regulator: Add Renesas PMIC RAA215300 driver

The RAA215300 is a 9-channel PMIC that consists of
 * Internally compensated regulators
 * built-in Real Time Clock (RTC)
 * 32kHz crystal oscillator
 * coin cell battery charger

The RTC on RAA215300 is similar to the IP found in the ISL1208.
The existing driver for the ISL1208 works for this PMIC too,
however the RAA215300 exposes two devices via I2C, one for the RTC
IP, and one for everything else. The RTC IP has to be enabled
by the other I2C device, therefore this driver is necessary to get
the RTC to work.

The external oscillator bit is inverted on PMIC version 0x11.

Add PMIC RAA215300 driver for enabling RTC block and instantiating
RTC device based on PMIC version.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://lore.kernel.org/r/Message-Id: <20230623140948.384762-3-biju.das.jz@bp.renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/Kconfig

@@ -1033,6 +1033,13 @@ config REGULATOR_QCOM_USB_VBUS
 	  Say M here if you want to include support for enabling the VBUS output
 	  as a module. The module will be named "qcom_usb_vbus_regulator".
 
+config REGULATOR_RAA215300
+	tristate "Renesas RAA215300 driver"
+	select REGMAP_I2C
+	depends on I2C
+	help
+	  Support for the Renesas RAA215300 PMIC.
+
 config REGULATOR_RASPBERRYPI_TOUCHSCREEN_ATTINY
 	tristate "Raspberry Pi 7-inch touchscreen panel ATTINY regulator"
 	depends on BACKLIGHT_CLASS_DEVICE

drivers/regulator/Makefile

@@ -124,6 +124,7 @@ obj-$(CONFIG_REGULATOR_TPS51632) += tps51632-regulator.o
 obj-$(CONFIG_REGULATOR_PBIAS) += pbias-regulator.o
 obj-$(CONFIG_REGULATOR_PCAP) += pcap-regulator.o
 obj-$(CONFIG_REGULATOR_PCF50633) += pcf50633-regulator.o
+obj-$(CONFIG_REGULATOR_RAA215300) += raa215300.o
 obj-$(CONFIG_REGULATOR_RASPBERRYPI_TOUCHSCREEN_ATTINY)  += rpi-panel-attiny-regulator.o
 obj-$(CONFIG_REGULATOR_RC5T583)  += rc5t583-regulator.o
 obj-$(CONFIG_REGULATOR_RK808)   += rk808-regulator.o

