1 /* 2 * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com/ 3 * Andrew F. Davis <afd@ti.com> 4 * 5 * This program is free software; you can redistribute it and/or 6 * modify it under the terms of the GNU General Public License version 2 as 7 * published by the Free Software Foundation. 8 * 9 * This program is distributed "as is" WITHOUT ANY WARRANTY of any 10 * kind, whether expressed or implied; without even the implied warranty 11 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License version 2 for more details. 13 */ 14 15 #include <linux/gpio/driver.h> 16 #include <linux/i2c.h> 17 #include <linux/module.h> 18 #include <linux/mutex.h> 19 20 #define TPIC2810_WS_COMMAND 0x44 21 22 /** 23 * struct tpic2810 - GPIO driver data 24 * @chip: GPIO controller chip 25 * @client: I2C device pointer 26 * @buffer: Buffer for device register 27 * @lock: Protects write sequences 28 */ 29 struct tpic2810 { 30 struct gpio_chip chip; 31 struct i2c_client *client; 32 u8 buffer; 33 struct mutex lock; 34 }; 35 36 static void tpic2810_set(struct gpio_chip *chip, unsigned offset, int value); 37 38 static int tpic2810_get_direction(struct gpio_chip *chip, 39 unsigned offset) 40 { 41 /* This device always output */ 42 return 0; 43 } 44 45 static int tpic2810_direction_input(struct gpio_chip *chip, 46 unsigned offset) 47 { 48 /* This device is output only */ 49 return -EINVAL; 50 } 51 52 static int tpic2810_direction_output(struct gpio_chip *chip, 53 unsigned offset, int value) 54 { 55 /* This device always output */ 56 tpic2810_set(chip, offset, value); 57 return 0; 58 } 59 60 static void tpic2810_set_mask_bits(struct gpio_chip *chip, u8 mask, u8 bits) 61 { 62 struct tpic2810 *gpio = gpiochip_get_data(chip); 63 u8 buffer; 64 int err; 65 66 mutex_lock(&gpio->lock); 67 68 buffer = gpio->buffer & ~mask; 69 buffer |= (mask & bits); 70 71 err = i2c_smbus_write_byte_data(gpio->client, TPIC2810_WS_COMMAND, 72 buffer); 73 if (!err) 74 gpio->buffer = buffer; 75 76 mutex_unlock(&gpio->lock); 77 } 78 79 static void tpic2810_set(struct gpio_chip *chip, unsigned offset, int value) 80 { 81 tpic2810_set_mask_bits(chip, BIT(offset), value ? BIT(offset) : 0); 82 } 83 84 static void tpic2810_set_multiple(struct gpio_chip *chip, unsigned long *mask, 85 unsigned long *bits) 86 { 87 tpic2810_set_mask_bits(chip, *mask, *bits); 88 } 89 90 static const struct gpio_chip template_chip = { 91 .label = "tpic2810", 92 .owner = THIS_MODULE, 93 .get_direction = tpic2810_get_direction, 94 .direction_input = tpic2810_direction_input, 95 .direction_output = tpic2810_direction_output, 96 .set = tpic2810_set, 97 .set_multiple = tpic2810_set_multiple, 98 .base = -1, 99 .ngpio = 8, 100 .can_sleep = true, 101 }; 102 103 static const struct of_device_id tpic2810_of_match_table[] = { 104 { .compatible = "ti,tpic2810" }, 105 { /* sentinel */ } 106 }; 107 MODULE_DEVICE_TABLE(of, tpic2810_of_match_table); 108 109 static int tpic2810_probe(struct i2c_client *client, 110 const struct i2c_device_id *id) 111 { 112 struct tpic2810 *gpio; 113 int ret; 114 115 gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL); 116 if (!gpio) 117 return -ENOMEM; 118 119 i2c_set_clientdata(client, gpio); 120 121 gpio->chip = template_chip; 122 gpio->chip.parent = &client->dev; 123 124 gpio->client = client; 125 126 mutex_init(&gpio->lock); 127 128 ret = gpiochip_add_data(&gpio->chip, gpio); 129 if (ret < 0) { 130 dev_err(&client->dev, "Unable to register gpiochip\n"); 131 return ret; 132 } 133 134 return 0; 135 } 136 137 static int tpic2810_remove(struct i2c_client *client) 138 { 139 struct tpic2810 *gpio = i2c_get_clientdata(client); 140 141 gpiochip_remove(&gpio->chip); 142 143 return 0; 144 } 145 146 static const struct i2c_device_id tpic2810_id_table[] = { 147 { "tpic2810", }, 148 { /* sentinel */ } 149 }; 150 MODULE_DEVICE_TABLE(i2c, tpic2810_id_table); 151 152 static struct i2c_driver tpic2810_driver = { 153 .driver = { 154 .name = "tpic2810", 155 .of_match_table = tpic2810_of_match_table, 156 }, 157 .probe = tpic2810_probe, 158 .remove = tpic2810_remove, 159 .id_table = tpic2810_id_table, 160 }; 161 module_i2c_driver(tpic2810_driver); 162 163 MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>"); 164 MODULE_DESCRIPTION("TPIC2810 8-Bit LED Driver GPIO Driver"); 165 MODULE_LICENSE("GPL v2"); 166