regulator: add pbias regulator support

pbias register controls internal power supply to sd card i/o pads
in most OMAPs (OMAP2-5, DRA7).
Control bits for selecting voltage level and
enabling/disabling are in the same PBIAS register.

Signed-off-by: Balaji T K <balajitk@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Mark Brown <broonie@linaro.org>
Tested-by: Florian Vaussard <florian.vaussard@epfl.ch>
Tested-by: Stefan Roese <sr@denx.de>
Signed-off-by: Chris Ball <chris@printf.net>

3 files changed, 265 insertions, 0 deletions

diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index 6a7932822e37..58f08d1d24e8 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -384,6 +384,15 @@ config REGULATOR_PALMAS
           on the muxing. This is handled automatically in the driver by
           reading the mux info from OTP.
 
+config REGULATOR_PBIAS
+        tristate "PBIAS OMAP regulator driver"
+        depends on (ARCH_OMAP || COMPILE_TEST) && MFD_SYSCON
+        help
+         Say y here to support pbias regulator for mmc1:SD card i/o
+         on OMAP SoCs.
+         This driver provides support for OMAP pbias modelled
+         regulators.
+
 config REGULATOR_PCAP
         tristate "Motorola PCAP2 regulator driver"
         depends on EZX_PCAP
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index 979f9ddcf259..001712ebbf25 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -54,6 +54,7 @@ obj-$(CONFIG_REGULATOR_MC13XXX_CORE) +=  mc13xxx-regulator-core.o
 obj-$(CONFIG_REGULATOR_PALMAS) += palmas-regulator.o
 obj-$(CONFIG_REGULATOR_PFUZE100) += pfuze100-regulator.o
 obj-$(CONFIG_REGULATOR_TPS51632) += tps51632-regulator.o
+obj-$(CONFIG_REGULATOR_PBIAS) += pbias-regulator.o
 obj-$(CONFIG_REGULATOR_PCAP) += pcap-regulator.o
 obj-$(CONFIG_REGULATOR_PCF50633) += pcf50633-regulator.o
 obj-$(CONFIG_REGULATOR_RC5T583)  += rc5t583-regulator.o
diff --git a/drivers/regulator/pbias-regulator.c b/drivers/regulator/pbias-regulator.c
new file mode 100644
index 000000000000..ded3b3574209
--- /dev/null
+++ b/drivers/regulator/pbias-regulator.c
@@ -0,0 +1,255 @@
+/*
+ * pbias-regulator.c
+ *
+ * Copyright (C) 2014 Texas Instruments Incorporated - http://www.ti.com/
+ * Author: Balaji T K <balajitk@ti.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 version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/mfd/syscon.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/regulator/of_regulator.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+
+struct pbias_reg_info {
+        u32 enable;
+        u32 enable_mask;
+        u32 vmode;
+        unsigned int enable_time;
+        char *name;
+};
+
+struct pbias_regulator_data {
+        struct regulator_desc desc;
+        void __iomem *pbias_addr;
+        unsigned int pbias_reg;
+        struct regulator_dev *dev;
+        struct regmap *syscon;
+        const struct pbias_reg_info *info;
+        int voltage;
+};
+
+static int pbias_regulator_set_voltage(struct regulator_dev *dev,
+                        int min_uV, int max_uV, unsigned *selector)
+{
+        struct pbias_regulator_data *data = rdev_get_drvdata(dev);
+        const struct pbias_reg_info *info = data->info;
+        int ret, vmode;
+
+        if (min_uV <= 1800000)
+                vmode = 0;
+        else if (min_uV > 1800000)
+                vmode = info->vmode;
+
+        ret = regmap_update_bits(data->syscon, data->pbias_reg,
+                                                info->vmode, vmode);
+
+        return ret;
+}
+
+static int pbias_regulator_get_voltage(struct regulator_dev *rdev)
+{
+        struct pbias_regulator_data *data = rdev_get_drvdata(rdev);
+        const struct pbias_reg_info *info = data->info;
+        int value, voltage;
+
+        regmap_read(data->syscon, data->pbias_reg, &value);
+        value &= info->vmode;
+
+        voltage = value ? 3000000 : 1800000;
+
+        return voltage;
+}
+
+static int pbias_regulator_enable(struct regulator_dev *rdev)
+{
+        struct pbias_regulator_data *data = rdev_get_drvdata(rdev);
+        const struct pbias_reg_info *info = data->info;
+        int ret;
+
+        ret = regmap_update_bits(data->syscon, data->pbias_reg,
+                                        info->enable_mask, info->enable);
+
+        return ret;
+}
+
+static int pbias_regulator_disable(struct regulator_dev *rdev)
+{
+        struct pbias_regulator_data *data = rdev_get_drvdata(rdev);
+        const struct pbias_reg_info *info = data->info;
+        int ret;
+
+        ret = regmap_update_bits(data->syscon, data->pbias_reg,
+                                                info->enable_mask, 0);
+        return ret;
+}
+
+static int pbias_regulator_is_enable(struct regulator_dev *rdev)
+{
+        struct pbias_regulator_data *data = rdev_get_drvdata(rdev);
+        const struct pbias_reg_info *info = data->info;
+        int value;
+
+        regmap_read(data->syscon, data->pbias_reg, &value);
+
+        return (value & info->enable_mask) == info->enable_mask;
+}
+
+static struct regulator_ops pbias_regulator_voltage_ops = {
+        .set_voltage    = pbias_regulator_set_voltage,
