regulator: pbias: Add PBIAS regulator for proper voltage switching on MMC1

In the TI SOCs a PBIAS cell exists to provide a bias voltage to the MMC1
IO cells. Without this bias voltage these I/O cells can not function
properly. The PBIAS cell is controlled by software.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

4 files changed, 316 insertions, 0 deletions

diff --git a/drivers/mmc/Kconfig b/drivers/mmc/Kconfig
index 4429292c05..fa24c52351 100644
--- a/drivers/mmc/Kconfig
+++ b/drivers/mmc/Kconfig
@@ -136,6 +136,7 @@ config MMC_PCI
 config MMC_OMAP_HS
 	bool "TI OMAP High Speed Multimedia Card Interface support"
 	select DM_REGULATOR_PBIAS if DM_MMC && DM_REGULATOR
+	select DM_REGULATOR_PBIAS if DM_MMC && DM_REGULATOR
 	help
 	  This selects the TI OMAP High Speed Multimedia card Interface.
 	  If you have an omap2plus board with a Multimedia Card slot,
diff --git a/drivers/power/regulator/Kconfig b/drivers/power/regulator/Kconfig
index c82a936e8a..2cfade1cb2 100644
--- a/drivers/power/regulator/Kconfig
+++ b/drivers/power/regulator/Kconfig
@@ -151,6 +151,19 @@ config DM_REGULATOR_PALMAS
 	features for REGULATOR PALMAS and the family of PALMAS PMICs.
 	The driver implements get/set api for: value and enable.
 
+config DM_REGULATOR_PBIAS
+	bool "Enable driver for PBIAS regulator"
+	depends on DM_REGULATOR
+	select REGMAP
+	select SYSCON
+	---help---
+	This enables implementation of driver-model regulator uclass
+	features for pseudo-regulator PBIAS found in the OMAP SOCs.
+	This pseudo-regulator is used to provide a BIAS voltage to MMC1
+	signal pads and must be configured properly during a voltage switch.
+	Voltage switching is required by some operating modes of SDcards and
+	eMMC.
+
 config DM_REGULATOR_LP873X
 	bool "Enable driver for LP873X PMIC regulators"
         depends on PMIC_LP873X
diff --git a/drivers/power/regulator/Makefile b/drivers/power/regulator/Makefile
index 18fb870e43..6c149a9263 100644
--- a/drivers/power/regulator/Makefile
+++ b/drivers/power/regulator/Makefile
@@ -18,5 +18,6 @@ obj-$(CONFIG_REGULATOR_S5M8767) += s5m8767.o
 obj-$(CONFIG_DM_REGULATOR_SANDBOX) += sandbox.o
 obj-$(CONFIG_REGULATOR_TPS65090) += tps65090_regulator.o
 obj-$(CONFIG_$(SPL_)DM_REGULATOR_PALMAS) += palmas_regulator.o
+obj-$(CONFIG_$(SPL_)DM_REGULATOR_PBIAS) += pbias_regulator.o
 obj-$(CONFIG_$(SPL_)DM_REGULATOR_LP873X) += lp873x_regulator.o
 obj-$(CONFIG_$(SPL_)DM_REGULATOR_LP87565) += lp87565_regulator.o
diff --git a/drivers/power/regulator/pbias_regulator.c b/drivers/power/regulator/pbias_regulator.c
new file mode 100644
index 0000000000..914500b729
--- /dev/null
+++ b/drivers/power/regulator/pbias_regulator.c
@@ -0,0 +1,301 @@
+/*
+ * (C) Copyright 2016 Texas Instruments Incorporated, <www.ti.com>
+ * Jean-Jacques Hiblot <jjhiblot@ti.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <errno.h>
+#include <dm.h>
+#include <power/pmic.h>
+#include <power/regulator.h>
+#include <regmap.h>
+#include <syscon.h>
