clk: samsung: add clock driver for external clock outputs

This adds a driver for controlling the external clock outputs of
s3c24xx architectures including the dclk muxes and dividers.

The driver at the moment only supports the legacy non-dt boards using these
clock outputs. The clock-output control itself is part of the system-controller
mainly controlled by the pinctrl drivers. So it should most likely be
integrated there for dt platforms.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

2 files changed, 441 insertions, 0 deletions

diff --git a/drivers/clk/samsung/Makefile b/drivers/clk/samsung/Makefile
index 77313e27bc39..9892de4978e3 100644
--- a/drivers/clk/samsung/Makefile
+++ b/drivers/clk/samsung/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_SOC_EXYNOS5250)	+= clk-exynos5250.o
 obj-$(CONFIG_SOC_EXYNOS5420)	+= clk-exynos5420.o
 obj-$(CONFIG_SOC_EXYNOS5440)	+= clk-exynos5440.o
 obj-$(CONFIG_ARCH_EXYNOS)	+= clk-exynos-audss.o
+obj-$(CONFIG_S3C2410_COMMON_DCLK)+= clk-s3c2410-dclk.o
 obj-$(CONFIG_S3C2412_COMMON_CLK)+= clk-s3c2412.o
 obj-$(CONFIG_S3C2443_COMMON_CLK)+= clk-s3c2443.o
 obj-$(CONFIG_ARCH_S3C64XX)	+= clk-s3c64xx.o
diff --git a/drivers/clk/samsung/clk-s3c2410-dclk.c b/drivers/clk/samsung/clk-s3c2410-dclk.c
new file mode 100644
index 000000000000..8d8dff005c10
--- /dev/null
+++ b/drivers/clk/samsung/clk-s3c2410-dclk.c
@@ -0,0 +1,440 @@
+/*
+ * Copyright (c) 2013 Heiko Stuebner <heiko@sntech.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Common Clock Framework support for s3c24xx external clock output.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include "clk.h"
+
+/* legacy access to misccr, until dt conversion is finished */
+#include <mach/hardware.h>
+#include <mach/regs-gpio.h>
+
+#define MUX_DCLK0	0
+#define MUX_DCLK1	1
+#define DIV_DCLK0	2
+#define DIV_DCLK1	3
+#define GATE_DCLK0	4
+#define GATE_DCLK1	5
+#define MUX_CLKOUT0	6
+#define MUX_CLKOUT1	7
+#define DCLK_MAX_CLKS	(MUX_CLKOUT1 + 1)
+
+enum supported_socs {
+	S3C2410,
+	S3C2412,
+	S3C2440,
+	S3C2443,
+};
+
+struct s3c24xx_dclk_drv_data {
+	const char **clkout0_parent_names;
+	int clkout0_num_parents;
+	const char **clkout1_parent_names;
+	int clkout1_num_parents;
+	const char **mux_parent_names;
+	int mux_num_parents;
+};
+
+/*
+ * Clock for output-parent selection in misccr
+ */
+
+struct s3c24xx_clkout {
+	struct clk_hw		hw;
+	u32			mask;
+	u8			shift;
+};
+
+#define to_s3c24xx_clkout(_hw) container_of(_hw, struct s3c24xx_clkout, hw)
+
+static u8 s3c24xx_clkout_get_parent(struct clk_hw *hw)
+{
+	struct s3c24xx_clkout *clkout = to_s3c24xx_clkout(hw);
+	int num_parents = __clk_get_num_parents(hw->clk);
+	u32 val;
+
+	val = readl_relaxed(S3C24XX_MISCCR) >> clkout->shift;
+	val >>= clkout->shift;
+	val &= clkout->mask;
