1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Driver for PCA9570 I2C GPO expander 4 * 5 * Copyright (C) 2020 Sungbo Eo <mans0n@gorani.run> 6 * 7 * Based on gpio-tpic2810.c 8 * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com/ 9 * Andrew F. Davis <afd@ti.com> 10 */ 11 12 #include <linux/gpio/driver.h> 13 #include <linux/i2c.h> 14 #include <linux/module.h> 15 #include <linux/mutex.h> 16 #include <linux/property.h> 17 18 /** 19 * struct pca9570 - GPIO driver data 20 * @chip: GPIO controller chip 21 * @lock: Protects write sequences 22 * @out: Buffer for device register 23 */ 24 struct pca9570 { 25 struct gpio_chip chip; 26 struct mutex lock; 27 u8 out; 28 }; 29 30 static int pca9570_read(struct pca9570 *gpio, u8 *value) 31 { 32 struct i2c_client *client = to_i2c_client(gpio->chip.parent); 33 int ret; 34 35 ret = i2c_smbus_read_byte(client); 36 if (ret < 0) 37 return ret; 38 39 *value = ret; 40 return 0; 41 } 42 43 static int pca9570_write(struct pca9570 *gpio, u8 value) 44 { 45 struct i2c_client *client = to_i2c_client(gpio->chip.parent); 46 47 return i2c_smbus_write_byte(client, value); 48 } 49 50 static int pca9570_get_direction(struct gpio_chip *chip, 51 unsigned offset) 52 { 53 /* This device always output */ 54 return GPIO_LINE_DIRECTION_OUT; 55 } 56 57 static int pca9570_get(struct gpio_chip *chip, unsigned offset) 58 { 59 struct pca9570 *gpio = gpiochip_get_data(chip); 60 u8 buffer; 61 int ret; 62 63 ret = pca9570_read(gpio, &buffer); 64 if (ret) 65 return ret; 66 67 return !!(buffer & BIT(offset)); 68 } 69 70 static void pca9570_set(struct gpio_chip *chip, unsigned offset, int value) 71 { 72 struct pca9570 *gpio = gpiochip_get_data(chip); 73 u8 buffer; 74 int ret; 75 76 mutex_lock(&gpio->lock); 77 78 buffer = gpio->out; 79 if (value) 80 buffer |= BIT(offset); 81 else 82 buffer &= ~BIT(offset); 83 84 ret = pca9570_write(gpio, buffer); 85 if (ret) 86 goto out; 87 88 gpio->out = buffer; 89 90 out: 91 mutex_unlock(&gpio->lock); 92 } 93 94 static int pca9570_probe(struct i2c_client *client) 95 { 96 struct pca9570 *gpio; 97 98 gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL); 99 if (!gpio) 100 return -ENOMEM; 101 102 gpio->chip.label = client->name; 103 gpio->chip.parent = &client->dev; 104 gpio->chip.owner = THIS_MODULE; 105 gpio->chip.get_direction = pca9570_get_direction; 106 gpio->chip.get = pca9570_get; 107 gpio->chip.set = pca9570_set; 108 gpio->chip.base = -1; 109 gpio->chip.ngpio = (uintptr_t)device_get_match_data(&client->dev); 110 gpio->chip.can_sleep = true; 111 112 mutex_init(&gpio->lock); 113 114 /* Read the current output level */ 115 pca9570_read(gpio, &gpio->out); 116 117 i2c_set_clientdata(client, gpio); 118 119 return devm_gpiochip_add_data(&client->dev, &gpio->chip, gpio); 120 } 121 122 static const struct i2c_device_id pca9570_id_table[] = { 123 { "pca9570", 4 }, 124 { "pca9571", 8 }, 125 { /* sentinel */ } 126 }; 127 MODULE_DEVICE_TABLE(i2c, pca9570_id_table); 128 129 static const struct of_device_id pca9570_of_match_table[] = { 130 { .compatible = "nxp,pca9570", .data = (void *)4 }, 131 { .compatible = "nxp,pca9571", .data = (void *)8 }, 132 { /* sentinel */ } 133 }; 134 MODULE_DEVICE_TABLE(of, pca9570_of_match_table); 135 136 static struct i2c_driver pca9570_driver = { 137 .driver = { 138 .name = "pca9570", 139 .of_match_table = pca9570_of_match_table, 140 }, 141 .probe_new = pca9570_probe, 142 .id_table = pca9570_id_table, 143 }; 144 module_i2c_driver(pca9570_driver); 145 146 MODULE_AUTHOR("Sungbo Eo <mans0n@gorani.run>"); 147 MODULE_DESCRIPTION("GPIO expander driver for PCA9570"); 148 MODULE_LICENSE("GPL v2"); 149