+#include <linux/bitops.h>
+#include <linux/ioport.h>
+#include <dm/read.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct pbias_reg_info {
+	u32 enable;
+	u32 enable_mask;
+	u32 disable_val;
+	u32 vmode;
+	unsigned int enable_time;
+	char *name;
+};
+
+struct pbias_priv {
+	struct regmap *regmap;
+	int offset;
+};
+
+static const struct pmic_child_info pmic_children_info[] = {
+	{ .prefix = "pbias", .driver = "pbias_regulator"},
+	{ },
+};
+
+static int pbias_write(struct udevice *dev, uint reg, const uint8_t *buff,
+		       int len)
+{
+	struct pbias_priv *priv = dev_get_priv(dev);
+	u32 val = *(u32 *)buff;
+
+	if (len != 4)
+		return -EINVAL;
+
+	return regmap_write(priv->regmap, priv->offset, val);
+}
+
+static int pbias_read(struct udevice *dev, uint reg, uint8_t *buff, int len)
+{
+	struct pbias_priv *priv = dev_get_priv(dev);
+
+	if (len != 4)
+		return -EINVAL;
+
+	return regmap_read(priv->regmap, priv->offset, (u32 *)buff);
+}
+
+static int pbias_ofdata_to_platdata(struct udevice *dev)
+{
+	struct pbias_priv *priv = dev_get_priv(dev);
+	struct udevice *syscon;
+	struct regmap *regmap;
+	struct resource res;
+	int err;
+
+	err = uclass_get_device_by_phandle(UCLASS_SYSCON, dev,
+					   "syscon", &syscon);
+	if (err) {
+		error("%s: unable to find syscon device (%d)\n", __func__,
+		      err);
+		return err;
+	}
+
+	regmap = syscon_get_regmap(syscon);
+	if (IS_ERR(regmap)) {
+		error("%s: unable to find regmap (%ld)\n", __func__,
+		      PTR_ERR(regmap));
+		return PTR_ERR(regmap);
+	}
+	priv->regmap = regmap;
+
+	err = dev_read_resource(dev, 0, &res);
+	if (err) {
+		error("%s: unable to find offset (%d)\n", __func__, err);
+		return err;
+	}
+	priv->offset = res.start;
+
+	return 0;
+}
+
+static int pbias_bind(struct udevice *dev)
+{
+	int children;
+
+	children = pmic_bind_children(dev, dev->node, pmic_children_info);
+	if (!children)
+		debug("%s: %s - no child found\n", __func__, dev->name);
+
+	return 0;
+}
+
+static struct dm_pmic_ops pbias_ops = {
+	.read = pbias_read,
+	.write = pbias_write,
+};
+
+static const struct udevice_id pbias_ids[] = {
+	{ .compatible = "ti,pbias-dra7" },
+	{ }
+};
+
+U_BOOT_DRIVER(pbias_pmic) = {
+	.name = "pbias_pmic",
+	.id = UCLASS_PMIC,
+	.of_match = pbias_ids,
+	.bind = pbias_bind,
+	.ops = &pbias_ops,
+	.ofdata_to_platdata = pbias_ofdata_to_platdata,
+	.priv_auto_alloc_size = sizeof(struct pbias_priv),
+};
+
+static const struct pbias_reg_info pbias_mmc_omap2430 = {
+	.enable = BIT(1),
+	.enable_mask = BIT(1),
+	.vmode = BIT(0),
+	.disable_val = 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),
+	.disable_val = BIT(25),
+	.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),
+	.disable_val = BIT(25),
+	.vmode = BIT(21),
+	.enable_time = 100,
+	.name = "pbias_mmc_omap5"
+};
+
+static const struct pbias_reg_info *pbias_reg_infos[] = {
+	&pbias_mmc_omap5,
+	&pbias_mmc_omap4,
+	&pbias_sim_omap3,
+	&pbias_mmc_omap2430,
+	NULL
+};
+
+static int pbias_regulator_probe(struct udevice *dev)
