[PATCH v5 1/6] mfd: rt4831: Adds support for Richtek RT4831 core

cy_huang
2020-12-17T15:02:33Z

From: ChiYuan Huang <cy_huang@richtek.com>

This adds support Richtek RT4831 core. It includes four channel WLED driver
and Display Bias Voltage outputs.

Signed-off-by: ChiYuan Huang <cy_huang@richtek.com>
---
since v5
- Rename file name from rt4831-core.c to rt4831.c
- Change RICHTEK_VID to RICHTEK_VENDOR_ID.
- Change gpio_desc nameing from 'enable' to 'enable_gpio' in probe.
- Change variable 'val' to the meaningful name 'chip_id'.
- Refine the error log when vendor id is not matched.
- Remove of_match_ptr.

since v2
- Refine Kconfig descriptions.
- Add copyright.
- Refine error logs in probe.
- Refine comment lines in remove and shutdown.
---
drivers/mfd/Kconfig | 10 +++++
drivers/mfd/Makefile | 1 +
drivers/mfd/rt4831.c | 124 +++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 135 insertions(+)
create mode 100644 drivers/mfd/rt4831.c

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 8b99a13..dfb2640 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -1088,6 +1088,16 @@ config MFD_RDC321X
southbridge which provides access to GPIOs and Watchdog using the
southbridge PCI device configuration space.

+config MFD_RT4831
+ tristate "Richtek RT4831 four channel WLED and Display Bias Voltage"
+ depends on I2C
+ select MFD_CORE
+ select REGMAP_I2C
+ help
+ This enables support for the Richtek RT4831 that includes 4 channel
+ WLED driving and Display Bias Voltage. It's commonly used to provide
+ power to the LCD display and LCD backlight.
+
config MFD_RT5033
tristate "Richtek RT5033 Power Management IC"
depends on I2C
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 1780019..28d247b 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -235,6 +235,7 @@ obj-$(CONFIG_MFD_MENF21BMC) += menf21bmc.o
obj-$(CONFIG_MFD_HI6421_PMIC) += hi6421-pmic-core.o
obj-$(CONFIG_MFD_HI655X_PMIC) += hi655x-pmic.o
obj-$(CONFIG_MFD_DLN2) += dln2.o
+obj-$(CONFIG_MFD_RT4831) += rt4831.o
obj-$(CONFIG_MFD_RT5033) += rt5033.o
obj-$(CONFIG_MFD_SKY81452) += sky81452.o

diff --git a/drivers/mfd/rt4831.c b/drivers/mfd/rt4831.c
new file mode 100644
index 00000000..2bf8364
--- /dev/null
+++ b/drivers/mfd/rt4831.c
@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2020 Richtek Technology Corp.
+ *
+ * Author: ChiYuan Huang <cy_huang@richtek.com>
+ */
+
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/mfd/core.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#define RT4831_REG_REVISION 0x01
+#define RT4831_REG_ENABLE 0x08
+#define RT4831_REG_I2CPROT 0x15
+
+#define RICHTEK_VENDOR_ID 0x03
+#define RT4831_VID_MASK GENMASK(1, 0)
+#define RT4831_RESET_MASK BIT(7)
+#define RT4831_I2CSAFETMR_MASK BIT(0)
+
+static const struct mfd_cell rt4831_subdevs[] = {
+ OF_MFD_CELL("rt4831-backlight", NULL, NULL, 0, 0, "richtek,rt4831-backlight"),
+ MFD_CELL_NAME("rt4831-regulator")
+};
+
+static bool rt4831_is_accessible_reg(struct device *dev, unsigned int reg)
+{
+ if (reg >= RT4831_REG_REVISION && reg <= RT4831_REG_I2CPROT)
+ return true;
+ return false;
+}
+
+static const struct regmap_config rt4831_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .max_register = RT4831_REG_I2CPROT,
+
+ .readable_reg = rt4831_is_accessible_reg,
+ .writeable_reg = rt4831_is_accessible_reg,
+};
+
+static int rt4831_probe(struct i2c_client *client)
+{
+ struct gpio_desc *enable_gpio;
+ struct regmap *regmap;
+ unsigned int chip_id;
+ int ret;
+
+ enable_gpio = devm_gpiod_get_optional(&client->dev, "enable", GPIOD_OUT_HIGH);
+ if (IS_ERR(enable_gpio)) {
+ dev_err(&client->dev, "Failed to get 'enable' GPIO\n");
+ return PTR_ERR(enable_gpio);
+ }
+
+ regmap = devm_regmap_init_i2c(client, &rt4831_regmap_config);
+ if (IS_ERR(regmap)) {
+ dev_err(&client->dev, "Failed to initialize regmap\n");
+ return PTR_ERR(regmap);
+ }
+
+ ret = regmap_read(regmap, RT4831_REG_REVISION, &chip_id);
+ if (ret) {
+ dev_err(&client->dev, "Failed to get H/W revision\n");
+ return ret;
+ }
+
+ if ((chip_id & RT4831_VID_MASK) != RICHTEK_VENDOR_ID) {
+ dev_err(&client->dev, "Chip vendor ID 0x%02x not matched\n", chip_id);
+ return -ENODEV;
+ }
+
+ /*
+ * Used to prevent the abnormal shutdown.
+ * If SCL/SDA both keep low for one second to reset HW.
+ */
+ ret = regmap_update_bits(regmap, RT4831_REG_I2CPROT, RT4831_I2CSAFETMR_MASK,
+ RT4831_I2CSAFETMR_MASK);
+ if (ret) {
+ dev_err(&client->dev, "Failed to enable I2C safety timer\n");
+ return ret;
+ }
+
+ return devm_mfd_add_devices(&client->dev, PLATFORM_DEVID_AUTO, rt4831_subdevs,
+ ARRAY_SIZE(rt4831_subdevs), NULL, 0, NULL);
+}
+
+static int rt4831_remove(struct i2c_client *client)
+{
+ struct regmap *regmap = dev_get_regmap(&client->dev, NULL);
+
+ /* Disable WLED and DSV outputs */
+ return regmap_update_bits(regmap, RT4831_REG_ENABLE, RT4831_RESET_MASK, RT4831_RESET_MASK);
+}
+
+static void rt4831_shutdown(struct i2c_client *client)
+{
+ struct regmap *regmap = dev_get_regmap(&client->dev, NULL);
+
+ /* Disable WLED and DSV outputs */
+ regmap_update_bits(regmap, RT4831_REG_ENABLE, RT4831_RESET_MASK, RT4831_RESET_MASK);
+}
+
+static const struct of_device_id __maybe_unused rt4831_of_match[] = {
+ { .compatible = "richtek,rt4831", },
+ {}
+};
+MODULE_DEVICE_TABLE(of, rt4831_of_match);
+
+static struct i2c_driver rt4831_driver = {
+ .driver = {
+ .name = "rt4831",
+ .of_match_table = rt4831_of_match,
+ },
+ .probe_new = rt4831_probe,
+ .remove = rt4831_remove,
+ .shutdown = rt4831_shutdown,
+};
+module_i2c_driver(rt4831_driver);
+
+MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>");
+MODULE_LICENSE("GPL v2");
--
2.7.4