arch/mips/kernel/gpio_txx9.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * A gpio chip driver for TXx9 SoCs
   4  *
   5  * Copyright (C) 2008 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
   6  */
   7
   8 #include <linux/init.h>
   9 #include <linux/spinlock.h>
  10 #include <linux/gpio/driver.h>
  11 #include <linux/errno.h>
  12 #include <linux/io.h>
  13 #include <asm/txx9pio.h>
  14
  15 static DEFINE_SPINLOCK(txx9_gpio_lock);
  16
  17 static struct txx9_pio_reg __iomem *txx9_pioptr;
  18
  19 static int txx9_gpio_get(struct gpio_chip *chip, unsigned int offset)
  20 {
  21         return !!(__raw_readl(&txx9_pioptr->din) & (1 << offset));
  22 }
  23
  24 static void txx9_gpio_set_raw(unsigned int offset, int value)
  25 {
  26         u32 val;
  27         val = __raw_readl(&txx9_pioptr->dout);
  28         if (value)
  29                 val |= 1 << offset;
  30         else
  31                 val &= ~(1 << offset);
  32         __raw_writel(val, &txx9_pioptr->dout);
  33 }
  34
  35 static void txx9_gpio_set(struct gpio_chip *chip, unsigned int offset,
  36                           int value)
  37 {
  38         unsigned long flags;
  39         spin_lock_irqsave(&txx9_gpio_lock, flags);
  40         txx9_gpio_set_raw(offset, value);
  41         mmiowb();
  42         spin_unlock_irqrestore(&txx9_gpio_lock, flags);
  43 }
  44
  45 static int txx9_gpio_dir_in(struct gpio_chip *chip, unsigned int offset)
  46 {
  47         unsigned long flags;
  48         spin_lock_irqsave(&txx9_gpio_lock, flags);
  49         __raw_writel(__raw_readl(&txx9_pioptr->dir) & ~(1 << offset),
  50                      &txx9_pioptr->dir);
  51         mmiowb();
  52         spin_unlock_irqrestore(&txx9_gpio_lock, flags);
  53         return 0;
  54 }
  55
  56 static int txx9_gpio_dir_out(struct gpio_chip *chip, unsigned int offset,
  57                              int value)
  58 {
  59         unsigned long flags;
  60         spin_lock_irqsave(&txx9_gpio_lock, flags);
  61         txx9_gpio_set_raw(offset, value);
  62         __raw_writel(__raw_readl(&txx9_pioptr->dir) | (1 << offset),
  63                      &txx9_pioptr->dir);
  64         mmiowb();
  65         spin_unlock_irqrestore(&txx9_gpio_lock, flags);
  66         return 0;
  67 }
  68
  69 static struct gpio_chip txx9_gpio_chip = {
  70         .get = txx9_gpio_get,
  71         .set = txx9_gpio_set,
  72         .direction_input = txx9_gpio_dir_in,
  73         .direction_output = txx9_gpio_dir_out,
  74         .label = "TXx9",
  75 };
  76
  77 int __init txx9_gpio_init(unsigned long baseaddr,
  78                           unsigned int base, unsigned int num)
  79 {
  80         txx9_pioptr = ioremap(baseaddr, sizeof(struct txx9_pio_reg));
  81         if (!txx9_pioptr)
  82                 return -ENODEV;
  83         txx9_gpio_chip.base = base;
  84         txx9_gpio_chip.ngpio = num;
  85         return gpiochip_add_data(&txx9_gpio_chip, NULL);
  86 }