[PATCH v5 02/11] mfd: Add max7360 support

[mathieu.dubois-briand@bootlin.com]

From: Kamel Bouhara <kamel.bouhara@bootlin.com>

Add core driver to support MAX7360 i2c chip, multi function device
with keypad, GPIO, PWM, GPO and rotary encoder submodules.

Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
Co-developed-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
---
 drivers/mfd/Kconfig         |  14 ++++
 drivers/mfd/Makefile        |   1 +
 drivers/mfd/max7360.c       | 185 ++++++++++++++++++++++++++++++++++++++++++++
 include/linux/mfd/max7360.h | 112 +++++++++++++++++++++++++++
 4 files changed, 312 insertions(+)

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 6b0682af6e32..ef02a1c4322c 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -2439,5 +2439,19 @@ config MFD_UPBOARD_FPGA
 	  To compile this driver as a module, choose M here: the module will be
 	  called upboard-fpga.
 
+config MFD_MAX7360
+	tristate "Maxim MAX7360 I2C IO Expander"
+	depends on I2C
+	select MFD_CORE
+	select REGMAP_I2C
+	select REGMAP_IRQ
+	help
+	  Say yes here to add support for Maxim MAX7360 device, embedding
+	  keypad, rotary encoder, PWM and GPIO features.
+
+	  This driver provides common support for accessing the device;
+	  additional drivers must be enabled in order to use the functionality
+	  of the device.
+
 endmenu
 endif
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 9220eaf7cf12..db2bd232c150 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -163,6 +163,7 @@ obj-$(CONFIG_MFD_DA9063)	+= da9063.o
 obj-$(CONFIG_MFD_DA9150)	+= da9150-core.o
 
