drivers/gpio/gpio-tps65219.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * GPIO driver for TI TPS65219 PMICs
   4  *
   5  * Copyright (C) 2022 Texas Instruments Incorporated - http://www.ti.com/
   6  */
   7
   8 #include <linux/bits.h>
   9 #include <linux/gpio/driver.h>
  10 #include <linux/mfd/tps65219.h>
  11 #include <linux/module.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/regmap.h>
  14
  15 #define TPS65219_GPIO0_DIR_MASK         BIT(3)
  16 #define TPS65219_GPIO0_OFFSET           2
  17 #define TPS65219_GPIO0_IDX              0
  18 #define TPS65219_GPIO_DIR_IN            1
  19 #define TPS65219_GPIO_DIR_OUT           0
  20
  21 struct tps65219_gpio {
  22         struct gpio_chip gpio_chip;
  23         struct tps65219 *tps;
  24 };
  25
  26 static int tps65219_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)
  27 {
  28         struct tps65219_gpio *gpio = gpiochip_get_data(gc);
  29         int ret, val;
  30
  31         if (offset != TPS65219_GPIO0_IDX)
  32                 return GPIO_LINE_DIRECTION_OUT;
  33
  34         ret = regmap_read(gpio->tps->regmap, TPS65219_REG_MFP_1_CONFIG, &val);
  35         if (ret)
  36                 return ret;
  37
  38         return !!(val & TPS65219_GPIO0_DIR_MASK);
  39 }
  40
  41 static int tps65219_gpio_get(struct gpio_chip *gc, unsigned int offset)
  42 {
  43         struct tps65219_gpio *gpio = gpiochip_get_data(gc);
  44         struct device *dev = gpio->tps->dev;
  45         int ret, val;
  46
  47         if (offset != TPS65219_GPIO0_IDX) {
  48                 dev_err(dev, "GPIO%d is output only, cannot get\n", offset);
  49                 return -ENOTSUPP;
  50         }
  51
  52         ret = regmap_read(gpio->tps->regmap, TPS65219_REG_MFP_CTRL, &val);
  53         if (ret)
  54                 return ret;
  55
  56         ret = !!(val & BIT(TPS65219_MFP_GPIO_STATUS_MASK));
  57         dev_warn(dev, "GPIO%d = %d, MULTI_DEVICE_ENABLE, not a standard GPIO\n", offset, ret);
  58
  59         /*
  60          * Depending on NVM config, return an error if direction is output, otherwise the GPIO0
  61          * status bit.
  62          */
  63
  64         if (tps65219_gpio_get_direction(gc, offset) == TPS65219_GPIO_DIR_OUT)
  65                 return -ENOTSUPP;
  66
  67         return ret;
  68 }
  69
  70 static void tps65219_gpio_set(struct gpio_chip *gc, unsigned int offset, int value)
  71 {
  72         struct tps65219_gpio *gpio = gpiochip_get_data(gc);
  73         struct device *dev = gpio->tps->dev;
  74         int v, mask, bit;
  75
  76         bit = (offset == TPS65219_GPIO0_IDX) ? TPS65219_GPIO0_OFFSET : offset - 1;
  77
  78         mask = BIT(bit);
  79         v = value ? mask : 0;
  80
  81         if (regmap_update_bits(gpio->tps->regmap, TPS65219_REG_GENERAL_CONFIG, mask, v))
  82                 dev_err(dev, "GPIO%d, set to value %d failed.\n", offset, value);
  83 }
  84
  85 static int tps65219_gpio_change_direction(struct gpio_chip *gc, unsigned int offset,
  86                                           unsigned int direction)
  87 {
  88         struct tps65219_gpio *gpio = gpiochip_get_data(gc);
  89         struct device *dev = gpio->tps->dev;
  90
  91         /*
  92          * Documentation is stating that GPIO0 direction must not be changed in Linux:
  93          * Table 8-34. MFP_1_CONFIG(3): MULTI_DEVICE_ENABLE, should only be changed in INITIALIZE
  94          * state (prior to ON Request).
