\n", clk_name);
+		goto free_clk;
+	}
+
+	if (!data->num_rst)
+		return;
+
+	reset_data = kzalloc(sizeof(*reset_data), GFP_KERNEL);
+	if (!reset_data)
+		goto free_of_clk;
+
+	reset_data->reg = reg;
+	reset_data->offset = data->offset_rst;
+	reset_data->lock = &sun4i_a10_display_lock;
+	reset_data->rcdev.nr_resets = data->num_rst;
+	reset_data->rcdev.ops = &sun4i_a10_display_reset_ops;
+	reset_data->rcdev.of_node = node;
+
+	if (data->num_rst == 1) {
+		reset_data->rcdev.of_reset_n_cells = 0;
+		reset_data->rcdev.of_xlate = &sun4i_a10_display_reset_xlate;
+	} else {
+		reset_data->rcdev.of_reset_n_cells = 1;
+	}
+
+	if (reset_controller_register(&reset_data->rcdev)) {
+		pr_err("%s: Couldn't register the reset controller\n",
+		       clk_name);
+		goto free_reset;
+	}
+
+	return;
+
+free_reset:
+	kfree(reset_data);
+free_of_clk:
+	of_clk_del_provider(node);
+free_clk:
+	clk_unregister_composite(clk);
+free_div:
+	kfree(div);
+free_gate:
+	kfree(gate);
+free_mux:
+	kfree(mux);
+unmap:
+	iounmap(reg);
+	of_address_to_resource(node, 0, &res);
+	release_mem_region(res.start, resource_size(&res));
+}
+
+static const struct sun4i_a10_display_clk_data sun4i_a10_tcon_ch0_data __initconst = {
+	.num_rst	= 2,
+	.parents	= 4,
+	.offset_en	= 31,
+	.offset_rst	= 29,
+	.offset_mux	= 24,
+	.width_mux	= 2,
+};
+
+static void __init sun4i_a10_tcon_ch0_setup(struct device_node *node)
+{
+	sun4i_a10_display_init(node, &sun4i_a10_tcon_ch0_data);
+}
+CLK_OF_DECLARE(sun4i_a10_tcon_ch0, "allwinner,sun4i-a10-tcon-ch0-clk",
+	       sun4i_a10_tcon_ch0_setup);
+
+static const struct sun4i_a10_display_clk_data sun4i_a10_display_data __initconst = {
+	.has_div	= true,
+	.num_rst	= 1,
+	.parents	= 3,
+	.offset_en	= 31,
+	.offset_rst	= 30,
+	.offset_mux	= 24,
+	.offset_div	= 0,
+	.width_mux	= 2,
+	.width_div	= 4,
+};
+
+static void __init sun4i_a10_display_setup(struct device_node *node)
+{
+	sun4i_a10_display_init(node, &sun4i_a10_display_data);
+}
+CLK_OF_DECLARE(sun4i_a10_display, "allwinner,sun4i-a10-display-clk",
+	       sun4i_a10_display_setup);