[PATCH v3 2/3] regulator: add support for SY8106A regulator

From: Icenowy Zheng
Date: Mon Apr 23 2018 - 10:48:02 EST

From: Ondrej Jirman <megous@xxxxxxxxxx>

SY8106A is an I2C attached single output regulator made by Silergy Corp,
which is used on several Allwinner H3/H5 SBCs to control the power
supply of the ARM cores.

Add a driver for it.

Signed-off-by: Ondrej Jirman <megous@xxxxxxxxxx>
[Icenowy: Change commit message, remove enable/disable code, add default
ramp_delay, add comment for go bit, add code for fixed mode voltage]
Signed-off-by: Icenowy Zheng <icenowy@xxxxxxx>
Reviewed-by: Chen-Yu Tsai <wens@xxxxxxxx>
---
Changes in v3:
- Return the fixed voltage defined in device tree when I2C regulating
not enabled (in this situation the register may contain no valid
voltage data).

Changes in v2:
- Dropped the enable/disable code.
- Added default ramp_delay value.
- Added comment for the "go bit".

MAINTAINERS | 6 ++
drivers/regulator/Kconfig | 7 ++
drivers/regulator/Makefile | 2 +-
drivers/regulator/sy8106a-regulator.c | 175 ++++++++++++++++++++++++++++++++++
4 files changed, 189 insertions(+), 1 deletion(-)
create mode 100644 drivers/regulator/sy8106a-regulator.c

diff --git a/MAINTAINERS b/MAINTAINERS
index a33643739820..e0cb78568458 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -13464,6 +13464,12 @@ S: Supported
F: net/switchdev/
F: include/net/switchdev.h

+SY8106A REGULATOR DRIVER
+M: Icenowy Zheng <icenowy@xxxxxxx>
+S: Maintained
+F: drivers/regulator/sy8106a-regulator.c
+F: Documentation/devicetree/bindings/regulator/sy8106a-regulator.txt
+
SYNC FILE FRAMEWORK
M: Sumit Semwal <sumit.semwal@xxxxxxxxxx>
R: Gustavo Padovan <gustavo@xxxxxxxxxxx>
diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index 097f61784a7d..4efae3b7e746 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -801,6 +801,13 @@ config REGULATOR_STW481X_VMMC
This driver supports the internal VMMC regulator in the STw481x
PMIC chips.

+config REGULATOR_SY8106A
+ tristate "Silergy SY8106A regulator"
+ depends on I2C && (OF || COMPILE_TEST)
+ select REGMAP_I2C
+ help
+ This driver supports SY8106A single output regulator.
+
config REGULATOR_TPS51632
tristate "TI TPS51632 Power Regulator"
depends on I2C
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index 590674fbecd7..d81fb02bd6e9 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -100,6 +100,7 @@ obj-$(CONFIG_REGULATOR_SC2731) += sc2731-regulator.o
obj-$(CONFIG_REGULATOR_SKY81452) += sky81452-regulator.o
obj-$(CONFIG_REGULATOR_STM32_VREFBUF) += stm32-vrefbuf.o
obj-$(CONFIG_REGULATOR_STW481X_VMMC) += stw481x-vmmc.o
+obj-$(CONFIG_REGULATOR_SY8106A) += sy8106a-regulator.o
obj-$(CONFIG_REGULATOR_TI_ABB) += ti-abb-regulator.o
obj-$(CONFIG_REGULATOR_TPS6105X) += tps6105x-regulator.o
obj-$(CONFIG_REGULATOR_TPS62360) += tps62360-regulator.o
@@ -125,5 +126,4 @@ obj-$(CONFIG_REGULATOR_WM8350) += wm8350-regulator.o
obj-$(CONFIG_REGULATOR_WM8400) += wm8400-regulator.o
obj-$(CONFIG_REGULATOR_WM8994) += wm8994-regulator.o

