[3/4] clk: 88pm800: Add clk provider driver for 88pm800 family of devices

diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 42f7120..c34c14d 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -167,6 +167,14 @@  config COMMON_CLK_CDCE706
 	---help---
 	  This driver supports TI CDCE706 programmable 3-PLL clock synthesizer.
 
+config COMMON_CLK_88PM800
+	tristate "Clock driver for 88PM800 MFD"
+	depends on MFD_88PM800
+	---help---
+	  This driver supports 88PM800 & 88PM860 crystal oscillator
+	  clock. These multi-function devices have two (88PM860) or three
+	  (88PM800) fixed-rate output, clocked at 32KHz each.
+
 source "drivers/clk/bcm/Kconfig"
 source "drivers/clk/hisilicon/Kconfig"
 source "drivers/clk/qcom/Kconfig"
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index c4cf075..5248cd3 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -80,3 +80,4 @@  obj-$(CONFIG_X86)			+= x86/
 obj-$(CONFIG_ARCH_ZX)			+= zte/
 obj-$(CONFIG_ARCH_ZYNQ)			+= zynq/
 obj-$(CONFIG_H8300)		+= h8300/
+obj-$(CONFIG_COMMON_CLK_88PM800)	+= clk-88pm800.o
diff --git a/drivers/clk/clk-88pm800.c b/drivers/clk/clk-88pm800.c
new file mode 100644
index 0000000..cf1c162
--- /dev/null
+++ b/drivers/clk/clk-88pm800.c
@@ -0,0 +1,345 @@ 
+/*
+ * clk-88pm800.c - Clock driver for 88PM800 family of devices
+ *
+ * This driver is created based on clk-s2mps11.c
+ *
+ * Copyright (C) 2015 Linaro Ltd.
+ *
+ * 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/module.h>
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/clkdev.h>
+#include <linux/regmap.h>
+#include <linux/clk-provider.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/88pm80x.h>
+
+/* Number of clocks output from 88pm800 family of device */
+enum {
+	PM800_CLK32K_1 = 0,
+	PM800_CLK32K_2,
+	PM800_CLK32K_3,
+	PM800_CLKS_NUM,
+};
+
+struct pm800_clk {
+	struct pm80x_chip *chip;
+	struct device_node *clk_np;
+	struct clk_hw hw;
+	struct clk *clk;
+	struct clk_lookup *lookup;
+	u32 mask;
+	u32 shift;
+	unsigned int reg;
+};
+
+static struct pm800_clk *to_pm800_clk(struct clk_hw *hw)
+{
+	return container_of(hw, struct pm800_clk, hw);
+}
+
+static int pm800_clk_prepare(struct clk_hw *hw)
+{
+	struct pm800_clk *pm800 = to_pm800_clk(hw);
+	int ret;
+
+	/* We always want to use XO clock */
+	ret = regmap_update_bits(pm800->chip->regmap,
+				 pm800->reg,
+				 pm800->mask,
+				 PM800_32K_OUTX_SEL_XO_32KHZ << pm800->shift);
+
+	return ret;
+}
+
+static void pm800_clk_unprepare(struct clk_hw *hw)
+{
+	struct pm800_clk *pm800 = to_pm800_clk(hw);
+	int ret;
+
+	ret = regmap_update_bits(pm800->chip->regmap, pm800->reg,
+				pm800->mask, ~pm800->mask);
+}
+
+static int pm800_clk_is_prepared(struct clk_hw *hw)
+{
+	int ret;
+	u32 val;
+	struct pm800_clk *pm800 = to_pm800_clk(hw);
+
+	ret = regmap_read(pm800->chip->regmap,
+				pm800->reg, &val);
+	if (ret < 0)
+		return -EINVAL;
+
+	return ((val & pm800->mask) >> pm800->shift);
+}
+
+static unsigned long pm800_clk_recalc_rate(struct clk_hw *hw,
+					     unsigned long parent_rate)
+{
+	return 32768;
+}
+
+static struct clk_ops pm800_clk_ops = {
+	.prepare	= pm800_clk_prepare,
+	.unprepare	= pm800_clk_unprepare,