+
+	if (val >= num_parents)
+		return -EINVAL;
+
+	return val;
+}
+
+static int s3c24xx_clkout_set_parent(struct clk_hw *hw, u8 index)
+{
+	struct s3c24xx_clkout *clkout = to_s3c24xx_clkout(hw);
+	int ret = 0;
+
+	s3c2410_modify_misccr((clkout->mask << clkout->shift),
+			      (index << clkout->shift));
+
+	return ret;
+}
+
+const struct clk_ops s3c24xx_clkout_ops = {
+	.get_parent = s3c24xx_clkout_get_parent,
+	.set_parent = s3c24xx_clkout_set_parent,
+	.determine_rate = __clk_mux_determine_rate,
+};
+
+struct clk *s3c24xx_register_clkout(struct device *dev, const char *name,
+		const char **parent_names, u8 num_parents,
+		u8 shift, u32 mask)
+{
+	struct s3c24xx_clkout *clkout;
+	struct clk *clk;
+	struct clk_init_data init;
+
+	/* allocate the clkout */
+	clkout = kzalloc(sizeof(*clkout), GFP_KERNEL);
+	if (!clkout)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = name;
+	init.ops = &s3c24xx_clkout_ops;
+	init.flags = CLK_IS_BASIC;
+	init.parent_names = parent_names;
+	init.num_parents = num_parents;
+
+	clkout->shift = shift;
+	clkout->mask = mask;
+	clkout->hw.init = &init;
+
+	clk = clk_register(dev, &clkout->hw);
+
+	return clk;
+}
+
+/*
+ * dclk and clkout init
+ */
+
+struct s3c24xx_dclk {
+	struct device *dev;
+	void __iomem *base;
+	struct clk_onecell_data clk_data;
+	struct notifier_block dclk0_div_change_nb;
+	struct notifier_block dclk1_div_change_nb;
+	spinlock_t dclk_lock;
+	unsigned long reg_save;
+};
+
+#define to_s3c24xx_dclk0(x) \
+		container_of(x, struct s3c24xx_dclk, dclk0_div_change_nb)
+
+#define to_s3c24xx_dclk1(x) \
+		container_of(x, struct s3c24xx_dclk, dclk1_div_change_nb)
+
+PNAME(dclk_s3c2410_p) = { "pclk", "uclk" };
+PNAME(clkout0_s3c2410_p) = { "mpll", "upll", "fclk", "hclk", "pclk",
+			     "gate_dclk0" };
+PNAME(clkout1_s3c2410_p) = { "mpll", "upll", "fclk", "hclk", "pclk",
+			     "gate_dclk1" };
+
+PNAME(clkout0_s3c2412_p) = { "mpll", "upll", "rtc_clkout",
+			     "hclk", "pclk", "gate_dclk0" };
+PNAME(clkout1_s3c2412_p) = { "xti", "upll", "fclk", "hclk", "pclk",
+			     "gate_dclk1" };
+
+PNAME(clkout0_s3c2440_p) = { "xti", "upll", "fclk", "hclk", "pclk",
+			     "gate_dclk0" };
+PNAME(clkout1_s3c2440_p) = { "mpll", "upll", "rtc_clkout",
+			     "hclk", "pclk", "gate_dclk1" };
+
+PNAME(dclk_s3c2443_p) = { "pclk", "epll" };
+PNAME(clkout0_s3c2443_p) = { "xti", "epll", "armclk", "hclk", "pclk",
+			     "gate_dclk0" };
+PNAME(clkout1_s3c2443_p) = { "dummy", "epll", "rtc_clkout",
+			     "hclk", "pclk", "gate_dclk1" };
+
+#define DCLKCON_DCLK_DIV_MASK		0xf
+#define DCLKCON_DCLK0_DIV_SHIFT		4
+#define DCLKCON_DCLK0_CMP_SHIFT		8
+#define DCLKCON_DCLK1_DIV_SHIFT		20
+#define DCLKCON_DCLK1_CMP_SHIFT		24
+
+static void s3c24xx_dclk_update_cmp(struct s3c24xx_dclk *s3c24xx_dclk,
