[RFC 1/8] clk: sunxi: PLL2 support for sun4i, sun5i and sun7i

[emilio@elopez.com.ar (Emilio López)]

This patch adds support for PLL2 and derivates on A10 revision B and
higher, as well as on sun5i and sun7i SoCs. As this PLL is only used for
audio and requires good accuracy, we only support two known good rates.

Signed-off-by: Emilio L?pez <emilio@elopez.com.ar>
---
 drivers/clk/sunxi/Makefile       |   1 +
 drivers/clk/sunxi/clk-a10-pll2.c | 249 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 250 insertions(+)
 create mode 100644 drivers/clk/sunxi/clk-a10-pll2.c

diff --git a/drivers/clk/sunxi/Makefile b/drivers/clk/sunxi/Makefile
index 6850cba..dcd5709 100644
--- a/drivers/clk/sunxi/Makefile
+++ b/drivers/clk/sunxi/Makefile
@@ -4,6 +4,7 @@
 
 obj-y += clk-sunxi.o clk-factors.o
 obj-y += clk-a10-hosc.o
+obj-y += clk-a10-pll2.o
 obj-y += clk-a20-gmac.o
 
 obj-$(CONFIG_MFD_SUN6I_PRCM) += \
diff --git a/drivers/clk/sunxi/clk-a10-pll2.c b/drivers/clk/sunxi/clk-a10-pll2.c
new file mode 100644
index 0000000..bdbf1e9
--- /dev/null
+++ b/drivers/clk/sunxi/clk-a10-pll2.c
@@ -0,0 +1,249 @@
+/*
+ * Copyright 2013 Emilio L?pez
+ *
+ * Emilio L?pez <emilio@elopez.com.ar>
+ *
+ * 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>
+
+#define SUN4I_PLL2_ENABLE		31
+#define SUN4I_PLL2_POST_DIV		26
+#define SUN4I_PLL2_POST_DIV_MASK	0xF
+#define SUN4I_PLL2_N			8
+#define SUN4I_PLL2_N_MASK		0x7F
+#define SUN4I_PLL2_PRE_DIV		0
+#define SUN4I_PLL2_PRE_DIV_MASK		0x1F
+
+#define SUN4I_PLL2_OUTPUTS		4
+
+struct sun4i_pll2_clk {
+	struct clk_hw hw;
+	void __iomem *reg;
+};
+
+static inline struct sun4i_pll2_clk *to_sun4i_pll2_clk(struct clk_hw *hw)
+{
+	return container_of(hw, struct sun4i_pll2_clk, hw);
+}
+
+static unsigned long sun4i_pll2_1x_recalc_rate(struct clk_hw *hw,
+					    unsigned long parent_rate)
+{
+	struct sun4i_pll2_clk *clk = to_sun4i_pll2_clk(hw);
+	int n, prediv, postdiv;
+
+	u32 val = readl(clk->reg);
+	n = (val >> SUN4I_PLL2_N) & SUN4I_PLL2_N_MASK;
+	prediv = (val >> SUN4I_PLL2_PRE_DIV) & SUN4I_PLL2_PRE_DIV_MASK;
+	postdiv = (val >> SUN4I_PLL2_POST_DIV) & SUN4I_PLL2_POST_DIV_MASK;
+
+	/* 0 is a special case and means 1 */
+	if (n == 0)
+		n = 1;
+	if (prediv == 0)
+		prediv = 1;
+	if (postdiv == 0)
+		postdiv = 1;
+
+	return ((parent_rate * n) / prediv) / postdiv;
+}
+
+static unsigned long sun4i_pll2_8x_recalc_rate(struct clk_hw *hw,
+					       unsigned long parent_rate)
+{
+	struct sun4i_pll2_clk *clk = to_sun4i_pll2_clk(hw);
+	int n, prediv;
+
+	u32 val = readl(clk->reg);
+	n = (val >> SUN4I_PLL2_N) & SUN4I_PLL2_N_MASK;
+	prediv = (val >> SUN4I_PLL2_PRE_DIV) & SUN4I_PLL2_PRE_DIV_MASK;
