[PATCH 2/5] regulator: st-flashss: Add a regulator driver for flashss vsense.

[Peter Griffin]

This patch adds a small regulator driver to manage the voltage regulator
inside the ST flash subsystem found on stih407 based silicon, and is
used for configuring the eMMC, NAND and SPI voltages.

Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@xxxxxx>
Signed-off-by: Peter Griffin <peter.griffin@xxxxxxxxxx>
---
 drivers/regulator/Kconfig      |   7 ++
 drivers/regulator/Makefile     |   2 +-
 drivers/regulator/st-flashss.c | 274 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 282 insertions(+), 1 deletion(-)
 create mode 100644 drivers/regulator/st-flashss.c

diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index c77dc08..ddf2bcd 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -843,5 +843,12 @@ config REGULATOR_WM8994
 	  This driver provides support for the voltage regulators on the
 	  WM8994 CODEC.
 
+config REGULATOR_ST_FLASHSS
+	tristate "STMicroelectronics FlashSS regulator"
+	depends on ARCH_STI && OF
+	help
+	  This driver provides support for the voltage regulators available
+	  inside the FlashSS of STiH407/STiH410 SoC's.
+
 endif
 
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index 61bfbb9..10be29b 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -108,6 +108,6 @@ obj-$(CONFIG_REGULATOR_WM831X) += wm831x-ldo.o
 obj-$(CONFIG_REGULATOR_WM8350) += wm8350-regulator.o
 obj-$(CONFIG_REGULATOR_WM8400) += wm8400-regulator.o
 obj-$(CONFIG_REGULATOR_WM8994) += wm8994-regulator.o
-
+obj-$(CONFIG_REGULATOR_ST_FLASHSS) += st-flashss.o
 