 obj-$(CONFIG_MFD_MAX14577)	+= max14577.o
+obj-$(CONFIG_MFD_MAX7360)	+= max7360.o
 obj-$(CONFIG_MFD_MAX77541)	+= max77541.o
 obj-$(CONFIG_MFD_MAX77620)	+= max77620.o
 obj-$(CONFIG_MFD_MAX77650)	+= max77650.o
diff --git a/drivers/mfd/max7360.c b/drivers/mfd/max7360.c
new file mode 100644
index 000000000000..9f489a798f94
--- /dev/null
+++ b/drivers/mfd/max7360.c
@@ -0,0 +1,185 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Maxim MAX7360 Core Driver
+ *
+ * Copyright 2025 Bootlin
+ *
+ * Author: Kamel Bouhara <kamel.bouhara@bootlin.com>
+ * Author: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
+ */
+
+#include <linux/bits.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/max7360.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/types.h>
+
+static const struct mfd_cell max7360_cells[] = {
+	{
+		.name           = "max7360-pinctrl",
+	},
+	{
+		.name           = "max7360-pwm",
+	},
+	{
+		.name           = "max7360-gpo",
+		.of_compatible	= "maxim,max7360-gpo",
+	},
+	{
+		.name           = "max7360-gpio",
+		.of_compatible	= "maxim,max7360-gpio",
+	},
+	{
+		.name           = "max7360-keypad",
+	},
+	{
+		.name           = "max7360-rotary",
+	},
+};
+
+static const struct regmap_range max7360_volatile_ranges[] = {
+	{
+		.range_min = MAX7360_REG_KEYFIFO,
+		.range_max = MAX7360_REG_KEYFIFO,
+	}, {
+		.range_min = MAX7360_REG_I2C_TIMEOUT,
+		.range_max = MAX7360_REG_RTR_CNT,
+	},
+};
+
+static const struct regmap_access_table max7360_volatile_table = {
+	.yes_ranges = max7360_volatile_ranges,
+	.n_yes_ranges = ARRAY_SIZE(max7360_volatile_ranges),
+};
+
+static const struct regmap_config max7360_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = MAX7360_REG_PWMCFG(MAX7360_PORT_PWM_COUNT - 1),
+	.volatile_table = &max7360_volatile_table,
+	.cache_type = REGCACHE_MAPLE,
+};
+
+static int max7360_mask_irqs(struct regmap *regmap)
+{
+	struct device *dev = regmap_get_device(regmap);
+	unsigned int val;
+	int ret;
+
+	/*
+	 * GPIO/PWM interrupts are not masked on reset: mask the during probe,
+	 * avoiding repeated spurious interrupts if the corresponding drivers
+	 * are not present.
+	 */
+	for (unsigned int i = 0; i < MAX7360_PORT_PWM_COUNT; i++) {
+		ret = regmap_write_bits(regmap, MAX7360_REG_PWMCFG(i),
+					MAX7360_PORT_CFG_INTERRUPT_MASK,
+					MAX7360_PORT_CFG_INTERRUPT_MASK);
+		if (ret) {
+			dev_err(dev, "Failed to write max7360 port configuration");
+			return ret;
+		}
+	}
+
+	/* Read GPIO in register, to ACK any pending IRQ. */
+	ret = regmap_read(regmap, MAX7360_REG_GPIOIN, &val);
+	if (ret)
+		dev_err(dev, "Failed to read gpio values: %d\n", ret);
+
+	return ret;
+}
+
+static int max7360_reset(struct regmap *regmap)
+{
+	struct device *dev = regmap_get_device(regmap);
+	int ret;
+
+	ret = regmap_write(regmap, MAX7360_REG_GPIOCFG,
+			   MAX7360_GPIO_CFG_GPIO_RST);
+	if (ret) {
+		dev_err(dev, "Failed to reset GPIO configuration: %x\n", ret);
+		return ret;
+	}
+
+	ret = regcache_drop_region(regmap, MAX7360_REG_GPIOCFG,
+				   MAX7360_REG_GPIO_LAST);
+	if (ret) {
+		dev_err(dev, "Failed to drop regmap cache: %x\n", ret);
+		return ret;
+	}
+
+	ret = regmap_write(regmap, MAX7360_REG_SLEEP, 0);
+	if (ret) {
+		dev_err(dev, "Failed to reset autosleep configuration: %x\n", ret);
+		return ret;
+	}
+
+	ret = regmap_write(regmap, MAX7360_REG_DEBOUNCE, 0);
+	if (ret) {
+		dev_err(dev, "Failed to reset GPO port count: %x\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int max7360_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct regmap *regmap;
+	int ret;
+
+	regmap = devm_regmap_init_i2c(client, &max7360_regmap_config);
+	if (IS_ERR(regmap))
+		return dev_err_probe(dev, PTR_ERR(regmap),
+				     "Failed to initialise regmap\n");
+
+	i2c_set_clientdata(client, regmap);
+
+	ret = max7360_reset(regmap);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to reset device\n");
+
+	/* Get the device out of shutdown mode. */
+	ret = regmap_write_bits(regmap, MAX7360_REG_GPIOCFG,
+				MAX7360_GPIO_CFG_GPIO_EN,
+				MAX7360_GPIO_CFG_GPIO_EN);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to enable GPIO and PWM module\n");
+
+	ret = max7360_mask_irqs(regmap);
