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| 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 | + |
| 27 | +static 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 | + |
| 42 | +static 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 | + |
| 47 | +static 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 | + |
| 52 | +static 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 | + |
| 60 | +static 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 | + |
| 90 | +static 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 | + |
| 120 | +static 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 | + |
| 154 | +static const struct of_device_id max7360_dt_match[] = { |
| 155 | + { .compatible = "maxim,max7360" }, |
| 156 | + {} |
| 157 | +}; |
| 158 | +MODULE_DEVICE_TABLE(of, max7360_dt_match); |
| 159 | + |
| 160 | +static struct i2c_driver max7360_driver = { |
| 161 | + .driver = { |
| 162 | + .name = "max7360", |
| 163 | + .of_match_table = max7360_dt_match, |
| 164 | + }, |
| 165 | + .probe = max7360_probe, |
| 166 | +}; |
| 167 | +module_i2c_driver(max7360_driver); |
| 168 | + |
| 169 | +MODULE_DESCRIPTION("Maxim MAX7360 I2C IO Expander core driver"); |
| 170 | +MODULE_AUTHOR("Kamel Bouhara <kamel.bouhara@bootlin.com>"); |
| 171 | +MODULE_LICENSE("GPL"); |
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