1 /* 2 * TI/National Semiconductor LP3943 MFD Core Driver 3 * 4 * Copyright 2013 Texas Instruments 5 * 6 * Author: Milo Kim <milo.kim@ti.com> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 * 12 * Driver structure: 13 * LP3943 is an integrated device capable of driving 16 output channels. 14 * It can be used for a GPIO expander and PWM generators. 15 * 16 * LED control General usage for a device 17 * ___________ ____________________________ 18 * 19 * LP3943 MFD ---- GPIO expander leds-gpio eg) HW enable pin 20 * | 21 * --- PWM generator leds-pwm eg) PWM input 22 * 23 * Internal two PWM channels are used for LED dimming effect. 24 * And each output pin can be used as a GPIO as well. 25 * The LED functionality can work with GPIOs or PWMs. 26 * LEDs can be controlled with legacy leds-gpio(static brightness) or 27 * leds-pwm drivers(dynamic brightness control). 28 * Alternatively, it can be used for generic GPIO and PWM controller. 29 * For example, a GPIO is HW enable pin of a device. 30 * A PWM is input pin of a backlight device. 31 */ 32 33 #include <linux/err.h> 34 #include <linux/gpio.h> 35 #include <linux/i2c.h> 36 #include <linux/mfd/core.h> 37 #include <linux/mfd/lp3943.h> 38 #include <linux/module.h> 39 #include <linux/of.h> 40 #include <linux/slab.h> 41 42 #define LP3943_MAX_REGISTERS 0x09 43 44 /* Register configuration for pin MUX */ 45 static const struct lp3943_reg_cfg lp3943_mux_cfg[] = { 46 /* address, mask, shift */ 47 { LP3943_REG_MUX0, 0x03, 0 }, 48 { LP3943_REG_MUX0, 0x0C, 2 }, 49 { LP3943_REG_MUX0, 0x30, 4 }, 50 { LP3943_REG_MUX0, 0xC0, 6 }, 51 { LP3943_REG_MUX1, 0x03, 0 }, 52 { LP3943_REG_MUX1, 0x0C, 2 }, 53 { LP3943_REG_MUX1, 0x30, 4 }, 54 { LP3943_REG_MUX1, 0xC0, 6 }, 55 { LP3943_REG_MUX2, 0x03, 0 }, 56 { LP3943_REG_MUX2, 0x0C, 2 }, 57 { LP3943_REG_MUX2, 0x30, 4 }, 58 { LP3943_REG_MUX2, 0xC0, 6 }, 59 { LP3943_REG_MUX3, 0x03, 0 }, 60 { LP3943_REG_MUX3, 0x0C, 2 }, 61 { LP3943_REG_MUX3, 0x30, 4 }, 62 { LP3943_REG_MUX3, 0xC0, 6 }, 63 }; 64 65 static struct mfd_cell lp3943_devs[] = { 66 { 67 .name = "lp3943-pwm", 68 .of_compatible = "ti,lp3943-pwm", 69 }, 70 { 71 .name = "lp3943-gpio", 72 .of_compatible = "ti,lp3943-gpio", 73 }, 74 }; 75 76 int lp3943_read_byte(struct lp3943 *lp3943, u8 reg, u8 *read) 77 { 78 int ret; 79 unsigned int val; 80 81 ret = regmap_read(lp3943->regmap, reg, &val); 82 if (ret < 0) 83 return ret; 84 85 *read = (u8)val; 86 return 0; 87 } 88 EXPORT_SYMBOL_GPL(lp3943_read_byte); 89 90 int lp3943_write_byte(struct lp3943 *lp3943, u8 reg, u8 data) 91 { 92 return regmap_write(lp3943->regmap, reg, data); 93 } 94 EXPORT_SYMBOL_GPL(lp3943_write_byte); 95 96 int lp3943_update_bits(struct lp3943 *lp3943, u8 reg, u8 mask, u8 data) 97 { 98 return regmap_update_bits(lp3943->regmap, reg, mask, data); 99 } 100 EXPORT_SYMBOL_GPL(lp3943_update_bits); 101 102 static const struct regmap_config lp3943_regmap_config = { 103 .reg_bits = 8, 104 .val_bits = 8, 105 .max_register = LP3943_MAX_REGISTERS, 106 }; 107 108 static int lp3943_probe(struct i2c_client *cl, const struct i2c_device_id *id) 109 { 110 struct lp3943 *lp3943; 111 struct device *dev = &cl->dev; 112 113 lp3943 = devm_kzalloc(dev, sizeof(*lp3943), GFP_KERNEL); 114 if (!lp3943) 115 return -ENOMEM; 116 117 lp3943->regmap = devm_regmap_init_i2c(cl, &lp3943_regmap_config); 118 if (IS_ERR(lp3943->regmap)) 119 return PTR_ERR(lp3943->regmap); 120 121 lp3943->pdata = dev_get_platdata(dev); 122 lp3943->dev = dev; 123 lp3943->mux_cfg = lp3943_mux_cfg; 124 i2c_set_clientdata(cl, lp3943); 125 126 return mfd_add_devices(dev, -1, lp3943_devs, ARRAY_SIZE(lp3943_devs), 127 NULL, 0, NULL); 128 } 129 130 static int lp3943_remove(struct i2c_client *cl) 131 { 132 struct lp3943 *lp3943 = i2c_get_clientdata(cl); 133 134 mfd_remove_devices(lp3943->dev); 135 return 0; 136 } 137 138 static const struct i2c_device_id lp3943_ids[] = { 139 { "lp3943", 0 }, 140 { } 141 }; 142 MODULE_DEVICE_TABLE(i2c, lp3943_ids); 143 144 #ifdef CONFIG_OF 145 static const struct of_device_id lp3943_of_match[] = { 146 { .compatible = "ti,lp3943", }, 147 { } 148 }; 149 MODULE_DEVICE_TABLE(of, lp3943_of_match); 150 #endif 151 152 static struct i2c_driver lp3943_driver = { 153 .probe = lp3943_probe, 154 .remove = lp3943_remove, 155 .driver = { 156 .name = "lp3943", 157 .owner = THIS_MODULE, 158 .of_match_table = of_match_ptr(lp3943_of_match), 159 }, 160 .id_table = lp3943_ids, 161 }; 162 163 module_i2c_driver(lp3943_driver); 164 165 MODULE_DESCRIPTION("LP3943 MFD Core Driver"); 166 MODULE_AUTHOR("Milo Kim"); 167 MODULE_LICENSE("GPL"); 168