drivers/regulator/raa215300.c

@@ -0,0 +1,190 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Renesas RAA215300 PMIC driver
+//
+// Copyright (C) 2023 Renesas Electronics Corporation
+//
+
+#include <linux/clk.h>
+#include <linux/clkdev.h>
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+
+#define RAA215300_FAULT_LATCHED_STATUS_1	0x59
+#define RAA215300_FAULT_LATCHED_STATUS_2	0x5a
+#define RAA215300_FAULT_LATCHED_STATUS_3	0x5b
+#define RAA215300_FAULT_LATCHED_STATUS_4	0x5c
+#define RAA215300_FAULT_LATCHED_STATUS_6	0x5e
+
+#define RAA215300_INT_MASK_1	0x64
+#define RAA215300_INT_MASK_2	0x65
+#define RAA215300_INT_MASK_3	0x66
+#define RAA215300_INT_MASK_4	0x67
+#define RAA215300_INT_MASK_6	0x68
+
+#define RAA215300_REG_BLOCK_EN	0x6c
+#define RAA215300_HW_REV	0xf8
+
+#define RAA215300_INT_MASK_1_ALL	GENMASK(5, 0)
+#define RAA215300_INT_MASK_2_ALL	GENMASK(3, 0)
+#define RAA215300_INT_MASK_3_ALL	GENMASK(5, 0)
+#define RAA215300_INT_MASK_4_ALL	BIT(0)
+#define RAA215300_INT_MASK_6_ALL	GENMASK(7, 0)
+
+#define RAA215300_REG_BLOCK_EN_RTC_EN	BIT(6)
+#define RAA215300_RTC_DEFAULT_ADDR	0x6f
+
+const char *clkin_name = "clkin";
+const char *xin_name = "xin";
+static struct clk *clk;
+
+static const struct regmap_config raa215300_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = 0xff,
+};
+
+static void raa215300_rtc_unregister_device(void *data)
+{
+	i2c_unregister_device(data);
+	if (!clk) {
+		clk_unregister_fixed_rate(clk);
+		clk = NULL;
+	}
+}
+
+static int raa215300_clk_present(struct i2c_client *client, const char *name)
+{
+	struct clk *clk;
+
+	clk = devm_clk_get_optional(&client->dev, name);
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	return !!clk;
+}
+
+static int raa215300_i2c_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	const char *clk_name = xin_name;
+	unsigned int pmic_version, val;
+	struct regmap *regmap;
+	int ret;
+
+	regmap = devm_regmap_init_i2c(client, &raa215300_regmap_config);
+	if (IS_ERR(regmap))
+		return dev_err_probe(dev, PTR_ERR(regmap),
+				     "regmap i2c init failed\n");
+
+	ret = regmap_read(regmap, RAA215300_HW_REV, &pmic_version);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "HW rev read failed\n");
+
+	dev_dbg(dev, "RAA215300 PMIC version 0x%04x\n", pmic_version);
+
+	/* Clear all blocks except RTC, if enabled */
+	regmap_read(regmap, RAA215300_REG_BLOCK_EN, &val);
+	val &= RAA215300_REG_BLOCK_EN_RTC_EN;
+	regmap_write(regmap, RAA215300_REG_BLOCK_EN, val);
+
+	/*Clear the latched registers */
+	regmap_read(regmap, RAA215300_FAULT_LATCHED_STATUS_1, &val);
+	regmap_write(regmap, RAA215300_FAULT_LATCHED_STATUS_1, val);
+	regmap_read(regmap, RAA215300_FAULT_LATCHED_STATUS_2, &val);
+	regmap_write(regmap, RAA215300_FAULT_LATCHED_STATUS_2, val);
+	regmap_read(regmap, RAA215300_FAULT_LATCHED_STATUS_3, &val);
+	regmap_write(regmap, RAA215300_FAULT_LATCHED_STATUS_3, val);
+	regmap_read(regmap, RAA215300_FAULT_LATCHED_STATUS_4, &val);
+	regmap_write(regmap, RAA215300_FAULT_LATCHED_STATUS_4, val);
+	regmap_read(regmap, RAA215300_FAULT_LATCHED_STATUS_6, &val);
+	regmap_write(regmap, RAA215300_FAULT_LATCHED_STATUS_6, val);
+
+	/* Mask all the PMIC interrupts */
+	regmap_write(regmap, RAA215300_INT_MASK_1, RAA215300_INT_MASK_1_ALL);
+	regmap_write(regmap, RAA215300_INT_MASK_2, RAA215300_INT_MASK_2_ALL);
+	regmap_write(regmap, RAA215300_INT_MASK_3, RAA215300_INT_MASK_3_ALL);
+	regmap_write(regmap, RAA215300_INT_MASK_4, RAA215300_INT_MASK_4_ALL);
+	regmap_write(regmap, RAA215300_INT_MASK_6, RAA215300_INT_MASK_6_ALL);
+
+	ret = raa215300_clk_present(client, xin_name);
+	if (ret < 0) {
+		return ret;
+	} else if (!ret) {
+		ret = raa215300_clk_present(client, clkin_name);
+		if (ret < 0)
+			return ret;
+
+		clk_name = clkin_name;
+	}
+
+	if (ret) {
+		char *name = pmic_version >= 0x12 ? "isl1208" : "raa215300_a0";
+		struct device_node *np = client->dev.of_node;
+		u32 addr = RAA215300_RTC_DEFAULT_ADDR;
+		struct i2c_board_info info = {};
+		struct i2c_client *rtc_client;
+		ssize_t size;
+
+		clk = clk_register_fixed_rate(NULL, clk_name, NULL, 0, 32000);
+		clk_register_clkdev(clk, clk_name, NULL);
+
+		if (np) {
+			int i;
+
+			i = of_property_match_string(np, "reg-names", "rtc");
+			if (i >= 0)
+				of_property_read_u32_index(np, "reg", i, &addr);
+		}
+
+		info.addr = addr;
+		if (client->irq > 0)
+			info.irq = client->irq;
+
+		size = strscpy(info.type, name, sizeof(info.type));
+		if (size < 0)
+			return dev_err_probe(dev, size,
+					     "Invalid device name: %s\n", name);
+
+		/* Enable RTC block */
+		regmap_update_bits(regmap, RAA215300_REG_BLOCK_EN,
+				   RAA215300_REG_BLOCK_EN_RTC_EN,
+				   RAA215300_REG_BLOCK_EN_RTC_EN);
+
+		rtc_client = i2c_new_client_device(client->adapter, &info);
+		if (IS_ERR(rtc_client))
+			return PTR_ERR(rtc_client);
+
+		ret = devm_add_action_or_reset(dev,
+					       raa215300_rtc_unregister_device,
+					       rtc_client);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id raa215300_dt_match[] = {
+	{ .compatible = "renesas,raa215300" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, raa215300_dt_match);
+
+static struct i2c_driver raa215300_i2c_driver = {
+	.driver = {
+		.name = "raa215300",
+		.of_match_table = raa215300_dt_match,
+	},
+	.probe_new = raa215300_i2c_probe,
+};
+module_i2c_driver(raa215300_i2c_driver);
+
+MODULE_DESCRIPTION("Renesas RAA215300 PMIC driver");
+MODULE_AUTHOR("Fabrizio Castro <fabrizio.castro.jz@renesas.com>");
+MODULE_AUTHOR("Biju Das <biju.das.jz@bp.renesas.com>");
+MODULE_LICENSE("GPL");