 ccflags-$(CONFIG_REGULATOR_DEBUG) += -DDEBUG
diff --git a/drivers/regulator/st-flashss.c b/drivers/regulator/st-flashss.c
new file mode 100644
index 0000000..9c0e011
--- /dev/null
+++ b/drivers/regulator/st-flashss.c
@@ -0,0 +1,274 @@
+/*
+ * ST regulator driver for flashSS vsense
+ *
+ * This is a small driver to manage the voltage regulator inside the ST flash
+ * sub-system that is used for configuring MMC, NAND, SPI voltages.
+ *
+ * Copyright(C) 2015 STMicroelectronics Ltd
+ * Author: Giuseppe Cavallaro <peppe.cavallaro@xxxxxx>
+ *
+ * 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.
+ */
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/regulator/of_regulator.h>
+
+/* FlashSS voltage VSENSE TOP CONFIG register defines */
+#define TOP_VSENSE_CONFIG_REG_PSW_EMMC		BIT(0)
+#define TOP_VSENSE_CONFIG_ENB_REG_PSW_EMMC	BIT(1)
+#define TOP_VSENSE_CONFIG_REG_PSW_NAND		BIT(8)
+#define TOP_VSENSE_CONFIG_ENB_REG_PSW_NAND	BIT(9)
+#define TOP_VSENSE_CONFIG_REG_PSW_SPI		BIT(16)
+#define TOP_VSENSE_CONFIG_ENB_REG_PSW_SPI	BIT(17)
+#define TOP_VSENSE_CONFIG_LATCHED_PSW_EMMC	BIT(24)
+#define TOP_VSENSE_CONFIG_LATCHED_PSW_NAND	BIT(25)
+#define TOP_VSENSE_CONFIG_LATCHED_PSW_SPI	BIT(26)
+
+struct st_vsense {
+	char *name;
+	struct device *dev;
+	u8 n_voltages;			/* number of supported voltages */
+	void __iomem *ioaddr;		/* TOP config base address */
+	unsigned int en_psw_mask;	/* Mask/enable vdd for each device */
+	unsigned int psw_mask;		/* Power sel mask for VDD */
+	unsigned int latched_mask;	/* Latched mask for VDD */
+};
+
+static const unsigned int st_type_voltages[] = {
+	1800000,
+	3300000,
+};
+
+const struct st_vsense st_vsense_data[] = {
+	{
+		.en_psw_mask = TOP_VSENSE_CONFIG_ENB_REG_PSW_EMMC,
+		.psw_mask = TOP_VSENSE_CONFIG_REG_PSW_EMMC,
+		.latched_mask = TOP_VSENSE_CONFIG_LATCHED_PSW_EMMC,
+	}, {
+		.en_psw_mask = TOP_VSENSE_CONFIG_ENB_REG_PSW_NAND,
+		.psw_mask = TOP_VSENSE_CONFIG_REG_PSW_NAND,
+		.latched_mask = TOP_VSENSE_CONFIG_LATCHED_PSW_NAND,
+	}, {
+		.en_psw_mask = TOP_VSENSE_CONFIG_ENB_REG_PSW_SPI,
+		.psw_mask = TOP_VSENSE_CONFIG_REG_PSW_SPI,
+		.latched_mask = TOP_VSENSE_CONFIG_LATCHED_PSW_SPI,
+	},
+};
+
+/* Get the value of Sensed-PSW of eMMC/NAND/SPI Pads */
+static int st_get_voltage_sel(struct regulator_dev *dev)
+{
+	struct st_vsense *vsense = rdev_get_drvdata(dev);
+	void __iomem *ioaddr = vsense->ioaddr;
+	int sel = 0;
+	u32 value = readl_relaxed(ioaddr);
+
+	if (value & vsense->latched_mask)
+		sel = 1;
+
+	dev_dbg(vsense->dev, "%s, selection %d (0x%08x)\n", vsense->name, sel,
+		readl_relaxed(ioaddr));
+
+	return sel;
+}
+
+static int st_set_voltage_sel(struct regulator_dev *dev, unsigned int selector)
+{
+	struct st_vsense *vsense = rdev_get_drvdata(dev);
+	void __iomem *ioaddr = vsense->ioaddr;
+	unsigned int value = readl_relaxed(ioaddr);
+	unsigned int voltage;
+
+	voltage = st_type_voltages[selector];
+
+	value |= vsense->en_psw_mask;
+	if (voltage == 3300000)
+		value |= vsense->psw_mask;
+	else
+		value &= ~vsense->psw_mask;
+
+	writel_relaxed(value, ioaddr);
+
+	dev_dbg(vsense->dev, "%s, required voltage %d (vsense_conf 0x%08x)\n",
+		vsense->name, voltage,
+		readl_relaxed(ioaddr));
+
+	return 0;
+}
+
+static struct regulator_ops st_ops = {
+	.get_voltage_sel = st_get_voltage_sel,
+	.set_voltage_sel = st_set_voltage_sel,
+	.list_voltage = regulator_list_voltage_table,
+};
+
+static const struct of_device_id of_st_match_tbl[] = {
+	{.compatible = "st,vqmmc", .data = &st_vsense_data[0]},
+	{.compatible = "st,vnand", .data = &st_vsense_data[1]},
+	{.compatible = "st,vspi", .data = &st_vsense_data[2]},
+	{ /* end */ }
+};
+
+static void st_get_satinize_powerup_voltage(struct st_vsense *vsense)
+{
+	void __iomem *ioaddr = vsense->ioaddr;
+	u32 value = readl_relaxed(ioaddr);
+
+	dev_dbg(vsense->dev, "Initial start-up value: (0x%08x)\n", value);
