max7360.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Maxim MAX7360 Core Driver
  4 *
  5 * Copyright 2025 Bootlin
  6 *
  7 * Authors:
  8 *    Kamel Bouhara <kamel.bouhara@bootlin.com>
  9 *    Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
 10 */
 11
 12#include <linux/array_size.h>
 13#include <linux/bits.h>
 14#include <linux/delay.h>
 15#include <linux/device/devres.h>
 16#include <linux/dev_printk.h>
 17#include <linux/err.h>
 18#include <linux/i2c.h>
 19#include <linux/interrupt.h>
 20#include <linux/mfd/core.h>
 21#include <linux/mfd/max7360.h>
 22#include <linux/mod_devicetable.h>
 23#include <linux/module.h>
 24#include <linux/regmap.h>
 25#include <linux/types.h>
 26
 27static const struct mfd_cell max7360_cells[] = {
 28	{ .name           = "max7360-pinctrl" },
 29	{ .name           = "max7360-pwm" },
 30	{ .name           = "max7360-keypad" },
 31	{ .name           = "max7360-rotary" },
 32	{
 33		.name           = "max7360-gpo",
 34		.of_compatible	= "maxim,max7360-gpo",
 35	},
 36	{
 37		.name           = "max7360-gpio",
 38		.of_compatible	= "maxim,max7360-gpio",
 39	},
 40};
 41
 42static const struct regmap_range max7360_volatile_ranges[] = {
 43	regmap_reg_range(MAX7360_REG_KEYFIFO, MAX7360_REG_KEYFIFO),
 44	regmap_reg_range(MAX7360_REG_I2C_TIMEOUT, MAX7360_REG_RTR_CNT),
 45};
 46
 47static const struct regmap_access_table max7360_volatile_table = {
 48	.yes_ranges = max7360_volatile_ranges,
 49	.n_yes_ranges = ARRAY_SIZE(max7360_volatile_ranges),
 50};
 51
 52static const struct regmap_config max7360_regmap_config = {
 53	.reg_bits = 8,
 54	.val_bits = 8,
 55	.max_register = MAX7360_REG_PWMCFG(MAX7360_PORT_PWM_COUNT - 1),
 56	.volatile_table = &max7360_volatile_table,
 57	.cache_type = REGCACHE_MAPLE,
 58};
 59
 60static int max7360_mask_irqs(struct regmap *regmap)
 61{
 62	struct device *dev = regmap_get_device(regmap);
 63	unsigned int val;
 64	int ret;
 65
 66	/*
 67	 * GPIO/PWM interrupts are not masked on reset: as the MAX7360 "INTI"
 68	 * interrupt line is shared between GPIOs and rotary encoder, this could
 69	 * result in repeated spurious interrupts on the rotary encoder driver
 70	 * if the GPIO driver is not loaded. Mask them now to avoid this
 71	 * situation.
 72	 */
 73	for (unsigned int i = 0; i < MAX7360_PORT_PWM_COUNT; i++) {
 74		ret = regmap_write_bits(regmap, MAX7360_REG_PWMCFG(i),
 75					MAX7360_PORT_CFG_INTERRUPT_MASK,
 76					MAX7360_PORT_CFG_INTERRUPT_MASK);
 77		if (ret)
 78			return dev_err_probe(dev, ret,
 79					     "Failed to write MAX7360 port configuration\n");
 80	}
 81
 82	/* Read GPIO in register, to ACK any pending IRQ. */
 83	ret = regmap_read(regmap, MAX7360_REG_GPIOIN, &val);
 84	if (ret)
 85		return dev_err_probe(dev, ret, "Failed to read GPIO values\n");
 86
 87	return 0;
 88}
 89
 90static int max7360_reset(struct regmap *regmap)
 91{
 92	struct device *dev = regmap_get_device(regmap);
 93	int ret;
 94
 95	ret = regmap_write(regmap, MAX7360_REG_GPIOCFG, MAX7360_GPIO_CFG_GPIO_RST);
 96	if (ret) {
 97		dev_err(dev, "Failed to reset GPIO configuration: %x\n", ret);
 98		return ret;
 99	}
100
101	ret = regcache_drop_region(regmap, MAX7360_REG_GPIOCFG, MAX7360_REG_GPIO_LAST);
102	if (ret) {
103		dev_err(dev, "Failed to drop regmap cache: %x\n", ret);
104		return ret;
105	}
106
107	ret = regmap_write(regmap, MAX7360_REG_SLEEP, 0);
108	if (ret) {
109		dev_err(dev, "Failed to reset autosleep configuration: %x\n", ret);
110		return ret;
111	}
112
113	ret = regmap_write(regmap, MAX7360_REG_DEBOUNCE, 0);
114	if (ret)
115		dev_err(dev, "Failed to reset GPO port count: %x\n", ret);
116
117	return ret;
118}
119
120static int max7360_probe(struct i2c_client *client)
121{
122	struct device *dev = &client->dev;
123	struct regmap *regmap;
124	int ret;
125
126	regmap = devm_regmap_init_i2c(client, &max7360_regmap_config);
127	if (IS_ERR(regmap))
128		return dev_err_probe(dev, PTR_ERR(regmap), "Failed to initialise regmap\n");
129
130	ret = max7360_reset(regmap);
131	if (ret)
132		return dev_err_probe(dev, ret, "Failed to reset device\n");
133
134	/* Get the device out of shutdown mode. */
135	ret = regmap_write_bits(regmap, MAX7360_REG_GPIOCFG,
136				MAX7360_GPIO_CFG_GPIO_EN,
137				MAX7360_GPIO_CFG_GPIO_EN);
138	if (ret)
139		return dev_err_probe(dev, ret, "Failed to enable GPIO and PWM module\n");
140
141	ret = max7360_mask_irqs(regmap);
142	if (ret)
143		return dev_err_probe(dev, ret, "Could not mask interrupts\n");
144
145	ret = devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE,
146				   max7360_cells, ARRAY_SIZE(max7360_cells),
147				   NULL, 0, NULL);
148	if (ret)
149		return dev_err_probe(dev, ret, "Failed to register child devices\n");
150
151	return 0;
152}
153
154static const struct of_device_id max7360_dt_match[] = {
155	{ .compatible = "maxim,max7360" },
156	{}
157};
158MODULE_DEVICE_TABLE(of, max7360_dt_match);
159
160static struct i2c_driver max7360_driver = {
161	.driver = {
162		.name = "max7360",
163		.of_match_table = max7360_dt_match,
164	},
165	.probe = max7360_probe,
166};
167module_i2c_driver(max7360_driver);
168
169MODULE_DESCRIPTION("Maxim MAX7360 I2C IO Expander core driver");
170MODULE_AUTHOR("Kamel Bouhara <kamel.bouhara@bootlin.com>");
171MODULE_LICENSE("GPL");