[PATCH v14 02/10] mfd: Add max7360 support

Mathieu Dubois-Briand
2025-08-24T11:57:56Z

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>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
drivers/mfd/Kconfig | 14 ++++
drivers/mfd/Makefile | 1 +
drivers/mfd/max7360.c | 171 ++++++++++++++++++++++++++++++++++++++++++++
include/linux/mfd/max7360.h | 109 ++++++++++++++++++++++++++++
4 files changed, 295 insertions(+)

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 425c5fba6cb1..58b1c2900d59 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -2481,5 +2481,19 @@ 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 f7bdedd5a66d..c81c6a8473e1 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..5ee459c490ec
--- /dev/null
+++ b/drivers/mfd/max7360.c
@@ -0,0 +1,171 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Maxim MAX7360 Core Driver
+ *
+ * Copyright 2025 Bootlin
+ *
+ * Authors:
+ * Kamel Bouhara <kamel.bouhara@bootlin.com>
+ * Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
+ */
+
+#include <linux/array_size.h>
+#include <linux/bits.h>
+#include <linux/delay.h>
+#include <linux/device/devres.h>
+#include <linux/dev_printk.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/max7360.h>
+#include <linux/mod_devicetable.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-keypad" },
+ { .name = "max7360-rotary" },
+ {
+ .name = "max7360-gpo",
+ .of_compatible = "maxim,max7360-gpo",
+ },
+ {
+ .name = "max7360-gpio",
+ .of_compatible = "maxim,max7360-gpio",
+ },
+};
+
+static const struct regmap_range max7360_volatile_ranges[] = {
+ regmap_reg_range(MAX7360_REG_KEYFIFO, MAX7360_REG_KEYFIFO),
+ regmap_reg_range(MAX7360_REG_I2C_TIMEOUT, 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: as the MAX7360 "INTI"
+ * interrupt line is shared between GPIOs and rotary encoder, this could
+ * result in repeated spurious interrupts on the rotary encoder driver
+ * if the GPIO driver is not loaded. Mask them now to avoid this
+ * situation.
+ */
+ 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)
+ return dev_err_probe(dev, ret,
+ "Failed to write MAX7360 port configuration\n");
+ }
+
+ /* Read GPIO in register, to ACK any pending IRQ. */
+ ret = regmap_read(regmap, MAX7360_REG_GPIOIN, &val);
+ if (ret)
+ return dev_err_probe(dev, ret, "Failed to read GPIO values\n");
+
+ return 0;
+}
+
+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;
+}
+
+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");
+
+ 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..44cf2bf651a2
--- /dev/null
+++ b/include/linux/mfd/max7360.h
@@ -0,0 +1,109 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __LINUX_MFD_MAX7360_H
+#define __LINUX_MFD_MAX7360_H
+
+#include <linux/bits.h>
+
+#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