+
+	/* 0 is a special case and means 1 */
+	if (n == 0)
+		n = 1;
+	if (prediv == 0)
+		prediv = 1;
+
+	return ((parent_rate * 2 * n) / prediv);
+}
+
+static unsigned long sun4i_pll2_4x_recalc_rate(struct clk_hw *hw,
+					       unsigned long parent_rate)
+{
+	return sun4i_pll2_8x_recalc_rate(hw, parent_rate / 2);
+}
+
+static unsigned long sun4i_pll2_2x_recalc_rate(struct clk_hw *hw,
+					       unsigned long parent_rate)
+{
+	return sun4i_pll2_8x_recalc_rate(hw, parent_rate / 4);
+}
+
+static long sun4i_pll2_1x_round_rate(struct clk_hw *hw, unsigned long rate,
+				     unsigned long *parent_rate)
+{
+	/*
+	 * There is only two interesting rates for the audio PLL, the
+	 * rest isn't really usable due to accuracy concerns. Therefore,
+	 * we specifically round to those rates here
+	 */
+	if (rate < 22579200)
+		return -EINVAL;
+
+	if (rate >= 22579200 && rate < 24576000)
+		return 22579200;
+
+	return 24576000;
+}
+
+static long sun4i_pll2_8x_round_rate(struct clk_hw *hw, unsigned long rate,
+				     unsigned long *parent_rate)
+{
+	/*
+	 * We should account for the postdiv that we're undoing on PLL2x8,
+	 * which is always 4 in the usable configurations. The division
+	 * by two is done because PLL2x8 also doubles the rate
+	 */
+	*parent_rate = (rate * 4) / 2;
+
+	return rate;
+}
+
+static long sun4i_pll2_4x_round_rate(struct clk_hw *hw, unsigned long rate,
+				     unsigned long *parent_rate)
+{
+	/* PLL2x4 * 2 = PLL2x8 */
+	return sun4i_pll2_8x_round_rate(hw, rate * 2, parent_rate);
+}
+
+static long sun4i_pll2_2x_round_rate(struct clk_hw *hw, unsigned long rate,
+				     unsigned long *parent_rate)
+{
+	/* PLL2x2 * 4 = PLL2x8 */
+	return sun4i_pll2_8x_round_rate(hw, rate * 4, parent_rate);
+}
+
+static int sun4i_pll2_set_rate(struct clk_hw *hw, unsigned long rate,
+			       unsigned long parent_rate)
+{
+	struct sun4i_pll2_clk *clk = to_sun4i_pll2_clk(hw);
+	u32 val = readl(clk->reg);
+
+	val &= ~(SUN4I_PLL2_N_MASK << SUN4I_PLL2_N);
+	val &= ~(SUN4I_PLL2_PRE_DIV_MASK << SUN4I_PLL2_PRE_DIV);
+	val &= ~(SUN4I_PLL2_POST_DIV_MASK << SUN4I_PLL2_POST_DIV);
+
+	val |= (21 << SUN4I_PLL2_PRE_DIV) | (4 << SUN4I_PLL2_POST_DIV);
+
+	if (rate == 22579200)
+		val |= (79 << SUN4I_PLL2_N);
+	else if (rate == 24576000)
+		val |= (86 << SUN4I_PLL2_N);
+	else
+		return -EINVAL;
+
+	writel(val, clk->reg);
+
+	return 0;
+}
+
+static struct clk_ops sun4i_pll2_ops_1x = {
+	.recalc_rate = sun4i_pll2_1x_recalc_rate,
+	.round_rate = sun4i_pll2_1x_round_rate,
+	.set_rate = sun4i_pll2_set_rate,
+};
+
+static struct clk_ops sun4i_pll2_ops_2x = {