+
+	/* Sanitize voltage values forcing what is provided from start-up */
+	if (value & TOP_VSENSE_CONFIG_LATCHED_PSW_EMMC)
+		value |= TOP_VSENSE_CONFIG_REG_PSW_EMMC;
+	else
+		value &= ~TOP_VSENSE_CONFIG_REG_PSW_EMMC;
+
+	if (value & TOP_VSENSE_CONFIG_LATCHED_PSW_NAND)
+		value |= TOP_VSENSE_CONFIG_REG_PSW_NAND;
+	else
+		value &= ~TOP_VSENSE_CONFIG_REG_PSW_NAND;
+
+	if (value & TOP_VSENSE_CONFIG_LATCHED_PSW_SPI)
+		value |= TOP_VSENSE_CONFIG_REG_PSW_SPI;
+	else
+		value &= ~TOP_VSENSE_CONFIG_REG_PSW_SPI;
+
+	writel_relaxed(value, ioaddr);
+
+	dev_dbg(vsense->dev, "Sanitized value: (0x%08x)\n", value);
+}
+
+static int st_vsense_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct st_vsense *vsense;
+	const struct of_device_id *device;
+	struct resource *res;
+	struct regulator_desc *rdesc;
+	struct regulator_dev *rdev;
+	struct regulator_config config = { };
+
+	vsense = devm_kzalloc(dev, sizeof(*vsense), GFP_KERNEL);
+	if (!vsense)
+		return -ENOMEM;
+
+	vsense->dev = dev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	vsense->ioaddr = devm_ioremap_resource(dev, res);
+	if (IS_ERR(vsense->ioaddr))
+		return PTR_ERR(vsense->ioaddr);
+
+	rdesc = devm_kzalloc(dev, sizeof(*rdesc), GFP_KERNEL);
+	if (!rdesc)
+		return -ENOMEM;
+
+	device = of_match_device(of_st_match_tbl, &pdev->dev);
+	if (!device)
+		return -ENODEV;
+
+	if (device->data) {
+		const struct st_vsense *data = device->data;
+
+		vsense->en_psw_mask = data->en_psw_mask;
+		vsense->psw_mask = data->psw_mask;
+		vsense->latched_mask = data->latched_mask;
+	} else
+		return -ENODEV;
+
+	if (of_property_read_string(np, "regulator-name",
+				    (const char **)&vsense->name))
+		return -EINVAL;
+
+	memset(rdesc, 0, sizeof(*rdesc));
+	rdesc->name = vsense->name;
+	rdesc->ops = &st_ops;
+	rdesc->type = REGULATOR_VOLTAGE;
+	rdesc->owner = THIS_MODULE;
+	rdesc->n_voltages = ARRAY_SIZE(st_type_voltages);
+	rdesc->volt_table = st_type_voltages;
+	config.dev = &pdev->dev;
+	config.driver_data = vsense;
+	config.of_node = np;
+
+	config.init_data = of_get_regulator_init_data(&pdev->dev, np, rdesc);
+	if (!config.init_data) {
+		dev_err(dev, "Failed to parse regulator init data\n");
+		return -ENOMEM;
+	}
+
+	/* register regulator */
+	rdev = regulator_register(rdesc, &config);
+	if (IS_ERR(rdev)) {
+		dev_err(dev, "failed to register %s\n", rdesc->name);
+		return PTR_ERR(rdev);
+	}
+
+	platform_set_drvdata(pdev, rdev);
+
+	dev_info(dev, "%s  vsense voltage regulator registered\n", rdesc->name);
+	st_get_satinize_powerup_voltage(vsense);
+
+	return 0;
+}
+
+static int st_vsense_remove(struct platform_device *pdev)
+{
+	struct regulator_dev *rdev = platform_get_drvdata(pdev);
+
+	regulator_unregister(rdev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int st_vsense_resume(struct device *dev)
+{
+	struct regulator_dev *rdev = dev_get_drvdata(dev);
+	struct st_vsense *vsense = rdev_get_drvdata(rdev);
+
+	st_get_satinize_powerup_voltage(vsense);
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops st_vsense_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(NULL, st_vsense_resume)
+};
+
+static struct platform_driver st_vsense_driver = {
+	.driver = {
+		   .name = "st-vsense",
+		   .of_match_table = of_st_match_tbl,
+		   .pm	= &st_vsense_pm_ops,
+		   },
+	.probe = st_vsense_probe,
+	.remove = st_vsense_remove,
+};
+
+static int __init st_vsense_init(void)
+{
+	return platform_driver_register(&st_vsense_driver);
+}
+
+subsys_initcall(st_vsense_init);
+
+static void __exit st_vsense_cleanup(void)
+{
+	platform_driver_unregister(&st_vsense_driver);
+}
+
+module_exit(st_vsense_cleanup);
+
+MODULE_AUTHOR("Giuseppe Cavallaro <peppe.cavallaro@xxxxxx>");
+MODULE_DESCRIPTION("ST voltage regulator driver for vsense flashSS");
+MODULE_LICENSE("GPL v2");
-- 
1.9.1