clk: sunxi: Add TCON channel1 clock

The TCON is a controller generating the timings to output videos signals,
acting like both a CRTC and an encoder.

It has two channels depending on the output, each channel being driven by
its own clock (and own clock controller).

Add a driver for the channel 1 clock.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Stephen Boyd <sboyd@codeaurora.org>

Documentation/devicetree/bindings/clock/sunxi.txt

@@ -75,6 +75,7 @@ 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-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
 	"allwinner,sun6i-a31-usb-clk" - for usb gates + resets on A31

drivers/clk/sunxi/Makefile

@@ -12,6 +12,7 @@ obj-y += clk-a20-gmac.o
 obj-y += clk-mod0.o
 obj-y += clk-simple-gates.o
 obj-y += clk-sun4i-pll3.o
+obj-y += clk-sun4i-tcon-ch1.o
 obj-y += clk-sun8i-bus-gates.o
 obj-y += clk-sun8i-mbus.o
 obj-y += clk-sun9i-core.o

drivers/clk/sunxi/clk-sun4i-tcon-ch1.c

@@ -0,0 +1,300 @@
+/*
+ * 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/of.h>
+#include <linux/of_address.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#define TCON_CH1_SCLK2_PARENTS		4
+
+#define TCON_CH1_SCLK2_GATE_BIT		BIT(31)
+#define TCON_CH1_SCLK2_MUX_MASK		3
+#define TCON_CH1_SCLK2_MUX_SHIFT	24
+#define TCON_CH1_SCLK2_DIV_MASK		0xf
+#define TCON_CH1_SCLK2_DIV_SHIFT	0
+
+#define TCON_CH1_SCLK1_GATE_BIT		BIT(15)
+#define TCON_CH1_SCLK1_HALF_BIT		BIT(11)
+
+struct tcon_ch1_clk {
+	struct clk_hw	hw;
+	spinlock_t	lock;
+	void __iomem	*reg;
+};
+
+#define hw_to_tclk(hw)	container_of(hw, struct tcon_ch1_clk, hw)
+
+static void tcon_ch1_disable(struct clk_hw *hw)
+{
+	struct tcon_ch1_clk *tclk = hw_to_tclk(hw);
+	unsigned long flags;
+	u32 reg;
+
+	spin_lock_irqsave(&tclk->lock, flags);
+	reg = readl(tclk->reg);
+	reg &= ~(TCON_CH1_SCLK2_GATE_BIT | TCON_CH1_SCLK1_GATE_BIT);
+	writel(reg, tclk->reg);
+	spin_unlock_irqrestore(&tclk->lock, flags);
+}
+
+static int tcon_ch1_enable(struct clk_hw *hw)
+{
+	struct tcon_ch1_clk *tclk = hw_to_tclk(hw);
+	unsigned long flags;
+	u32 reg;
+
+	spin_lock_irqsave(&tclk->lock, flags);
+	reg = readl(tclk->reg);
+	reg |= TCON_CH1_SCLK2_GATE_BIT | TCON_CH1_SCLK1_GATE_BIT;
+	writel(reg, tclk->reg);
+	spin_unlock_irqrestore(&tclk->lock, flags);
+
+	return 0;
+}
+
+static int tcon_ch1_is_enabled(struct clk_hw *hw)
+{
+	struct tcon_ch1_clk *tclk = hw_to_tclk(hw);
+	u32 reg;
+
+	reg = readl(tclk->reg);
+	return reg & (TCON_CH1_SCLK2_GATE_BIT | TCON_CH1_SCLK1_GATE_BIT);
+}
+
+static u8 tcon_ch1_get_parent(struct clk_hw *hw)
+{
+	struct tcon_ch1_clk *tclk = hw_to_tclk(hw);
+	int num_parents = clk_hw_get_num_parents(hw);
+	u32 reg;
+
+	reg = readl(tclk->reg) >> TCON_CH1_SCLK2_MUX_SHIFT;
+	reg &= reg >> TCON_CH1_SCLK2_MUX_MASK;
+
+	if (reg >= num_parents)
+		return -EINVAL;
+
+	return reg;
+}
+
+static int tcon_ch1_set_parent(struct clk_hw *hw, u8 index)
+{
+	struct tcon_ch1_clk *tclk = hw_to_tclk(hw);
+	unsigned long flags;
+	u32 reg;
+
+	spin_lock_irqsave(&tclk->lock, flags);
+	reg = readl(tclk->reg);
+	reg &= ~(TCON_CH1_SCLK2_MUX_MASK << TCON_CH1_SCLK2_MUX_SHIFT);
+	reg |= index << TCON_CH1_SCLK2_MUX_SHIFT;
+	writel(reg, tclk->reg);
+	spin_unlock_irqrestore(&tclk->lock, flags);
+
+	return 0;
+};
+
+static unsigned long tcon_ch1_calc_divider(unsigned long rate,
+					   unsigned long parent_rate,
+					   u8 *div,
+					   bool *half)
+{
+	unsigned long best_rate = 0;
+	u8 best_m = 0, m;
+	bool is_double;
+
+	for (m = 1; m < 16; m++) {
+		u8 d;
+
+		for (d = 1; d < 3; d++) {
+			unsigned long tmp_rate;
+
+			tmp_rate = parent_rate / m / d;
+
+			if (tmp_rate > rate)
+				continue;
+
+			if (!best_rate ||