+				    int div_shift, int cmp_shift)
+{
+	unsigned long flags = 0;
+	u32 dclk_con, div, cmp;
+
+	spin_lock_irqsave(&s3c24xx_dclk->dclk_lock, flags);
+
+	dclk_con = readl_relaxed(s3c24xx_dclk->base);
+
+	div = ((dclk_con >> div_shift) & DCLKCON_DCLK_DIV_MASK) + 1;
+	cmp = ((div + 1) / 2) - 1;
+
+	dclk_con &= ~(DCLKCON_DCLK_DIV_MASK << cmp_shift);
+	dclk_con |= (cmp << cmp_shift);
+
+	writel_relaxed(dclk_con, s3c24xx_dclk->base);
+
+	spin_unlock_irqrestore(&s3c24xx_dclk->dclk_lock, flags);
+}
+
+static int s3c24xx_dclk0_div_notify(struct notifier_block *nb,
+			       unsigned long event, void *data)
+{
+	struct s3c24xx_dclk *s3c24xx_dclk = to_s3c24xx_dclk0(nb);
+
+	if (event == POST_RATE_CHANGE) {
+		s3c24xx_dclk_update_cmp(s3c24xx_dclk,
+			DCLKCON_DCLK0_DIV_SHIFT, DCLKCON_DCLK0_CMP_SHIFT);
+	}
+
+	return NOTIFY_DONE;
+}
+
+static int s3c24xx_dclk1_div_notify(struct notifier_block *nb,
+			       unsigned long event, void *data)
+{
+	struct s3c24xx_dclk *s3c24xx_dclk = to_s3c24xx_dclk1(nb);
+
+	if (event == POST_RATE_CHANGE) {
+		s3c24xx_dclk_update_cmp(s3c24xx_dclk,
+			DCLKCON_DCLK1_DIV_SHIFT, DCLKCON_DCLK1_CMP_SHIFT);
+	}
+
+	return NOTIFY_DONE;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int s3c24xx_dclk_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct s3c24xx_dclk *s3c24xx_dclk = platform_get_drvdata(pdev);
+
+	s3c24xx_dclk->reg_save = readl_relaxed(s3c24xx_dclk->base);
+	return 0;
+}
+
+static int s3c24xx_dclk_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct s3c24xx_dclk *s3c24xx_dclk = platform_get_drvdata(pdev);
+
+	writel_relaxed(s3c24xx_dclk->reg_save, s3c24xx_dclk->base);
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(s3c24xx_dclk_pm_ops,
+			 s3c24xx_dclk_suspend, s3c24xx_dclk_resume);
+
+static int s3c24xx_dclk_probe(struct platform_device *pdev)
+{
+	struct s3c24xx_dclk *s3c24xx_dclk;
+	struct resource *mem;
+	struct clk **clk_table;
+	struct s3c24xx_dclk_drv_data *dclk_variant;
+	int ret, i;
+
+	s3c24xx_dclk = devm_kzalloc(&pdev->dev, sizeof(*s3c24xx_dclk),
+				    GFP_KERNEL);
+	if (!s3c24xx_dclk)
+		return -ENOMEM;
+
+	s3c24xx_dclk->dev = &pdev->dev;
+	platform_set_drvdata(pdev, s3c24xx_dclk);
+	spin_lock_init(&s3c24xx_dclk->dclk_lock);
+
+	clk_table = devm_kzalloc(&pdev->dev,
+				 sizeof(struct clk *) * DCLK_MAX_CLKS,
+				 GFP_KERNEL);
+	if (!clk_table)
+		return -ENOMEM;
+
+	s3c24xx_dclk->clk_data.clks = clk_table;
+	s3c24xx_dclk->clk_data.clk_num = DCLK_MAX_CLKS;
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	s3c24xx_dclk->base = devm_ioremap_resource(&pdev->dev, mem);
+	if (IS_ERR(s3c24xx_dclk->base))
+		return PTR_ERR(s3c24xx_dclk->base);
+
+	dclk_variant = (struct s3c24xx_dclk_drv_data *)
+				platform_get_device_id(pdev)->driver_data;