  95          * Set statically by NVM, changing direction in application can cause a hang.
  96          * Below can be used for test purpose only.
  97          */
  98
  99 #if 0
 100         int ret = regmap_update_bits(gpio->tps->regmap, TPS65219_REG_MFP_1_CONFIG,
 101                                      TPS65219_GPIO0_DIR_MASK, direction);
 102         if (ret) {
 103                 dev_err(dev,
 104                         "GPIO DEBUG enabled: Fail to change direction to %u for GPIO%d.\n",
 105                         direction, offset);
 106                 return ret;
 107         }
 108 #endif
 109
 110         dev_err(dev,
 111                 "GPIO%d direction set by NVM, change to %u failed, not allowed by specification\n",
 112                  offset, direction);
 113
 114         return -ENOTSUPP;
 115 }
 116
 117 static int tps65219_gpio_direction_input(struct gpio_chip *gc, unsigned int offset)
 118 {
 119         struct tps65219_gpio *gpio = gpiochip_get_data(gc);
 120         struct device *dev = gpio->tps->dev;
 121
 122         if (offset != TPS65219_GPIO0_IDX) {
 123                 dev_err(dev, "GPIO%d is output only, cannot change to input\n", offset);
 124                 return -ENOTSUPP;
 125         }
 126
 127         if (tps65219_gpio_get_direction(gc, offset) == TPS65219_GPIO_DIR_IN)
 128                 return 0;
 129
 130         return tps65219_gpio_change_direction(gc, offset, TPS65219_GPIO_DIR_IN);
 131 }
 132
 133 static int tps65219_gpio_direction_output(struct gpio_chip *gc, unsigned int offset, int value)
 134 {
 135         tps65219_gpio_set(gc, offset, value);
 136         if (offset != TPS65219_GPIO0_IDX)
 137                 return 0;
 138
 139         if (tps65219_gpio_get_direction(gc, offset) == TPS65219_GPIO_DIR_OUT)
 140                 return 0;
 141
 142         return tps65219_gpio_change_direction(gc, offset, TPS65219_GPIO_DIR_OUT);
 143 }
 144
 145 static const struct gpio_chip tps65219_template_chip = {
 146         .label                  = "tps65219-gpio",
 147         .owner                  = THIS_MODULE,
 148         .get_direction          = tps65219_gpio_get_direction,
 149         .direction_input        = tps65219_gpio_direction_input,
 150         .direction_output       = tps65219_gpio_direction_output,
 151         .get                    = tps65219_gpio_get,
 152         .set                    = tps65219_gpio_set,
 153         .base                   = -1,
 154         .ngpio                  = 3,
 155         .can_sleep              = true,
 156 };
 157
 158 static int tps65219_gpio_probe(struct platform_device *pdev)
 159 {
 160         struct tps65219 *tps = dev_get_drvdata(pdev->dev.parent);
 161         struct tps65219_gpio *gpio;
 162
 163         gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
 164         if (!gpio)
 165                 return -ENOMEM;
 166
 167         gpio->tps = tps;
 168         gpio->gpio_chip = tps65219_template_chip;
 169         gpio->gpio_chip.parent = tps->dev;
 170
 171         return devm_gpiochip_add_data(&pdev->dev, &gpio->gpio_chip, gpio);
 172 }
 173
 174 static struct platform_driver tps65219_gpio_driver = {
 175         .driver = {
 176                 .name = "tps65219-gpio",
 177         },
 178         .probe = tps65219_gpio_probe,
 179 };
 180 module_platform_driver(tps65219_gpio_driver);
 181
 182 MODULE_ALIAS("platform:tps65219-gpio");
 183 MODULE_AUTHOR("Jonathan Cormier <jcormier@criticallink.com>");
 184 MODULE_DESCRIPTION("TPS65219 GPIO driver");
 185 MODULE_LICENSE("GPL");