drivers/gpio/bcm2835_gpio.c

   1 /*
   2  * Copyright (C) 2012 Vikram Narayananan
   3  * <vikram186@gmail.com>
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 #include <common.h>
   9 #include <dm.h>
  10 #include <errno.h>
  11 #include <asm/gpio.h>
  12 #include <asm/io.h>
  13
  14 struct bcm2835_gpios {
  15         struct bcm2835_gpio_regs *reg;
  16 };
  17
  18 static int bcm2835_gpio_direction_input(struct udevice *dev, unsigned gpio)
  19 {
  20         struct bcm2835_gpios *gpios = dev_get_priv(dev);
  21         unsigned val;
  22
  23         val = readl(&gpios->reg->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]);
  24         val &= ~(BCM2835_GPIO_FSEL_MASK << BCM2835_GPIO_FSEL_SHIFT(gpio));
  25         val |= (BCM2835_GPIO_INPUT << BCM2835_GPIO_FSEL_SHIFT(gpio));
  26         writel(val, &gpios->reg->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]);
  27
  28         return 0;
  29 }
  30
  31 static int bcm2835_gpio_direction_output(struct udevice *dev, unsigned gpio,
  32                                          int value)
  33 {
  34         struct bcm2835_gpios *gpios = dev_get_priv(dev);
  35         unsigned val;
  36
  37         gpio_set_value(gpio, value);
  38
  39         val = readl(&gpios->reg->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]);
  40         val &= ~(BCM2835_GPIO_FSEL_MASK << BCM2835_GPIO_FSEL_SHIFT(gpio));
  41         val |= (BCM2835_GPIO_OUTPUT << BCM2835_GPIO_FSEL_SHIFT(gpio));
  42         writel(val, &gpios->reg->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]);
  43
  44         return 0;
  45 }
  46
  47 static bool bcm2835_gpio_is_output(const struct bcm2835_gpios *gpios, int gpio)
  48 {
  49         u32 val;
  50
  51         val = readl(&gpios->reg->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]);
  52         val &= BCM2835_GPIO_FSEL_MASK << BCM2835_GPIO_FSEL_SHIFT(gpio);
  53         return val ? true : false;
  54 }
  55
  56 static int bcm2835_get_value(const struct bcm2835_gpios *gpios, unsigned gpio)
  57 {
  58         unsigned val;
  59
  60         val = readl(&gpios->reg->gplev[BCM2835_GPIO_COMMON_BANK(gpio)]);
  61
  62         return (val >> BCM2835_GPIO_COMMON_SHIFT(gpio)) & 0x1;
  63 }
  64
  65 static int bcm2835_gpio_get_value(struct udevice *dev, unsigned gpio)
  66 {
  67         const struct bcm2835_gpios *gpios = dev_get_priv(dev);
  68
  69         return bcm2835_get_value(gpios, gpio);
  70 }
  71
  72 static int bcm2835_gpio_set_value(struct udevice *dev, unsigned gpio,
  73                                   int value)
  74 {
  75         struct bcm2835_gpios *gpios = dev_get_priv(dev);
  76         u32 *output_reg = value ? gpios->reg->gpset : gpios->reg->gpclr;
  77
  78         writel(1 << BCM2835_GPIO_COMMON_SHIFT(gpio),
  79                                 &output_reg[BCM2835_GPIO_COMMON_BANK(gpio)]);
  80
  81         return 0;
  82 }
  83
  84 static int bcm2835_gpio_get_function(struct udevice *dev, unsigned offset)
  85 {
  86         struct bcm2835_gpios *gpios = dev_get_priv(dev);
  87
  88         /* GPIOF_FUNC is not implemented yet */
  89         if (bcm2835_gpio_is_output(gpios, offset))
  90                 return GPIOF_OUTPUT;
  91         else
  92                 return GPIOF_INPUT;
  93 }
  94
  95
  96 static const struct dm_gpio_ops gpio_bcm2835_ops = {
  97         .direction_input        = bcm2835_gpio_direction_input,
  98         .direction_output       = bcm2835_gpio_direction_output,
  99         .get_value              = bcm2835_gpio_get_value,
 100         .set_value              = bcm2835_gpio_set_value,
 101         .get_function           = bcm2835_gpio_get_function,
 102 };
 103
 104 static int bcm2835_gpio_probe(struct udevice *dev)
 105 {
 106         struct bcm2835_gpios *gpios = dev_get_priv(dev);
 107         struct bcm2835_gpio_platdata *plat = dev_get_platdata(dev);
 108         struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
 109
 110         uc_priv->bank_name = "GPIO";
 111         uc_priv->gpio_count = BCM2835_GPIO_COUNT;
 112         gpios->reg = (struct bcm2835_gpio_regs *)plat->base;
 113
 114         return 0;
 115 }
 116
 117 U_BOOT_DRIVER(gpio_bcm2835) = {
 118         .name   = "gpio_bcm2835",
 119         .id     = UCLASS_GPIO,
 120         .ops    = &gpio_bcm2835_ops,
 121         .probe  = bcm2835_gpio_probe,
 122         .priv_auto_alloc_size = sizeof(struct bcm2835_gpios),
 123 };