power: regulator: add driver for ANATOP regulator

Anatop is an integrated regulator inside i.MX6 SoC.
There are 3 digital regulators which controls PU, CORE (ARM), and SOC.
And 3 analog regulators which controls 1P1, 2P5, 3P0 (USB).
This patch adds the Anatop regulator driver.

Signed-off-by: Ying-Chun Liu (PaulLiu) <paul.liu@linaro.org>
Reviewed-by: Sean Anderson <sean.anderson@seco.com>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Jaehoon Chung <jh80.chung@samsung.com>
Cc: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>

drivers/power/regulator/Kconfig

@@ -312,6 +312,16 @@ config DM_REGULATOR_STPMIC1
 	by the PMIC device. This driver is controlled by a device tree node
 	which includes voltage limits.
 
+config DM_REGULATOR_ANATOP
+	bool "Enable driver for ANATOP regulators"
+	depends on DM_REGULATOR
+	select REGMAP
+	select SYSCON
+	help
+	Enable support for the Freescale i.MX on-chip ANATOP LDO
+	regulators. It is recommended that this option be enabled on
+	i.MX6 platform.
+
 config SPL_DM_REGULATOR_STPMIC1
 	bool "Enable driver for STPMIC1 regulators in SPL"
 	depends on SPL_DM_REGULATOR && PMIC_STPMIC1

drivers/power/regulator/Makefile

@@ -31,3 +31,4 @@ obj-$(CONFIG_DM_REGULATOR_TPS62360) += tps62360_regulator.o
 obj-$(CONFIG_$(SPL_)DM_REGULATOR_STPMIC1) += stpmic1.o
 obj-$(CONFIG_DM_REGULATOR_TPS65941) += tps65941_regulator.o
 obj-$(CONFIG_DM_REGULATOR_SCMI) += scmi_regulator.o
+obj-$(CONFIG_$(SPL_)DM_REGULATOR_ANATOP) += anatop_regulator.o