+	.is_prepared	= pm800_clk_is_prepared,
+	.recalc_rate	= pm800_clk_recalc_rate,
+};
+
+static struct clk_init_data pm800_clks_init[PM800_CLKS_NUM] = {
+	[PM800_CLK32K_1] = {
+		.name	= "pm800_clk32k_1",
+		.ops	= &pm800_clk_ops,
+		.flags	= CLK_IS_ROOT,
+	},
+	[PM800_CLK32K_2] = {
+		.name	= "pm800_clk32k_2",
+		.ops	= &pm800_clk_ops,
+		.flags	= CLK_IS_ROOT,
+	},
+	[PM800_CLK32K_3] = {
+		.name	= "pm800_clk32k_3",
+		.ops	= &pm800_clk_ops,
+		.flags	= CLK_IS_ROOT,
+	},
+};
+
+static struct clk_init_data pm860_clks_init[PM800_CLKS_NUM] = {
+	[PM800_CLK32K_1] = {
+		.name	= "pm800_clk32k_1",
+		.ops	= &pm800_clk_ops,
+		.flags	= CLK_IS_ROOT,
+	},
+	[PM800_CLK32K_2] = {
+		.name	= "pm800_clk32k_2",
+		.ops	= &pm800_clk_ops,
+		.flags	= CLK_IS_ROOT,
+	},
+};
+
+static int pm800_init_clk(struct pm800_clk *pm800_clks)
+{
+
+	int ret;
+
+	/* Enable XO_LJ : Low jitter clock of 32KHz from XO */
+	ret = regmap_update_bits(pm800_clks->chip->regmap, PM800_LOW_POWER2,
+			PM800_LOW_POWER2_XO_LJ_EN, PM800_LOW_POWER2_XO_LJ_EN);
+	if (ret)
+		return ret;
+
+	/* Enable USE_XO : Use XO clock for all internal timing reference */
+	ret = regmap_update_bits(pm800_clks->chip->regmap, PM800_RTC_CONTROL,
+			PM800_RTC1_USE_XO, PM800_RTC1_USE_XO);
+	if (ret)
+		return ret;
+
+	/* OSC_FREERUN: Enable Osc free running mode by clearing the bit */
+	ret = regmap_update_bits(pm800_clks->chip->regmap, PM800_OSC_CNTRL1,
+			PM800_OSC_CNTRL1_OSC_FREERUN_EN, 0);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static struct device_node *pm800_clk_parse_dt(struct platform_device *pdev,
+		struct clk_init_data *clks_init)
+{
+	struct pm80x_chip *chip = dev_get_drvdata(pdev->dev.parent);
+	struct device_node *clk_np;
+	int i;
+
+	if (!chip->dev->of_node)
+		return ERR_PTR(-EINVAL);
+
+	clk_np = of_get_child_by_name(chip->dev->of_node, "clocks");
+	if (!clk_np) {
+		dev_err(&pdev->dev, "could not find clock sub-node\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	for (i = 0; i < PM800_CLKS_NUM; i++) {
+		if (!clks_init[i].name)
+			continue; /* Skip clocks not present in some devices */
+
+		of_property_read_string_index(clk_np, "clock-output-names", i,
+				&clks_init[i].name);
+	}
+
+	return clk_np;
+}
+
+static int pm800_clk_probe(struct platform_device *pdev)
+{
+	struct pm80x_chip *chip = dev_get_drvdata(pdev->dev.parent);
+	struct pm800_clk *pm800_clks;
+	struct clk_init_data *clks_init;
+	static struct clk **clk_table;
+	static struct clk_onecell_data *of_clk_data;
+	int i, ret = 0;
+
+	pm800_clks = devm_kzalloc(&pdev->dev,
+				sizeof(*pm800_clks) * PM800_CLKS_NUM,
+				GFP_KERNEL);
+	if (!pm800_clks)
+		return -ENOMEM;
+
+	clk_table = devm_kzalloc(&pdev->dev,
+				sizeof(struct clk *) * PM800_CLKS_NUM,
+				GFP_KERNEL);
+	if (!clk_table)
+		return -ENOMEM;
+
+	switch (platform_get_device_id(pdev)->driver_data) {
+	case CHIP_PM800:
+		clks_init = pm800_clks_init;
+		break;
+	case CHIP_PM860:
+		clks_init = pm860_clks_init;
+		break;
+	default:
+		dev_err(&pdev->dev, "Invalid device type\n");
+		return -EINVAL;
+	}
+
+	/* Store clocks of_node in first element of pm800_clks array */
