[PATCH v3 2/2] mfd: max597x: Add support for MAX5970 and MAX5978

From: Naresh Solanki
Date: Mon Oct 31 2022 - 16:42:07 EST

From: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>

Implement a regulator driver with IRQ support for fault management.
Written against documentation [1] and [2] and tested on real hardware.

Every channel has its own regulator supplies nammed 'vss1-supply' and
'vss2-supply'. The regulator supply is used to determine the output
voltage, as the smart switch provides no output regulation.
The driver requires the 'shunt-resistor-micro-ohms' property to be
present in Device Tree to properly calculate current related
values.

Datasheet links:
1: https://datasheets.maximintegrated.com/en/ds/MAX5970.pdf
2: https://datasheets.maximintegrated.com/en/ds/MAX5978.pdf

Signed-off-by: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>
Signed-off-by: Marcello Sylvester Bauer <sylv@xxxxxxx>
Signed-off-by: Naresh Solanki <Naresh.Solanki@xxxxxxxxxxxxx>
---
drivers/mfd/Kconfig | 12 +++++
drivers/mfd/Makefile | 1 +
drivers/mfd/max597x.c | 87 ++++++++++++++++++++++++++++++
include/linux/mfd/max597x.h | 102 ++++++++++++++++++++++++++++++++++++
4 files changed, 202 insertions(+)
create mode 100644 drivers/mfd/max597x.c
create mode 100644 include/linux/mfd/max597x.h

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 8b93856de432..416fe7986b7b 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -253,6 +253,18 @@ config MFD_MADERA_SPI
Support for the Cirrus Logic Madera platform audio SoC
core functionality controlled via SPI.

+config MFD_MAX597X
+ tristate "Maxim 597x Power Switch and Monitor"
+ depends on I2C
+ depends on OF
+ select MFD_CORE
+ select REGMAP_I2C
+ help
+ This driver controls a Maxim 5970/5978 switch via I2C bus.
+ The MAX5970/5978 is a smart switch with no output regulation, but
+ fault protection and voltage and current monitoring capabilities.
+ Also it supports upto 4 indication LEDs.
+
config MFD_CS47L15
bool "Cirrus Logic CS47L15"
select PINCTRL_CS47L15
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 7ed3ef4a698c..819d711fa748 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -161,6 +161,7 @@ obj-$(CONFIG_MFD_DA9063) += da9063.o
obj-$(CONFIG_MFD_DA9150) += da9150-core.o