+
+
+	clk_table[MUX_DCLK0] = clk_register_mux(&pdev->dev, "mux_dclk0",
+				dclk_variant->mux_parent_names,
+				dclk_variant->mux_num_parents, 0,
+				s3c24xx_dclk->base, 1, 1, 0,
+				&s3c24xx_dclk->dclk_lock);
+	clk_table[MUX_DCLK1] = clk_register_mux(&pdev->dev, "mux_dclk1",
+				dclk_variant->mux_parent_names,
+				dclk_variant->mux_num_parents, 0,
+				s3c24xx_dclk->base, 17, 1, 0,
+				&s3c24xx_dclk->dclk_lock);
+
+	clk_table[DIV_DCLK0] = clk_register_divider(&pdev->dev, "div_dclk0",
+				"mux_dclk0", 0, s3c24xx_dclk->base,
+				4, 4, 0, &s3c24xx_dclk->dclk_lock);
+	clk_table[DIV_DCLK1] = clk_register_divider(&pdev->dev, "div_dclk1",
+				"mux_dclk1", 0, s3c24xx_dclk->base,
+				20, 4, 0, &s3c24xx_dclk->dclk_lock);
+
+	clk_table[GATE_DCLK0] = clk_register_gate(&pdev->dev, "gate_dclk0",
+				"div_dclk0", CLK_SET_RATE_PARENT,
+				s3c24xx_dclk->base, 0, 0,
+				&s3c24xx_dclk->dclk_lock);
+	clk_table[GATE_DCLK1] = clk_register_gate(&pdev->dev, "gate_dclk1",
+				"div_dclk1", CLK_SET_RATE_PARENT,
+				s3c24xx_dclk->base, 16, 0,
+				&s3c24xx_dclk->dclk_lock);
+
+	clk_table[MUX_CLKOUT0] = s3c24xx_register_clkout(&pdev->dev,
+				"clkout0", dclk_variant->clkout0_parent_names,
+				dclk_variant->clkout0_num_parents, 4, 7);
+	clk_table[MUX_CLKOUT1] = s3c24xx_register_clkout(&pdev->dev,
+				"clkout1", dclk_variant->clkout1_parent_names,
+				dclk_variant->clkout1_num_parents, 8, 7);
+
+	for (i = 0; i < DCLK_MAX_CLKS; i++)
+		if (IS_ERR(clk_table[i])) {
+			dev_err(&pdev->dev, "clock %d failed to register\n", i);
+			ret = PTR_ERR(clk_table[i]);
+			goto err_clk_register;
+		}
+
+	ret = clk_register_clkdev(clk_table[MUX_DCLK0], "dclk0", NULL);
+	if (!ret)
+		ret = clk_register_clkdev(clk_table[MUX_DCLK1], "dclk1", NULL);
+	if (!ret)
+		ret = clk_register_clkdev(clk_table[MUX_CLKOUT0],
+					  "clkout0", NULL);
+	if (!ret)
+		ret = clk_register_clkdev(clk_table[MUX_CLKOUT1],
+					  "clkout1", NULL);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to register aliases, %d\n", ret);
+		goto err_clk_register;
+	}
+
+	s3c24xx_dclk->dclk0_div_change_nb.notifier_call =
+						s3c24xx_dclk0_div_notify;
+
+	s3c24xx_dclk->dclk1_div_change_nb.notifier_call =
+						s3c24xx_dclk1_div_notify;
+
+	ret = clk_notifier_register(clk_table[DIV_DCLK0],
+				    &s3c24xx_dclk->dclk0_div_change_nb);
+	if (ret)
+		goto err_clk_register;
+
+	ret = clk_notifier_register(clk_table[DIV_DCLK1],
+				    &s3c24xx_dclk->dclk1_div_change_nb);
+	if (ret)
+		goto err_dclk_notify;
+
+	return 0;
+
+err_dclk_notify:
+	clk_notifier_unregister(clk_table[DIV_DCLK0],
+				&s3c24xx_dclk->dclk0_div_change_nb);
+err_clk_register:
+	for (i = 0; i < DCLK_MAX_CLKS; i++)
+		if (clk_table[i] && !IS_ERR(clk_table[i]))
+			clk_unregister(clk_table[i]);