+	pm800_clks->clk_np = pm800_clk_parse_dt(pdev, clks_init);
+	if (IS_ERR(pm800_clks->clk_np))
+		return PTR_ERR(pm800_clks->clk_np);
+
+	of_clk_data = devm_kzalloc(&pdev->dev,
+				sizeof(*of_clk_data),
+				GFP_KERNEL);
+	if (!of_clk_data)
+		return -ENOMEM;
+
+	for (i = 0; i < PM800_CLKS_NUM; i++) {
+		if (!clks_init[i].name)
+			continue; /* Skip clocks not present in some devices */
+
+		pm800_clks[i].chip = chip;
+		pm800_clks[i].hw.init = &clks_init[i];
+		/*
+		 * As of now, mask and shift formula below works for both
+		 * 88PM800 and it's family of devices,
+		 *
+		 *  PM800_RTC_MISC2:
+		 *      1:0	= CK_32K_OUT1_SEL
+		 *      3:2	= CK_32K_OUT2_SEL
+		 *      5:4	= CK_32K_OUT3_SEL
+		 */
+		pm800_clks[i].shift = (i * 2);
+		pm800_clks[i].mask = PM800_32K_OUTX_SEL_MASK << pm800_clks[i].shift;
+		pm800_clks[i].reg = PM800_RTC_MISC2;
+
+		pm800_clks[i].clk = devm_clk_register(&pdev->dev,
+							&pm800_clks[i].hw);
+		if (IS_ERR(pm800_clks[i].clk)) {
+			dev_err(&pdev->dev, "Fail to register : %s\n",
+						clks_init[i].name);
+			ret = PTR_ERR(pm800_clks[i].clk);
+			goto err;
+		}
+
+		pm800_clks[i].lookup = clkdev_create(pm800_clks[i].clk,
+					clks_init[i].name, NULL);
+		if (!pm800_clks[i].lookup) {
+			ret = -ENOMEM;
+			goto err;
+		}
+
+		clk_table[i] = pm800_clks[i].clk;
+	}
+
+	of_clk_data->clks = clk_table;
+	of_clk_data->clk_num = PM800_CLKS_NUM;
+	ret = of_clk_add_provider(pm800_clks->clk_np, of_clk_src_onecell_get,
+			of_clk_data);
+	if (ret) {
+		dev_err(&pdev->dev, "Fail to add OF clk provider : %d\n", ret);
+		goto err;
+	}
+
+	/* Common for all 32KHz clock output */
+	ret = pm800_init_clk(&pm800_clks[0]);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to initialize clk : %d\n", ret);
+		goto err;
+	}
+
+	platform_set_drvdata(pdev, pm800_clks);
+
+	return 0;
+
+err:
+	for (i = 0; i < PM800_CLKS_NUM; i++) {
+		if (pm800_clks[i].lookup)
+			clkdev_drop(pm800_clks[i].lookup);
+	}
+
+	return ret;
+}
+
+static int pm800_clk_remove(struct platform_device *pdev)
+{
+	struct pm800_clk *pm800_clks = platform_get_drvdata(pdev);
+	int i;
+
+	of_clk_del_provider(pm800_clks[0].clk_np);
+	/* Drop the reference obtained in pm800_clk_parse_dt */
+	of_node_put(pm800_clks[0].clk_np);
+
+	for (i = 0; i < PM800_CLKS_NUM; i++) {
+		if (pm800_clks[i].lookup)
+			clkdev_drop(pm800_clks[i].lookup);
+	}
+
+	return 0;
+}
+
+static const struct platform_device_id pm800_clk_id[] = {
+	{ "88pm800-clk", CHIP_PM800},
+	{ "88pm860-clk", CHIP_PM860},
+	{ },
+};
+MODULE_DEVICE_TABLE(platform, pm800_clk_id);
+
+static struct platform_driver pm800_clk_driver = {
+	.driver = {
+		.name  = "88pm80x-clk",
+	},
+	.probe = pm800_clk_probe,
+	.remove = pm800_clk_remove,
+	.id_table = pm800_clk_id,
+};
+
+static int __init pm800_clk_init(void)
+{
+	return platform_driver_register(&pm800_clk_driver);
+}
+subsys_initcall(pm800_clk_init);
+
+static void __init pm800_clk_cleanup(void)
+{
+	platform_driver_unregister(&pm800_clk_driver);
+}
+module_exit(pm800_clk_cleanup);
+
+MODULE_DESCRIPTION("88PM800 Clock Driver");
+MODULE_AUTHOR("Vaibhav Hiremath <vaibhav.hiremath@linaro.org>");
+MODULE_LICENSE("GPL");