drivers/mfd/lp3943.c

   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 const 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                 .of_match_table = of_match_ptr(lp3943_of_match),
 158         },
 159         .id_table = lp3943_ids,
 160 };
 161
 162 module_i2c_driver(lp3943_driver);
 163
 164 MODULE_DESCRIPTION("LP3943 MFD Core Driver");
 165 MODULE_AUTHOR("Milo Kim");
 166 MODULE_LICENSE("GPL");