+{
+	const struct pbias_reg_info **p = pbias_reg_infos;
+	struct dm_regulator_uclass_platdata *uc_pdata;
+
+	uc_pdata = dev_get_uclass_platdata(dev);
+
+	while (*p) {
+		int rc;
+
+		rc = dev_read_stringlist_search(dev, "regulator-name",
+						(*p)->name);
+		if (rc >= 0) {
+			debug("found regulator %s\n", (*p)->name);
+			break;
+		} else if (rc != -ENODATA) {
+			return rc;
+		}
+		p++;
+	}
+	if (!*p) {
+		int i = 0;
+		const char *s;
+
+		debug("regulator ");
+		while (dev_read_string_index(dev, "regulator-name", i++, &s) >= 0)
+			debug("%s'%s' ", (i > 1) ? ", " : "", s);
+		debug("%s not supported\n", (i > 2) ? "are" : "is");
+		return -EINVAL;
+	}
+
+	uc_pdata->type = REGULATOR_TYPE_OTHER;
+	dev->priv = (void *)*p;
+
+	return 0;
+}
+
+static int pbias_regulator_get_value(struct udevice *dev)
+{
+	const struct pbias_reg_info *p = dev_get_priv(dev);
+	int rc;
+	u32 reg;
+
+	rc = pmic_read(dev->parent, 0, (uint8_t *)&reg, sizeof(reg));
+	if (rc)
+		return rc;
+
+	debug("%s voltage id %s\n", p->name,
+	      (reg & p->vmode) ? "3.0v" : "1.8v");
+	return (reg & p->vmode) ? 3000000 : 1800000;
+}
+
+static int pbias_regulator_set_value(struct udevice *dev, int uV)
+{
+	const struct pbias_reg_info *p = dev_get_priv(dev);
+	int rc;
+	u32 reg;
+
+	debug("Setting %s voltage to %s\n", p->name,
+	      (reg & p->vmode) ? "3.0v" : "1.8v");
+
+	rc = pmic_read(dev->parent, 0, (uint8_t *)&reg, sizeof(reg));
+	if (rc)
+		return rc;
+
+	if (uV == 3000000)
+		reg |= p->vmode;
+	else if (uV == 1800000)
+		reg &= ~p->vmode;
+	else
+		return -EINVAL;
+
+	return pmic_write(dev->parent, 0, (uint8_t *)&reg, sizeof(reg));
+}
+
+static int pbias_regulator_get_enable(struct udevice *dev)
+{
+	const struct pbias_reg_info *p = dev_get_priv(dev);
+	int rc;
+	u32 reg;
+
+	rc = pmic_read(dev->parent, 0, (uint8_t *)&reg, sizeof(reg));
+	if (rc)
+		return rc;
+
+	debug("%s id %s\n", p->name,
+	      (reg & p->enable_mask) == (p->disable_val) ? "on" : "off");
+
+	return (reg & p->enable_mask) == (p->disable_val);
+}
+
+static int pbias_regulator_set_enable(struct udevice *dev, bool enable)
+{
+	const struct pbias_reg_info *p = dev_get_priv(dev);
+	int rc;
+	u32 reg;
+
+	debug("Turning %s %s\n", enable ? "on" : "off", p->name);
+
+	rc = pmic_read(dev->parent, 0, (uint8_t *)&reg, sizeof(reg));
+	if (rc)
+		return rc;
+
+	reg &= ~p->enable_mask;
+	if (enable)
+		reg |= p->enable;
+	else
+		reg |= p->disable_val;
+
+	rc = pmic_write(dev->parent, 0, (uint8_t *)&reg, sizeof(reg));
+	if (rc)
+		return rc;
+
+	if (enable)
+		udelay(p->enable_time);
+
+	return 0;
+}
+
+static const struct dm_regulator_ops pbias_regulator_ops = {
+	.get_value  = pbias_regulator_get_value,
+	.set_value  = pbias_regulator_set_value,
+	.get_enable = pbias_regulator_get_enable,
+	.set_enable = pbias_regulator_set_enable,
+};
+
+U_BOOT_DRIVER(pbias_regulator) = {
+	.name = "pbias_regulator",
+	.id = UCLASS_REGULATOR,
+	.ops = &pbias_regulator_ops,
+	.probe = pbias_regulator_probe,
+};