mfd: rt4831: Adds support for Richtek RT4831

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>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 5c408c1..40cb07b 100644 (file)
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -1077,6 +1077,16 @@ 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 4f6d2b8..eb42bd4 100644 (file)
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -234,6 +234,7 @@ 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 (file)
index 0000000..b169781
--- /dev/null
+++ b/drivers/mfd/rt4831.c
@@ -0,0 +1,115 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2021 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[] = {
+       MFD_CELL_OF("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 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,
+};
+module_i2c_driver(rt4831_driver);
+
+MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>");
+MODULE_LICENSE("GPL v2");