+	if (ret)
+		return dev_err_probe(dev, ret, "Could not mask interrupts\n");
+
+	ret =  devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE,
+				    max7360_cells, ARRAY_SIZE(max7360_cells),
+				    NULL, 0, NULL);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to register child devices\n");
+
+	return 0;
+}
+
+static const struct of_device_id max7360_dt_match[] = {
+	{ .compatible = "maxim,max7360" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, max7360_dt_match);
+
+static struct i2c_driver max7360_driver = {
+	.driver = {
+		.name = "max7360",
+		.of_match_table = max7360_dt_match,
+	},
+	.probe = max7360_probe,
+};
+module_i2c_driver(max7360_driver);
+
+MODULE_DESCRIPTION("Maxim MAX7360 I2C IO Expander core driver");
+MODULE_AUTHOR("Kamel Bouhara <kamel.bouhara@bootlin.com>");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/mfd/max7360.h b/include/linux/mfd/max7360.h
new file mode 100644
index 000000000000..c5a90fa5b76b
--- /dev/null
+++ b/include/linux/mfd/max7360.h
@@ -0,0 +1,112 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __LINUX_MFD_MAX7360_H
+#define __LINUX_MFD_MAX7360_H
+
+#include <linux/bits.h>
+#include <linux/types.h>
+
+struct device;
+
+#define MAX7360_MAX_KEY_ROWS		8
+#define MAX7360_MAX_KEY_COLS		8
+#define MAX7360_MAX_KEY_NUM		(MAX7360_MAX_KEY_ROWS * MAX7360_MAX_KEY_COLS)
+#define MAX7360_ROW_SHIFT		3
+
+#define MAX7360_MAX_GPIO		8
+#define MAX7360_MAX_GPO			6
+#define MAX7360_PORT_PWM_COUNT		8
+#define MAX7360_PORT_RTR_PIN		(MAX7360_PORT_PWM_COUNT - 1)
+
+/*
+ * MAX7360 registers
+ */
+#define MAX7360_REG_KEYFIFO		0x00
+#define MAX7360_REG_CONFIG		0x01
+#define MAX7360_REG_DEBOUNCE		0x02
+#define MAX7360_REG_INTERRUPT		0x03
+#define MAX7360_REG_PORTS		0x04
+#define MAX7360_REG_KEYREP		0x05
+#define MAX7360_REG_SLEEP		0x06
+
+/*
+ * MAX7360 GPIO registers
+ *
+ * All these registers are reset together when writing bit 3 of
+ * MAX7360_REG_GPIOCFG.
+ */
+#define MAX7360_REG_GPIOCFG		0x40
+#define MAX7360_REG_GPIOCTRL		0x41
+#define MAX7360_REG_GPIODEB		0x42
+#define MAX7360_REG_GPIOCURR		0x43
+#define MAX7360_REG_GPIOOUTM		0x44
+#define MAX7360_REG_PWMCOM		0x45
+#define MAX7360_REG_RTRCFG		0x46
+#define MAX7360_REG_I2C_TIMEOUT		0x48
+#define MAX7360_REG_GPIOIN		0x49
+#define MAX7360_REG_RTR_CNT		0x4A
+#define MAX7360_REG_PWMBASE		0x50
+#define MAX7360_REG_PWMCFGBASE		0x58
+
+#define MAX7360_REG_GPIO_LAST		0x5F
+
+#define MAX7360_REG_PWM(x)		(MAX7360_REG_PWMBASE + (x))
+#define MAX7360_REG_PWMCFG(x)		(MAX7360_REG_PWMCFGBASE + (x))
+
+/*
+ * Configuration register bits
+ */
+#define MAX7360_FIFO_EMPTY		0x3f
+#define MAX7360_FIFO_OVERFLOW		0x7f
+#define MAX7360_FIFO_RELEASE		BIT(6)
+#define MAX7360_FIFO_COL		GENMASK(5, 3)
+#define MAX7360_FIFO_ROW		GENMASK(2, 0)
+
+#define MAX7360_CFG_SLEEP		BIT(7)
+#define MAX7360_CFG_INTERRUPT		BIT(5)
+#define MAX7360_CFG_KEY_RELEASE		BIT(3)
+#define MAX7360_CFG_WAKEUP		BIT(1)
+#define MAX7360_CFG_TIMEOUT		BIT(0)
+
+#define MAX7360_DEBOUNCE		GENMASK(4, 0)
+#define MAX7360_DEBOUNCE_MIN		9
+#define MAX7360_DEBOUNCE_MAX		40
+#define MAX7360_PORTS			GENMASK(8, 5)
+
+#define MAX7360_INTERRUPT_TIME_MASK	GENMASK(4, 0)
+#define MAX7360_INTERRUPT_FIFO_MASK	GENMASK(7, 5)
+
+#define MAX7360_PORT_CFG_INTERRUPT_MASK		BIT(7)
+#define MAX7360_PORT_CFG_INTERRUPT_EDGES	BIT(6)
+#define MAX7360_PORT_CFG_COMMON_PWM		BIT(5)
+
+/*
+ * Autosleep register values
+ */
+#define MAX7360_AUTOSLEEP_8192MS	0x01
+#define MAX7360_AUTOSLEEP_4096MS	0x02
+#define MAX7360_AUTOSLEEP_2048MS	0x03
+#define MAX7360_AUTOSLEEP_1024MS	0x04
+#define MAX7360_AUTOSLEEP_512MS		0x05
+#define MAX7360_AUTOSLEEP_256MS		0x06
+
+#define MAX7360_GPIO_CFG_RTR_EN		BIT(7)
+#define MAX7360_GPIO_CFG_GPIO_EN	BIT(4)
+#define MAX7360_GPIO_CFG_GPIO_RST	BIT(3)
+
+#define MAX7360_ROT_DEBOUNCE		GENMASK(3, 0)
+#define MAX7360_ROT_DEBOUNCE_MIN	0
+#define MAX7360_ROT_DEBOUNCE_MAX	15
+#define MAX7360_ROT_INTCNT		GENMASK(6, 4)
+#define MAX7360_ROT_INTCNT_DLY		BIT(7)
+
+#define MAX7360_INT_INTI		0
+#define MAX7360_INT_INTK		1
+
+#define MAX7360_INT_GPIO		0
+#define MAX7360_INT_KEYPAD		1
+#define MAX7360_INT_ROTARY		2
+
+#define MAX7360_NR_INTERNAL_IRQS	3
+
+#endif

-- 
2.39.5