+        .get_voltage    = pbias_regulator_get_voltage,
+        .enable         = pbias_regulator_enable,
+        .disable        = pbias_regulator_disable,
+        .is_enabled     = pbias_regulator_is_enable,
+};
+
+static const struct pbias_reg_info pbias_mmc_omap2430 = {
+        .enable = BIT(1),
+        .enable_mask = BIT(1),
+        .vmode = BIT(0),
+        .enable_time = 100,
+        .name = "pbias_mmc_omap2430"
+};
+
+static const struct pbias_reg_info pbias_sim_omap3 = {
+        .enable = BIT(9),
+        .enable_mask = BIT(9),
+        .vmode = BIT(8),
+        .enable_time = 100,
+        .name = "pbias_sim_omap3"
+};
+
+static const struct pbias_reg_info pbias_mmc_omap4 = {
+        .enable = BIT(26) | BIT(22),
+        .enable_mask = BIT(26) | BIT(25) | BIT(22),
+        .vmode = BIT(21),
+        .enable_time = 100,
+        .name = "pbias_mmc_omap4"
+};
+
+static const struct pbias_reg_info pbias_mmc_omap5 = {
+        .enable = BIT(27) | BIT(26),
+        .enable_mask = BIT(27) | BIT(25) | BIT(26),
+        .vmode = BIT(21),
+        .enable_time = 100,
+        .name = "pbias_mmc_omap5"
+};
+
+static struct of_regulator_match pbias_matches[] = {
+        { .name = "pbias_mmc_omap2430", .driver_data = (void *)&pbias_mmc_omap2430},
+        { .name = "pbias_sim_omap3", .driver_data = (void *)&pbias_sim_omap3},
+        { .name = "pbias_mmc_omap4", .driver_data = (void *)&pbias_mmc_omap4},
+        { .name = "pbias_mmc_omap5", .driver_data = (void *)&pbias_mmc_omap5},
+};
+#define PBIAS_NUM_REGS  ARRAY_SIZE(pbias_matches)
+
+static const struct of_device_id pbias_of_match[] = {
+        { .compatible = "ti,pbias-omap", },
+        {},
+};
+MODULE_DEVICE_TABLE(of, pbias_of_match);
+
+static int pbias_regulator_probe(struct platform_device *pdev)
+{
+        struct device_node *np = pdev->dev.of_node;
+        struct pbias_regulator_data *drvdata;
+        struct resource *res;
+        struct regulator_config cfg = { };
+        struct regmap *syscon;
+        const struct pbias_reg_info *info;
+        int ret = 0;
+        int count, idx, data_idx = 0;
+
+        count = of_regulator_match(&pdev->dev, np, pbias_matches,
+                                                PBIAS_NUM_REGS);
+        if (count < 0)
+                return count;
+
+        drvdata = devm_kzalloc(&pdev->dev, sizeof(struct pbias_regulator_data)
+                               * count, GFP_KERNEL);
+        if (drvdata == NULL) {
+                dev_err(&pdev->dev, "Failed to allocate device data\n");
+                return -ENOMEM;
+        }
+
+        syscon = syscon_regmap_lookup_by_phandle(np, "syscon");
+        if (IS_ERR(syscon))
+                return PTR_ERR(syscon);
+
+        cfg.dev = &pdev->dev;
+
+        for (idx = 0; idx < PBIAS_NUM_REGS && data_idx < count; idx++) {
+                if (!pbias_matches[idx].init_data ||
+                        !pbias_matches[idx].of_node)
+                        continue;
+
+                info = pbias_matches[idx].driver_data;
+                if (!info)
+                        return -ENODEV;
+
+                res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+                if (!res)
+                        return -EINVAL;
+
+                drvdata[data_idx].pbias_reg = res->start;
+                drvdata[data_idx].syscon = syscon;
+                drvdata[data_idx].info = info;
+                drvdata[data_idx].desc.name = info->name;
+                drvdata[data_idx].desc.owner = THIS_MODULE;
+                drvdata[data_idx].desc.type = REGULATOR_VOLTAGE;
+                drvdata[data_idx].desc.ops = &pbias_regulator_voltage_ops;
+                drvdata[data_idx].desc.n_voltages = 2;
+                drvdata[data_idx].desc.enable_time = info->enable_time;
+
+                cfg.init_data = pbias_matches[idx].init_data;
+                cfg.driver_data = &drvdata[data_idx];
+                cfg.of_node = pbias_matches[idx].of_node;
+
+                drvdata[data_idx].dev = devm_regulator_register(&pdev->dev,
+                                        &drvdata[data_idx].desc, &cfg);
+                if (IS_ERR(drvdata[data_idx].dev)) {
+                        ret = PTR_ERR(drvdata[data_idx].dev);
+                        dev_err(&pdev->dev,
+                                "Failed to register regulator: %d\n", ret);
+                        goto err_regulator;
+                }
+                data_idx++;
+        }
+
+        platform_set_drvdata(pdev, drvdata);
+
+err_regulator:
+        return ret;
+}
+
+static struct platform_driver pbias_regulator_driver = {
+        .probe          = pbias_regulator_probe,
+        .driver         = {
+                .name           = "pbias-regulator",
+                .owner          = THIS_MODULE,
+                .of_match_table = of_match_ptr(pbias_of_match),
+        },
+};
+
+module_platform_driver(pbias_regulator_driver);
+
+MODULE_AUTHOR("Balaji T K <balajitk@ti.com>");
+MODULE_DESCRIPTION("pbias voltage regulator");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:pbias-regulator");