drivers/power/regulator/anatop_regulator.c

@@ -0,0 +1,278 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2011 Freescale Semiconductor, Inc. All Rights Reserved.
+ * Copyright (C) 2021 Linaro
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <log.h>
+#include <regmap.h>
+#include <syscon.h>
+#include <dm/device-internal.h>
+#include <dm/device_compat.h>
+#include <linux/bitops.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/ioport.h>
+#include <power/pmic.h>
+#include <power/regulator.h>
+
+#define LDO_RAMP_UP_UNIT_IN_CYCLES      64 /* 64 cycles per step */
+#define LDO_RAMP_UP_FREQ_IN_MHZ         24 /* cycle based on 24M OSC */
+
+#define LDO_POWER_GATE			0x00
+#define LDO_FET_FULL_ON			0x1f
+
+#define BIT_WIDTH_MAX			32
+
+#define ANATOP_REGULATOR_STEP		25000
+#define MIN_DROPOUT_UV			125000
+
+struct anatop_regulator {
+	const char *name;
+	struct regmap *regmap;
+	struct udevice *supply;
+	u32 control_reg;
+	u32 vol_bit_shift;
+	u32 vol_bit_width;
+	u32 min_bit_val;
+	u32 min_voltage;
+	u32 max_voltage;
+	u32 delay_reg;
+	u32 delay_bit_shift;
+	u32 delay_bit_width;
+};
+
+static u32 anatop_get_bits(struct udevice *dev, u32 addr, int bit_shift,
+			   int bit_width)
+{
+	const struct anatop_regulator *anatop_reg = dev_get_plat(dev);
+	int err;
+	u32 val, mask;
+
+	if (bit_width == BIT_WIDTH_MAX)
+		mask = ~0;
+	else
+		mask = (1 << bit_width) - 1;
+
+	err = regmap_read(anatop_reg->regmap, addr, &val);
+	if (err) {
+		dev_dbg(dev, "cannot read reg (%d)\n", err);
+		return err;
+	}
+
+	val = (val >> bit_shift) & mask;
+
+	return val;
+}
+
+static int anatop_set_bits(struct udevice *dev, u32 addr, int bit_shift,
+			   int bit_width, u32 data)
+{
+	const struct anatop_regulator *anatop_reg = dev_get_plat(dev);
+	int err;
+	u32 val, mask;
+
+	if (bit_width == 32)
+		mask = ~0;
+	else
+		mask = (1 << bit_width) - 1;
+
+	err = regmap_read(anatop_reg->regmap, addr, &val);
+	if (err) {
+		dev_dbg(dev, "cannot read reg (%d)\n", err);
+		return err;
+	}
+	val = val & ~(mask << bit_shift);
+	err = regmap_write(anatop_reg->regmap,
+			   addr, (data << bit_shift) | val);
+	if (err) {
+		dev_dbg(dev, "cannot write reg (%d)\n", err);
+		return err;
+	}
+
+	return 0;
+}
+
+static int anatop_get_voltage(struct udevice *dev)
+{
+	const struct anatop_regulator *anatop_reg = dev_get_plat(dev);
+	u32 sel;
+	u32 val;
+
+	if (!anatop_reg->control_reg)
+		return -ENOSYS;
+
+	val = anatop_get_bits(dev,
+			      anatop_reg->control_reg,
+			      anatop_reg->vol_bit_shift,
+			      anatop_reg->vol_bit_width);
+
+	sel = val - anatop_reg->min_bit_val;
+
+	return sel * ANATOP_REGULATOR_STEP + anatop_reg->min_voltage;
+}
+
+static int anatop_set_voltage(struct udevice *dev, int uV)
+{
+	const struct anatop_regulator *anatop_reg = dev_get_plat(dev);
+	u32 val;
+	u32 sel;
+	int ret;
+
+	dev_dbg(dev, "uv %d, min %d, max %d\n", uV, anatop_reg->min_voltage,
+		anatop_reg->max_voltage);
+
+	if (uV < anatop_reg->min_voltage)
+		return -EINVAL;
+
+	if (!anatop_reg->control_reg)
+		return -ENOSYS;
+
+	sel = DIV_ROUND_UP(uV - anatop_reg->min_voltage,
+			   ANATOP_REGULATOR_STEP);
+	if (sel * ANATOP_REGULATOR_STEP + anatop_reg->min_voltage >
+	    anatop_reg->max_voltage)
+		return -EINVAL;
+	val = anatop_reg->min_bit_val + sel;
+	dev_dbg(dev, "calculated val %d\n", val);
+
+	if (anatop_reg->supply) {
+		ret = regulator_set_value(anatop_reg->supply,
+					  uV + MIN_DROPOUT_UV);
+		if (ret)
+			return ret;
+	}
+
+	ret = anatop_set_bits(dev,
+			      anatop_reg->control_reg,
+			      anatop_reg->vol_bit_shift,
+			      anatop_reg->vol_bit_width,
+			      val);
+
+	return ret;
+}
+
+static const struct dm_regulator_ops anatop_regulator_ops = {
+	.set_value = anatop_set_voltage,
+	.get_value = anatop_get_voltage,
+};
+
+static int anatop_regulator_probe(struct udevice *dev)
+{
+	struct anatop_regulator *anatop_reg;
+	struct dm_regulator_uclass_plat *uc_pdata;
+	struct udevice *syscon;
+	int ret = 0;
+	u32 val;
+
+	anatop_reg = dev_get_plat(dev);
+	uc_pdata = dev_get_uclass_plat(dev);
+
+	anatop_reg->name = ofnode_read_string(dev_ofnode(dev),
+					      "regulator-name");
+	if (!anatop_reg->name)
+		return log_msg_ret("regulator-name", -EINVAL);
+
+	ret = device_get_supply_regulator(dev, "vin-supply",
+					  &anatop_reg->supply);
+	if (ret != -ENODEV) {
+		if (ret)
+			return log_msg_ret("get vin-supply", ret);
+
+		ret = regulator_set_enable(anatop_reg->supply, true);
+		if (ret)
+			return ret;
+	}
+
+	ret = dev_read_u32(dev,
+			   "anatop-reg-offset",
+			   &anatop_reg->control_reg);
+	if (ret)
+		return log_msg_ret("anatop-reg-offset", ret);
+
+	ret = dev_read_u32(dev,
+			   "anatop-vol-bit-width",
+			   &anatop_reg->vol_bit_width);
+	if (ret)
+		return log_msg_ret("anatop-vol-bit-width", ret);
+
+	ret = dev_read_u32(dev,
+			   "anatop-vol-bit-shift",
+			   &anatop_reg->vol_bit_shift);
+	if (ret)
+		return log_msg_ret("anatop-vol-bit-shift", ret);
+
+	ret = dev_read_u32(dev,
+			   "anatop-min-bit-val",
+			   &anatop_reg->min_bit_val);
+	if (ret)
+		return log_msg_ret("anatop-min-bit-val", ret);
+
+	ret = dev_read_u32(dev,
+			   "anatop-min-voltage",
+			   &anatop_reg->min_voltage);
+	if (ret)
+		return log_msg_ret("anatop-min-voltage", ret);
+
+	ret = dev_read_u32(dev,
+			   "anatop-max-voltage",
+			   &anatop_reg->max_voltage);
+	if (ret)
+		return log_msg_ret("anatop-max-voltage", ret);
+
+	/* read LDO ramp up setting, only for core reg */
+	dev_read_u32(dev, "anatop-delay-reg-offset",
+		     &anatop_reg->delay_reg);
+	dev_read_u32(dev, "anatop-delay-bit-width",
+		     &anatop_reg->delay_bit_width);
+	dev_read_u32(dev, "anatop-delay-bit-shift",
+		     &anatop_reg->delay_bit_shift);
+
+	syscon = dev_get_parent(dev);
+	if (!syscon) {
+		dev_dbg(dev, "unable to find syscon device\n");
+		return -ENOENT;
+	}
+
+	anatop_reg->regmap = syscon_get_regmap(syscon);
+	if (IS_ERR(anatop_reg->regmap)) {
+		dev_dbg(dev, "unable to find regmap (%ld)\n",
+			PTR_ERR(anatop_reg->regmap));
+		return -ENOENT;
+	}
+
+	/* check whether need to care about LDO ramp up speed */
+	if (anatop_reg->delay_bit_width) {
+		/*
+		 * the delay for LDO ramp up time is
+		 * based on the register setting, we need
+		 * to calculate how many steps LDO need to
+		 * ramp up, and how much delay needed. (us)
+		 */
+		val = anatop_get_bits(dev,
+				      anatop_reg->delay_reg,
+				      anatop_reg->delay_bit_shift,
+				      anatop_reg->delay_bit_width);
+		uc_pdata->ramp_delay = (LDO_RAMP_UP_UNIT_IN_CYCLES << val)
+			/ LDO_RAMP_UP_FREQ_IN_MHZ + 1;
+	}
+
+	return 0;
+}
+
+static const struct udevice_id of_anatop_regulator_match_tbl[] = {
+	{ .compatible = "fsl,anatop-regulator", },
+	{ /* end */ }
+};
+
+U_BOOT_DRIVER(anatop_regulator) = {
+	.name = "anatop_regulator",
+	.id = UCLASS_REGULATOR,
+	.ops = &anatop_regulator_ops,
+	.of_match = of_anatop_regulator_match_tbl,
+	.plat_auto = sizeof(struct anatop_regulator),
+	.probe = anatop_regulator_probe,
+};