clk: sunxi: Add VE (Video Engine) module clock driver for sun[457]i

The video engine has its own special module clock, consisting of a clock
gate, configurable dividers, and a reset control.

On later (sun[68]i) families, the reset control is moved out of this
piece of hardware and grouped with reset controls of other peripherals.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Tested-by: Jens Kuske <jenskuske@gmail.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

Documentation/devicetree/bindings/clock/sunxi.txt

@@ -76,6 +76,7 @@ Required properties:
 	"allwinner,sun8i-h3-usb-clk" - for usb gates + resets on H3
 	"allwinner,sun9i-a80-usb-mod-clk" - for usb gates + resets on A80
 	"allwinner,sun9i-a80-usb-phy-clk" - for usb phy gates + resets on A80
+	"allwinner,sun4i-a10-ve-clk" - for the Video Engine clock
 
 Required properties for all clocks:
 - reg : shall be the control register address for the clock.
@@ -95,6 +96,9 @@ Required properties for all clocks:
 And "allwinner,*-usb-clk" clocks also require:
 - reset-cells : shall be set to 1
 
+The "allwinner,sun4i-a10-ve-clk" clock also requires:
+- reset-cells : shall be set to 0
+
 The "allwinner,sun9i-a80-mmc-config-clk" clock also requires:
 - #reset-cells : shall be set to 1
 - resets : shall be the reset control phandle for the mmc block.

drivers/clk/sunxi/Makefile

@@ -7,6 +7,7 @@ obj-y += clk-a10-codec.o
 obj-y += clk-a10-hosc.o
 obj-y += clk-a10-mod1.o
 obj-y += clk-a10-pll2.o
+obj-y += clk-a10-ve.o
 obj-y += clk-a20-gmac.o
 obj-y += clk-mod0.o
 obj-y += clk-simple-gates.o

drivers/clk/sunxi/clk-a10-ve.c

@@ -0,0 +1,171 @@
+/*
+ * Copyright 2015 Chen-Yu Tsai
+ *
+ * Chen-Yu Tsai <wens@csie.org>
+ *
+ * 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/of.h>
+#include <linux/of_address.h>
+#include <linux/reset-controller.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+static DEFINE_SPINLOCK(ve_lock);
+
+#define SUN4I_VE_ENABLE		31
+#define SUN4I_VE_DIVIDER_SHIFT	16
+#define SUN4I_VE_DIVIDER_WIDTH	3
+#define SUN4I_VE_RESET		0
+
+/**
+ * sunxi_ve_reset... - reset bit in ve clk registers handling
+ */
+
+struct ve_reset_data {
+	void __iomem			*reg;
+	spinlock_t			*lock;
+	struct reset_controller_dev	rcdev;
+};
+
+static int sunxi_ve_reset_assert(struct reset_controller_dev *rcdev,
+				 unsigned long id)
+{
+	struct ve_reset_data *data = container_of(rcdev,
+						  struct ve_reset_data,
+						  rcdev);
+	unsigned long flags;
+	u32 reg;
+
+	spin_lock_irqsave(data->lock, flags);
+
+	reg = readl(data->reg);
+	writel(reg & ~BIT(SUN4I_VE_RESET), data->reg);
+
+	spin_unlock_irqrestore(data->lock, flags);
+
+	return 0;
+}
+
+static int sunxi_ve_reset_deassert(struct reset_controller_dev *rcdev,
+				   unsigned long id)
+{
+	struct ve_reset_data *data = container_of(rcdev,
+						  struct ve_reset_data,
+						  rcdev);
+	unsigned long flags;
+	u32 reg;
+
+	spin_lock_irqsave(data->lock, flags);
+
+	reg = readl(data->reg);
+	writel(reg | BIT(SUN4I_VE_RESET), data->reg);
+
+	spin_unlock_irqrestore(data->lock, flags);
+
+	return 0;
+}
+
+static int sunxi_ve_of_xlate(struct reset_controller_dev *rcdev,
+			     const struct of_phandle_args *reset_spec)
+{
+	if (WARN_ON(reset_spec->args_count != 0))
+		return -EINVAL;
+
+	return 0;
+}
+
+static struct reset_control_ops sunxi_ve_reset_ops = {
+	.assert		= sunxi_ve_reset_assert,
+	.deassert	= sunxi_ve_reset_deassert,
+};
+
+static void __init sun4i_ve_clk_setup(struct device_node *node)
+{
+	struct clk *clk;
+	struct clk_divider *div;
+	struct clk_gate *gate;
+	struct ve_reset_data *reset_data;
+	const char *parent;
+	const char *clk_name = node->name;
+	void __iomem *reg;
+	int err;
+
+	reg = of_io_request_and_map(node, 0, of_node_full_name(node));
+	if (IS_ERR(reg))
+		return;
+
+	div = kzalloc(sizeof(*div), GFP_KERNEL);
+	if (!div)
+		goto err_unmap;
+
+	gate = kzalloc(sizeof(*gate), GFP_KERNEL);
+	if (!gate)
+		goto err_free_div;
+
+	of_property_read_string(node, "clock-output-names", &clk_name);
+	parent = of_clk_get_parent_name(node, 0);
+
+	gate->reg = reg;
+	gate->bit_idx = SUN4I_VE_ENABLE;
+	gate->lock = &ve_lock;
+
+	div->reg = reg;
+	div->shift = SUN4I_VE_DIVIDER_SHIFT;
+	div->width = SUN4I_VE_DIVIDER_WIDTH;
+	div->lock = &ve_lock;
+
+	clk = clk_register_composite(NULL, clk_name, &parent, 1,
+				     NULL, NULL,
+				     &div->hw, &clk_divider_ops,
+				     &gate->hw, &clk_gate_ops,
+				     CLK_SET_RATE_PARENT);
+	if (IS_ERR(clk))
+		goto err_free_gate;
+
+	err = of_clk_add_provider(node, of_clk_src_simple_get, clk);
+	if (err)
+		goto err_unregister_clk;
+
+	reset_data = kzalloc(sizeof(*reset_data), GFP_KERNEL);
+	if (!reset_data)
+		goto err_del_provider;
+
+	reset_data->reg = reg;
+	reset_data->lock = &ve_lock;
+	reset_data->rcdev.nr_resets = 1;
+	reset_data->rcdev.ops = &sunxi_ve_reset_ops;
+	reset_data->rcdev.of_node = node;
+	reset_data->rcdev.of_xlate = sunxi_ve_of_xlate;
+	reset_data->rcdev.of_reset_n_cells = 0;
+	err = reset_controller_register(&reset_data->rcdev);
+	if (err)
+		goto err_free_reset;
+
+	return;
+
+err_free_reset:
+	kfree(reset_data);
+err_del_provider:
+	of_clk_del_provider(node);
+err_unregister_clk:
+	clk_unregister(clk);
+err_free_gate:
+	kfree(gate);
+err_free_div:
+	kfree(div);
+err_unmap:
+	iounmap(reg);
+}
+CLK_OF_DECLARE(sun4i_ve, "allwinner,sun4i-a10-ve-clk",
+	       sun4i_ve_clk_setup);