drivers/gpio/gpio-lp873x.c

   1 /*
   2  * Copyright (C) 2016 Texas Instruments Incorporated - http://www.ti.com/
   3  *      Keerthy <j-keerthy@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  * Based on the TPS65218 driver
  15  */
  16
  17 #include <linux/gpio.h>
  18 #include <linux/module.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/regmap.h>
  21
  22 #include <linux/mfd/lp873x.h>
  23
  24 #define BITS_PER_GPO            0x4
  25 #define LP873X_GPO_CTRL_OD      0x2
  26
  27 struct lp873x_gpio {
  28         struct gpio_chip chip;
  29         struct lp873x *lp873;
  30 };
  31
  32 static int lp873x_gpio_get_direction(struct gpio_chip *chip,
  33                                      unsigned int offset)
  34 {
  35         /* This device is output only */
  36         return 0;
  37 }
  38
  39 static int lp873x_gpio_direction_input(struct gpio_chip *chip,
  40                                        unsigned int offset)
  41 {
  42         /* This device is output only */
  43         return -EINVAL;
  44 }
  45
  46 static int lp873x_gpio_direction_output(struct gpio_chip *chip,
  47                                         unsigned int offset, int value)
  48 {
  49         struct lp873x_gpio *gpio = gpiochip_get_data(chip);
  50
  51         /* Set the initial value */
  52         return regmap_update_bits(gpio->lp873->regmap, LP873X_REG_GPO_CTRL,
  53                                   BIT(offset * BITS_PER_GPO),
  54                                   value ? BIT(offset * BITS_PER_GPO) : 0);
  55 }
  56
  57 static int lp873x_gpio_get(struct gpio_chip *chip, unsigned int offset)
  58 {
  59         struct lp873x_gpio *gpio = gpiochip_get_data(chip);
  60         int ret, val;
  61
  62         ret = regmap_read(gpio->lp873->regmap, LP873X_REG_GPO_CTRL, &val);
  63         if (ret < 0)
  64                 return ret;
  65
  66         return val & BIT(offset * BITS_PER_GPO);
  67 }
  68
  69 static void lp873x_gpio_set(struct gpio_chip *chip, unsigned int offset,
  70                             int value)
  71 {
  72         struct lp873x_gpio *gpio = gpiochip_get_data(chip);
  73
  74         regmap_update_bits(gpio->lp873->regmap, LP873X_REG_GPO_CTRL,
  75                            BIT(offset * BITS_PER_GPO),
  76                            value ? BIT(offset * BITS_PER_GPO) : 0);
  77 }
  78
  79 static int lp873x_gpio_request(struct gpio_chip *gc, unsigned int offset)
  80 {
  81         struct lp873x_gpio *gpio = gpiochip_get_data(gc);
  82         int ret;
  83
  84         switch (offset) {
  85         case 0:
  86                 /* No MUX Set up Needed for GPO */
  87                 break;
  88         case 1:
  89                 /* Setup the CLKIN_PIN_SEL MUX to GPO2 */
  90                 ret = regmap_update_bits(gpio->lp873->regmap, LP873X_REG_CONFIG,
  91                                          LP873X_CONFIG_CLKIN_PIN_SEL, 0);
  92                 if (ret)
  93                         return ret;
  94
  95                 break;
  96         default:
  97                 return -EINVAL;
  98         }
  99
 100         return 0;
 101 }
 102
 103 static int lp873x_gpio_set_single_ended(struct gpio_chip *gc,
 104                                         unsigned int offset,
 105                                         enum single_ended_mode mode)
 106 {
 107         struct lp873x_gpio *gpio = gpiochip_get_data(gc);
 108
 109         switch (mode) {
 110         case LINE_MODE_OPEN_DRAIN:
 111                 return regmap_update_bits(gpio->lp873->regmap,
 112                                           LP873X_REG_GPO_CTRL,
 113                                           BIT(offset * BITS_PER_GPO +
 114                                           LP873X_GPO_CTRL_OD),
 115                                           BIT(offset * BITS_PER_GPO +
 116                                           LP873X_GPO_CTRL_OD));
 117         case LINE_MODE_PUSH_PULL:
 118                 return regmap_update_bits(gpio->lp873->regmap,
 119                                           LP873X_REG_GPO_CTRL,
 120                                           BIT(offset * BITS_PER_GPO +
 121                                           LP873X_GPO_CTRL_OD), 0);
 122         default:
 123                 return -ENOTSUPP;
 124         }
 125 }
 126
 127 static const struct gpio_chip template_chip = {
 128         .label                  = "lp873x-gpio",
 129         .owner                  = THIS_MODULE,
 130         .request                = lp873x_gpio_request,
 131         .get_direction          = lp873x_gpio_get_direction,
 132         .direction_input        = lp873x_gpio_direction_input,
 133         .direction_output       = lp873x_gpio_direction_output,
 134         .get                    = lp873x_gpio_get,
 135         .set                    = lp873x_gpio_set,
 136         .set_single_ended       = lp873x_gpio_set_single_ended,
 137         .base                   = -1,
 138         .ngpio                  = 2,
 139         .can_sleep              = true,
 140 };
 141
 142 static int lp873x_gpio_probe(struct platform_device *pdev)
 143 {
 144         struct lp873x_gpio *gpio;
 145         int ret;
 146
 147         gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
 148         if (!gpio)
 149                 return -ENOMEM;
 150
 151         platform_set_drvdata(pdev, gpio);
 152
 153         gpio->lp873 = dev_get_drvdata(pdev->dev.parent);
 154         gpio->chip = template_chip;
 155         gpio->chip.parent = gpio->lp873->dev;
 156
 157         ret = devm_gpiochip_add_data(&pdev->dev, &gpio->chip, gpio);
 158         if (ret < 0) {
 159                 dev_err(&pdev->dev, "Could not register gpiochip, %d\n", ret);
 160                 return ret;
 161         }
 162
 163         return 0;
 164 }
 165
 166 static const struct platform_device_id lp873x_gpio_id_table[] = {
 167         { "lp873x-gpio", },
 168         { /* sentinel */ }
 169 };
 170 MODULE_DEVICE_TABLE(platform, lp873x_gpio_id_table);
 171
 172 static struct platform_driver lp873x_gpio_driver = {
 173         .driver = {
 174                 .name = "lp873x-gpio",
 175         },
 176         .probe = lp873x_gpio_probe,
 177         .id_table = lp873x_gpio_id_table,
 178 };
 179 module_platform_driver(lp873x_gpio_driver);
 180
 181 MODULE_AUTHOR("Keerthy <j-keerthy@ti.com>");
 182 MODULE_DESCRIPTION("LP873X GPIO driver");
 183 MODULE_LICENSE("GPL v2");