+
+	return ret;
+}
+
+static int s3c24xx_dclk_remove(struct platform_device *pdev)
+{
+	struct s3c24xx_dclk *s3c24xx_dclk = platform_get_drvdata(pdev);
+	struct clk **clk_table = s3c24xx_dclk->clk_data.clks;
+	int i;
+
+	clk_notifier_unregister(clk_table[DIV_DCLK1],
+				&s3c24xx_dclk->dclk1_div_change_nb);
+	clk_notifier_unregister(clk_table[DIV_DCLK0],
+				&s3c24xx_dclk->dclk0_div_change_nb);
+
+	for (i = 0; i < DCLK_MAX_CLKS; i++)
+		clk_unregister(clk_table[i]);
+
+	return 0;
+}
+
+static struct s3c24xx_dclk_drv_data dclk_variants[] = {
+	[S3C2410] = {
+		.clkout0_parent_names = clkout0_s3c2410_p,
+		.clkout0_num_parents = ARRAY_SIZE(clkout0_s3c2410_p),
+		.clkout1_parent_names = clkout1_s3c2410_p,
+		.clkout1_num_parents = ARRAY_SIZE(clkout1_s3c2410_p),
+		.mux_parent_names = dclk_s3c2410_p,
+		.mux_num_parents = ARRAY_SIZE(dclk_s3c2410_p),
+	},
+	[S3C2412] = {
+		.clkout0_parent_names = clkout0_s3c2412_p,
+		.clkout0_num_parents = ARRAY_SIZE(clkout0_s3c2412_p),
+		.clkout1_parent_names = clkout1_s3c2412_p,
+		.clkout1_num_parents = ARRAY_SIZE(clkout1_s3c2412_p),
+		.mux_parent_names = dclk_s3c2410_p,
+		.mux_num_parents = ARRAY_SIZE(dclk_s3c2410_p),
+	},
+	[S3C2440] = {
+		.clkout0_parent_names = clkout0_s3c2440_p,
+		.clkout0_num_parents = ARRAY_SIZE(clkout0_s3c2440_p),
+		.clkout1_parent_names = clkout1_s3c2440_p,
+		.clkout1_num_parents = ARRAY_SIZE(clkout1_s3c2440_p),
+		.mux_parent_names = dclk_s3c2410_p,
+		.mux_num_parents = ARRAY_SIZE(dclk_s3c2410_p),
+	},
+	[S3C2443] = {
+		.clkout0_parent_names = clkout0_s3c2443_p,
+		.clkout0_num_parents = ARRAY_SIZE(clkout0_s3c2443_p),
+		.clkout1_parent_names = clkout1_s3c2443_p,
+		.clkout1_num_parents = ARRAY_SIZE(clkout1_s3c2443_p),
+		.mux_parent_names = dclk_s3c2443_p,
+		.mux_num_parents = ARRAY_SIZE(dclk_s3c2443_p),
+	},
+};
+
+static struct platform_device_id s3c24xx_dclk_driver_ids[] = {
+	{
+		.name		= "s3c2410-dclk",
+		.driver_data	= (kernel_ulong_t)&dclk_variants[S3C2410],
+	}, {
+		.name		= "s3c2412-dclk",
+		.driver_data	= (kernel_ulong_t)&dclk_variants[S3C2412],
+	}, {
+		.name		= "s3c2440-dclk",
+		.driver_data	= (kernel_ulong_t)&dclk_variants[S3C2440],
+	}, {
+		.name		= "s3c2443-dclk",
+		.driver_data	= (kernel_ulong_t)&dclk_variants[S3C2443],
+	},
+	{ }
+};
+
+MODULE_DEVICE_TABLE(platform, s3c24xx_dclk_driver_ids);
+
+static struct platform_driver s3c24xx_dclk_driver = {
+	.driver = {
+		.name		= "s3c24xx-dclk",
+		.owner		= THIS_MODULE,
+		.pm		= &s3c24xx_dclk_pm_ops,
+	},
+	.probe = s3c24xx_dclk_probe,
+	.remove = s3c24xx_dclk_remove,
+	.id_table = s3c24xx_dclk_driver_ids,
+};
+module_platform_driver(s3c24xx_dclk_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
+MODULE_DESCRIPTION("Driver for the S3C24XX external clock outputs");