+	.recalc_rate = sun4i_pll2_2x_recalc_rate,
+	.round_rate = sun4i_pll2_2x_round_rate,
+};
+
+static struct clk_ops sun4i_pll2_ops_4x = {
+	.recalc_rate = sun4i_pll2_4x_recalc_rate,
+	.round_rate = sun4i_pll2_4x_round_rate,
+};
+
+static struct clk_ops sun4i_pll2_ops_8x = {
+	.recalc_rate = sun4i_pll2_8x_recalc_rate,
+	.round_rate = sun4i_pll2_8x_round_rate,
+};
+
+static void __init sun4i_pll2_setup(struct device_node *np)
+{
+	const char *clk_name = np->name, *parent;
+	struct clk_onecell_data *clk_data;
+	struct sun4i_pll2_clk *pll2;
+	struct clk_gate *gate;
+	struct clk **clks;
+	void __iomem *reg;
+
+	pll2 = kzalloc(sizeof(*pll2), GFP_KERNEL);
+	gate = kzalloc(sizeof(*gate), GFP_KERNEL);
+	clk_data = kzalloc(sizeof(*clk_data), GFP_KERNEL);
+	clks = kcalloc(SUN4I_PLL2_OUTPUTS, sizeof(struct clk *), GFP_KERNEL);
+	if (!pll2 || !gate || !clk_data || !clks)
+		goto free_mem;
+
+	reg = of_iomap(np, 0);
+	parent = of_clk_get_parent_name(np, 0);
+	of_property_read_string_index(np, "clock-output-names", 0, &clk_name);
+
+	pll2->reg = reg;
+	gate->reg = reg;
+	gate->bit_idx = SUN4I_PLL2_ENABLE;
+
+	/* PLL2, also known as PLL2x1 */
+	of_property_read_string_index(np, "clock-output-names", 0, &clk_name);
+	clks[0] = clk_register_composite(NULL, clk_name, &parent, 1, NULL, NULL,
+					 &pll2->hw, &sun4i_pll2_ops_1x,
+					 &gate->hw, &clk_gate_ops, 0);
+	WARN_ON(IS_ERR(clks[0]));
+	parent = clk_name;
+
+	/* PLL2x2, 1/4 the rate of PLL2x8 */
+	of_property_read_string_index(np, "clock-output-names", 1, &clk_name);
+	clks[1] = clk_register_composite(NULL, clk_name, &parent, 1, NULL, NULL,
+					 &pll2->hw, &sun4i_pll2_ops_2x,
+					 NULL, NULL, CLK_SET_RATE_PARENT);
+	WARN_ON(IS_ERR(clks[1]));
+
+	/* PLL2x4, 1/2 the rate of PLL2x8 */
+	of_property_read_string_index(np, "clock-output-names", 2, &clk_name);
+	clks[2] = clk_register_composite(NULL, clk_name, &parent, 1, NULL, NULL,
+					 &pll2->hw, &sun4i_pll2_ops_4x,
+					 NULL, NULL, CLK_SET_RATE_PARENT);
+	WARN_ON(IS_ERR(clks[2]));
+
+	/* PLL2x8, double of PLL2 without the post divisor */
+	of_property_read_string_index(np, "clock-output-names", 3, &clk_name);
+	clks[3] = clk_register_composite(NULL, clk_name, &parent, 1, NULL, NULL,
+					 &pll2->hw, &sun4i_pll2_ops_8x,
+					 NULL, NULL, CLK_SET_RATE_PARENT);
+	WARN_ON(IS_ERR(clks[3]));
+
+	clk_data->clks = clks;
+	clk_data->clk_num = SUN4I_PLL2_OUTPUTS;
+	of_clk_add_provider(np, of_clk_src_onecell_get, clk_data);
+
+	return;
+
+free_mem:
+	kfree(pll2);
+	kfree(gate);
+	kfree(clk_data);
+	kfree(clks);
+}
+CLK_OF_DECLARE(sun4i_pll2, "allwinner,sun4i-a10-b-pll2-clk", sun4i_pll2_setup);
-- 
2.0.3