obj-$(CONFIG_MFD_MAX14577) += max14577.o
+obj-$(CONFIG_MFD_MAX597X) += max597x.o
obj-$(CONFIG_MFD_MAX77620) += max77620.o
obj-$(CONFIG_MFD_MAX77650) += max77650.o
obj-$(CONFIG_MFD_MAX77686) += max77686.o
diff --git a/drivers/mfd/max597x.c b/drivers/mfd/max597x.c
new file mode 100644
index 000000000000..68a4e7755f21
--- /dev/null
+++ b/drivers/mfd/max597x.c
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Maxim MAX5970/MAX5978 MFD Driver
+ *
+ * Copyright (c) 2022 9elements GmbH
+ *
+ * Author: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>
+ */
+
+#include <linux/i2c.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/max597x.h>
+#include <linux/regmap.h>
+
+static const struct regmap_config max597x_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .max_register = MAX_REGISTERS,
+};
+
+static const struct mfd_cell max597x_cells[] = {
+ { .name = "max597x-regulator", },
+ { .name = "max597x-iio", },
+ { .name = "max597x-led", },
+};
+
+static int max597x_probe(struct i2c_client *i2c, const struct i2c_device_id *id)
+{
+ struct max597x_data *ddata;
+ enum max597x_chip_type chip = id->driver_data;
+
+ ddata = devm_kzalloc(&i2c->dev, sizeof(*ddata),
+ GFP_KERNEL);
+
+ switch (chip) {
+ case MAX597x_TYPE_MAX5970:
+ ddata->num_switches = 2;
+ break;
+ case MAX597x_TYPE_MAX5978:
+ ddata->num_switches = 1;
+ break;
+ }
+
+ ddata->regmap = devm_regmap_init_i2c(i2c, &max597x_regmap_config);
+ if (IS_ERR(ddata->regmap)) {
+ dev_err(&i2c->dev, "Failed to initialise regmap");
+ return -EINVAL;
+ }
+
+ /* IRQ used by regulator cell */
+ ddata->irq = i2c->irq;
+ ddata->dev = &i2c->dev;
+ i2c_set_clientdata(i2c, ddata);
+
+ return devm_mfd_add_devices(ddata->dev, PLATFORM_DEVID_AUTO,
+ max597x_cells, ARRAY_SIZE(max597x_cells),
+ NULL, 0, NULL);
+}
+
+static const struct i2c_device_id max597x_table[] = {
+ { .name = "max5970", MAX597x_TYPE_MAX5970 },
+ { .name = "max5978", MAX597x_TYPE_MAX5978 },
+};
+
+MODULE_DEVICE_TABLE(i2c, max597x_table);
+
+static const struct of_device_id max597x_of_match[] = {
+ { .compatible = "maxim,max5970", .data = (void *)MAX597x_TYPE_MAX5970 },
+ { .compatible = "maxim,max5978", .data = (void *)MAX597x_TYPE_MAX5978 },
+};
+
+MODULE_DEVICE_TABLE(of, max597x_of_match);
+
+static struct i2c_driver max597x_driver = {
+ .id_table = max597x_table,
+ .driver = {
+ .name = "max597x",
+ .of_match_table = of_match_ptr(max597x_of_match),
+ },
+ .probe = max597x_probe,
+};
+
+module_i2c_driver(max597x_driver);
+
+MODULE_AUTHOR("Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("MAX597X Power Switch and Monitor");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/mfd/max597x.h b/include/linux/mfd/max597x.h
new file mode 100644
index 000000000000..ae7f38f0aee2
--- /dev/null
+++ b/include/linux/mfd/max597x.h
@@ -0,0 +1,102 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Maxim MAX5970/MAX5978 MFD Driver
+ *
+ * Copyright (c) 2022 9elements GmbH
+ *
+ * Author: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>
+ */
+
+#ifndef MFD_MAX597X_H
+#define MFD_MAX597X_H
+
+#include <linux/device.h>
+#include <linux/regmap.h>
+
+#define MAX5970_NUM_SWITCHES 2
+#define MAX5978_NUM_SWITCHES 1
+#define MAX597X_NUM_LEDS 4
+
+enum max597x_chip_type {
+ MAX597x_TYPE_MAX5978 = 1,
+ MAX597x_TYPE_MAX5970,
+};
+
+#define MAX5970_REG_CURRENT_L(ch) (0x01 + (ch) * 4)
+#define MAX5970_REG_CURRENT_H(ch) (0x00 + (ch) * 4)
+#define MAX5970_REG_VOLTAGE_L(ch) (0x03 + (ch) * 4)
+#define MAX5970_REG_VOLTAGE_H(ch) (0x02 + (ch) * 4)
+#define MAX5970_REG_MON_RANGE 0x18
+#define MAX5970_MON_MASK 0x3
+#define MAX5970_MON(reg, ch) \
+ (((reg) >> ((ch) * 2)) & MAX5970_MON_MASK)
+#define MAX5970_MON_MAX_RANGE_UV 16000000
+
+#define MAX5970_REG_CH_UV_WARN_H(ch) (0x1A + (ch) * 10)
+#define MAX5970_REG_CH_UV_WARN_L(ch) (0x1B + (ch) * 10)
+#define MAX5970_REG_CH_UV_CRIT_H(ch) (0x1C + (ch) * 10)
+#define MAX5970_REG_CH_UV_CRIT_L(ch) (0x1D + (ch) * 10)
+#define MAX5970_REG_CH_OV_WARN_H(ch) (0x1E + (ch) * 10)
+#define MAX5970_REG_CH_OV_WARN_L(ch) (0x1F + (ch) * 10)
+#define MAX5970_REG_CH_OV_CRIT_H(ch) (0x20 + (ch) * 10)
+#define MAX5970_REG_CH_OV_CRIT_L(ch) (0x21 + (ch) * 10)
+
+#define MAX5970_VAL2REG_H(x) (((x) >> 2) & 0xFF)
+#define MAX5970_VAL2REG_L(x) ((x) & 0x3)
+
+#define MAX5970_REG_DAC_FAST(ch) (0x2E + (ch))
+
+#define MAX5970_FAST2SLOW_RATIO 200
+
+#define MAX5970_REG_STATUS0 0x31
+#define MAX5970_CB_IFAULTF(ch) (1 << (ch))
+#define MAX5970_CB_IFAULTS(ch) (1 << ((ch) + 4))
+
+#define MAX5970_REG_STATUS1 0x32
+#define STATUS1_PROT_MASK 0x3
+#define STATUS1_PROT(reg) \
+ (((reg) >> 6) & STATUS1_PROT_MASK)
+#define STATUS1_PROT_SHUTDOWN 0
+#define STATUS1_PROT_CLEAR_PG 1
+#define STATUS1_PROT_ALERT_ONLY 2
+
+#define MAX5970_REG_STATUS2 0x33
+#define MAX5970_IRNG_MASK 0x3
+#define MAX5970_IRNG(reg, ch) \
+ (((reg) >> ((ch) * 2)) & MAX5970_IRNG_MASK)
+
+#define MAX5970_REG_STATUS3 0x34
+#define MAX5970_STATUS3_ALERT BIT(4)
+#define MAX5970_STATUS3_PG(ch) BIT(ch)
+
+#define MAX5970_REG_FAULT0 0x35
+#define UV_STATUS_WARN(ch) BIT(ch)
+#define UV_STATUS_CRIT(ch) BIT(ch + 4)
+
+#define MAX5970_REG_FAULT1 0x36
+#define OV_STATUS_WARN(ch) BIT(ch)
+#define OV_STATUS_CRIT(ch) BIT(ch + 4)
+
+#define MAX5970_REG_FAULT2 0x37
+#define OC_STATUS_WARN(ch) BIT(ch)
+
+#define MAX5970_REG_CHXEN 0x3b
+#define CHXEN(ch) (3 << (ch * 2))
+
+#define MAX5970_REG_LED_FLASH 0x43
+
+#define MAX_REGISTERS 0x49
+#define ADC_MASK 0x3FF
+
+struct max597x_data {
+ struct device *dev;
+ int irq;
+ int num_switches;
+ struct regmap *regmap;
+ /* Chip specific parameters needed by regulator & iio cells */
+ u32 irng[MAX5970_NUM_SWITCHES];
+ u32 mon_rng[MAX5970_NUM_SWITCHES];
+ u32 shunt_micro_ohms[MAX5970_NUM_SWITCHES];
+};
+
+#endif /* _MAX597X_H */
--
2.37.3