-
ccflags-$(CONFIG_REGULATOR_DEBUG) += -DDEBUG
diff --git a/drivers/regulator/sy8106a-regulator.c b/drivers/regulator/sy8106a-regulator.c
new file mode 100644
index 000000000000..6dbe41044ab9
--- /dev/null
+++ b/drivers/regulator/sy8106a-regulator.c
@@ -0,0 +1,176 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * sy8106a-regulator.c - Regulator device driver for SY8106A
+ *
+ * Copyright (C) 2016 OndÅej Jirman <megous@xxxxxxxxxx>
+ * Copyright (c) 2017-2018 Icenowy Zheng <icenowy@xxxxxxx>
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/of_regulator.h>
+
+#define SY8106A_REG_VOUT1_SEL 0x01
+#define SY8106A_REG_VOUT_COM 0x02
+#define SY8106A_REG_VOUT1_SEL_MASK 0x7f
+#define SY8106A_DISABLE_REG BIT(0)
+/*
+ * The I2C controlled voltage will only work when this bit is set; otherwise
+ * it will behave like a fixed regulator.
+ */
+#define SY8106A_GO_BIT BIT(7)
+
+struct sy8106a {
+ struct regulator_dev *rdev;
+ struct regmap *regmap;
+ u32 fixed_voltage;
+};
+
+static const struct regmap_config sy8106a_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+};
+
+static int sy8106a_set_voltage_sel(struct regulator_dev *rdev, unsigned int sel)
+{
+ /* We use our set_voltage_sel in order to avoid unnecessary I2C
+ * chatter, because the regulator_get_voltage_sel_regmap using
+ * apply_bit would perform 4 unnecessary transfers instead of one,
+ * increasing the chance of error.
+ */
+ return regmap_write(rdev->regmap, rdev->desc->vsel_reg,
+ sel | SY8106A_GO_BIT);
+}
+
+static int sy8106a_get_voltage_sel(struct regulator_dev *rdev)
+{
+ struct sy8106a *chip = rdev_get_drvdata(rdev);
+ unsigned int reg;
+ int error;
+
+ error = regmap_read(rdev->regmap, rdev->desc->vsel_reg, &reg);
+ if (error)
+ return error;
+
+ if (reg & SY8106A_GO_BIT)
+ return reg & rdev->desc->vsel_mask;
+ else
+ return (chip->fixed_voltage - rdev->desc->min_uV) /
+ rdev->desc->uV_step;
+}
+
+static const struct regulator_ops sy8106a_ops = {
+ .set_voltage_sel = sy8106a_set_voltage_sel,
+ .set_voltage_time_sel = regulator_set_voltage_time_sel,
+ .get_voltage_sel = sy8106a_get_voltage_sel,
+ .list_voltage = regulator_list_voltage_linear,
+ /* Enabling/disabling the regulator is not yet implemented */
+};
+
+/* Default limits measured in millivolts */
+#define SY8106A_MIN_MV 680
+#define SY8106A_MAX_MV 1950
+#define SY8106A_STEP_MV 10
+
+static const struct regulator_desc sy8106a_reg = {
+ .name = "SY8106A",
+ .id = 0,
+ .ops = &sy8106a_ops,
+ .type = REGULATOR_VOLTAGE,
+ .n_voltages = ((SY8106A_MAX_MV - SY8106A_MIN_MV) / SY8106A_STEP_MV) + 1,
+ .min_uV = (SY8106A_MIN_MV * 1000),
+ .uV_step = (SY8106A_STEP_MV * 1000),
+ .vsel_reg = SY8106A_REG_VOUT1_SEL,
+ .vsel_mask = SY8106A_REG_VOUT1_SEL_MASK,
+ /*
+ * This ramp_delay is a conservative default value which works on
+ * H3/H5 boards VDD-CPUX situations.
+ */
+ .ramp_delay = 200,
+ .owner = THIS_MODULE,
+};
+
+/*
+ * I2C driver interface functions
+ */
+static int sy8106a_i2c_probe(struct i2c_client *i2c,
+ const struct i2c_device_id *id)
+{
+ struct sy8106a *chip;
+ struct device *dev = &i2c->dev;
+ struct regulator_dev *rdev = NULL;
+ struct regulator_config config = { };
+ int error;
+
+ chip = devm_kzalloc(&i2c->dev, sizeof(struct sy8106a), GFP_KERNEL);
+ if (!chip)
+ return -ENOMEM;
+
+ error = of_property_read_u32(dev->of_node, "silergy,fixed-microvolt",
+ &chip->fixed_voltage);
+ if (error)
+ return error;
+
+ chip->regmap = devm_regmap_init_i2c(i2c, &sy8106a_regmap_config);
+ if (IS_ERR(chip->regmap)) {
+ error = PTR_ERR(chip->regmap);
+ dev_err(dev, "Failed to allocate register map: %d\n", error);
+ return error;
+ }
+
+ config.dev = &i2c->dev;
+ config.regmap = chip->regmap;
+ config.driver_data = chip;
+
+ config.of_node = dev->of_node;
+ config.init_data = of_get_regulator_init_data(dev, dev->of_node,
+ &sy8106a_reg);
+
+ if (!config.init_data)
+ return -ENOMEM;
+
+ /* Probe regulator */
+ rdev = devm_regulator_register(&i2c->dev, &sy8106a_reg, &config);
+ if (IS_ERR(rdev)) {
+ error = PTR_ERR(rdev);
+ dev_err(&i2c->dev, "Failed to register SY8106A regulator: %d\n", error);
+ return error;
+ }
+
+ chip->rdev = rdev;
+
+ i2c_set_clientdata(i2c, chip);
+
+ return 0;
+}
+
+static const struct of_device_id sy8106a_i2c_of_match[] = {
+ { .compatible = "silergy,sy8106a" },
+ { },
+};
+MODULE_DEVICE_TABLE(of, sy8106a_i2c_of_match);
+
+static const struct i2c_device_id sy8106a_i2c_id[] = {
+ { "sy8106a", 0 },
+ { },
+};
+MODULE_DEVICE_TABLE(i2c, sy8106a_i2c_id);
+
+static struct i2c_driver sy8106a_regulator_driver = {
+ .driver = {
+ .name = "sy8106a",
+ .of_match_table = of_match_ptr(sy8106a_i2c_of_match),
+ },
+ .probe = sy8106a_i2c_probe,
+ .id_table = sy8106a_i2c_id,
+};
+
+module_i2c_driver(sy8106a_regulator_driver);
+
+MODULE_AUTHOR("OndÅej Jirman <megous@xxxxxxxxxx>");
+MODULE_AUTHOR("Icenowy Zheng <icenowy@xxxxxxx>");
+MODULE_DESCRIPTION("Regulator device driver for Silergy SY8106A");
+MODULE_LICENSE("GPL");
--
2.15.1