+			    (rate - tmp_rate) < (rate - best_rate)) {
+				best_rate = tmp_rate;
+				best_m = m;
+				is_double = d;
+			}
+		}
+	}
+
+	if (div && half) {
+		*div = best_m;
+		*half = is_double;
+	}
+
+	return best_rate;
+}
+
+static int tcon_ch1_determine_rate(struct clk_hw *hw,
+				   struct clk_rate_request *req)
+{
+	long best_rate = -EINVAL;
+	int i;
+
+	for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
+		unsigned long parent_rate;
+		unsigned long tmp_rate;
+		struct clk_hw *parent;
+
+		parent = clk_hw_get_parent_by_index(hw, i);
+		if (!parent)
+			continue;
+
+		parent_rate = clk_hw_get_rate(parent);
+
+		tmp_rate = tcon_ch1_calc_divider(req->rate, parent_rate,
+						 NULL, NULL);
+
+		if (best_rate < 0 ||
+		    (req->rate - tmp_rate) < (req->rate - best_rate)) {
+			best_rate = tmp_rate;
+			req->best_parent_rate = parent_rate;
+			req->best_parent_hw = parent;
+		}
+	}
+
+	if (best_rate < 0)
+		return best_rate;
+
+	req->rate = best_rate;
+	return 0;
+}
+
+static unsigned long tcon_ch1_recalc_rate(struct clk_hw *hw,
+					  unsigned long parent_rate)
+{
+	struct tcon_ch1_clk *tclk = hw_to_tclk(hw);
+	u32 reg;
+
+	reg = readl(tclk->reg);
+
+	parent_rate /= (reg & TCON_CH1_SCLK2_DIV_MASK) + 1;
+
+	if (reg & TCON_CH1_SCLK1_HALF_BIT)
+		parent_rate /= 2;
+
+	return parent_rate;
+}
+
+static int tcon_ch1_set_rate(struct clk_hw *hw, unsigned long rate,
+			     unsigned long parent_rate)
+{
+	struct tcon_ch1_clk *tclk = hw_to_tclk(hw);
+	unsigned long flags;
+	bool half;
+	u8 div_m;
+	u32 reg;
+
+	tcon_ch1_calc_divider(rate, parent_rate, &div_m, &half);
+
+	spin_lock_irqsave(&tclk->lock, flags);
+	reg = readl(tclk->reg);
+	reg &= ~(TCON_CH1_SCLK2_DIV_MASK | TCON_CH1_SCLK1_HALF_BIT);
+	reg |= (div_m - 1) & TCON_CH1_SCLK2_DIV_MASK;
+
+	if (half)
+		reg |= TCON_CH1_SCLK1_HALF_BIT;
+
+	writel(reg, tclk->reg);
+	spin_unlock_irqrestore(&tclk->lock, flags);
+
+	return 0;
+}
+
+static const struct clk_ops tcon_ch1_ops = {
+	.disable	= tcon_ch1_disable,
+	.enable		= tcon_ch1_enable,
+	.is_enabled	= tcon_ch1_is_enabled,
+
+	.get_parent	= tcon_ch1_get_parent,
+	.set_parent	= tcon_ch1_set_parent,
+
+	.determine_rate	= tcon_ch1_determine_rate,
+	.recalc_rate	= tcon_ch1_recalc_rate,
+	.set_rate	= tcon_ch1_set_rate,
+};
+
+static void __init tcon_ch1_setup(struct device_node *node)
+{
+	const char *parents[TCON_CH1_SCLK2_PARENTS];
+	const char *clk_name = node->name;
+	struct clk_init_data init;
+	struct tcon_ch1_clk *tclk;
+	struct resource res;
+	struct clk *clk;
+	void __iomem *reg;
+	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, TCON_CH1_SCLK2_PARENTS);
+	if (ret != TCON_CH1_SCLK2_PARENTS) {
+		pr_err("%s Could not retrieve the parents\n", clk_name);
+		goto err_unmap;
+	}
+
+	tclk = kzalloc(sizeof(*tclk), GFP_KERNEL);
+	if (!tclk)
+		goto err_unmap;
+
+	init.name = clk_name;
+	init.ops = &tcon_ch1_ops;
+	init.parent_names = parents;
+	init.num_parents = TCON_CH1_SCLK2_PARENTS;
+	init.flags = CLK_SET_RATE_PARENT;
+
+	tclk->reg = reg;
+	tclk->hw.init = &init;
+	spin_lock_init(&tclk->lock);
+
+	clk = clk_register(NULL, &tclk->hw);
+	if (IS_ERR(clk)) {
+		pr_err("%s: Couldn't register the clock\n", clk_name);
+		goto err_free_data;
+	}
+
+	ret = of_clk_add_provider(node, of_clk_src_simple_get, clk);
+	if (ret) {
+		pr_err("%s: Couldn't register our clock provider\n", clk_name);
+		goto err_unregister_clk;
+	}
+
+	return;
+
+err_unregister_clk:
+	clk_unregister(clk);
+err_free_data:
+	kfree(tclk);
+err_unmap:
+	iounmap(reg);
+	of_address_to_resource(node, 0, &res);
+	release_mem_region(res.start, resource_size(&res));
+}
+
+CLK_OF_DECLARE(tcon_ch1, "allwinner,sun4i-a10-tcon-ch1-clk",
+	       tcon_ch1_setup);