drivers/gpio/gpio-mb86s7x.c

   1 /*
   2  *  linux/drivers/gpio/gpio-mb86s7x.c
   3  *
   4  *  Copyright (C) 2015 Fujitsu Semiconductor Limited
   5  *  Copyright (C) 2015 Linaro Ltd.
   6  *
   7  *  This program is free software: you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License as published by
   9  *  the Free Software Foundation, version 2 of the License.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  */
  16
  17 #include <linux/io.h>
  18 #include <linux/init.h>
  19 #include <linux/clk.h>
  20 #include <linux/err.h>
  21 #include <linux/errno.h>
  22 #include <linux/ioport.h>
  23 #include <linux/of_device.h>
  24 #include <linux/gpio/driver.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/spinlock.h>
  27 #include <linux/slab.h>
  28
  29 /*
  30  * Only first 8bits of a register correspond to each pin,
  31  * so there are 4 registers for 32 pins.
  32  */
  33 #define PDR(x)  (0x0 + x / 8 * 4)
  34 #define DDR(x)  (0x10 + x / 8 * 4)
  35 #define PFR(x)  (0x20 + x / 8 * 4)
  36
  37 #define OFFSET(x)       BIT((x) % 8)
  38
  39 struct mb86s70_gpio_chip {
  40         struct gpio_chip gc;
  41         void __iomem *base;
  42         struct clk *clk;
  43         spinlock_t lock;
  44 };
  45
  46 static int mb86s70_gpio_request(struct gpio_chip *gc, unsigned gpio)
  47 {
  48         struct mb86s70_gpio_chip *gchip = gpiochip_get_data(gc);
  49         unsigned long flags;
  50         u32 val;
  51
  52         spin_lock_irqsave(&gchip->lock, flags);
  53
  54         val = readl(gchip->base + PFR(gpio));
  55         if (!(val & OFFSET(gpio))) {
  56                 spin_unlock_irqrestore(&gchip->lock, flags);
  57                 return -EINVAL;
  58         }
  59
  60         val &= ~OFFSET(gpio);
  61         writel(val, gchip->base + PFR(gpio));
  62
  63         spin_unlock_irqrestore(&gchip->lock, flags);
  64
  65         return 0;
  66 }
  67
  68 static void mb86s70_gpio_free(struct gpio_chip *gc, unsigned gpio)
  69 {
  70         struct mb86s70_gpio_chip *gchip = gpiochip_get_data(gc);
  71         unsigned long flags;
  72         u32 val;
  73
  74         spin_lock_irqsave(&gchip->lock, flags);
  75
  76         val = readl(gchip->base + PFR(gpio));
  77         val |= OFFSET(gpio);
  78         writel(val, gchip->base + PFR(gpio));
  79
  80         spin_unlock_irqrestore(&gchip->lock, flags);
  81 }
  82
  83 static int mb86s70_gpio_direction_input(struct gpio_chip *gc, unsigned gpio)
  84 {
  85         struct mb86s70_gpio_chip *gchip = gpiochip_get_data(gc);
  86         unsigned long flags;
  87         unsigned char val;
  88
  89         spin_lock_irqsave(&gchip->lock, flags);
  90
  91         val = readl(gchip->base + DDR(gpio));
  92         val &= ~OFFSET(gpio);
  93         writel(val, gchip->base + DDR(gpio));
  94
  95         spin_unlock_irqrestore(&gchip->lock, flags);
  96
  97         return 0;
  98 }
  99
 100 static int mb86s70_gpio_direction_output(struct gpio_chip *gc,
 101                                          unsigned gpio, int value)
 102 {
 103         struct mb86s70_gpio_chip *gchip = gpiochip_get_data(gc);
 104         unsigned long flags;
 105         unsigned char val;
 106
 107         spin_lock_irqsave(&gchip->lock, flags);
 108
 109         val = readl(gchip->base + PDR(gpio));
 110         if (value)
 111                 val |= OFFSET(gpio);
 112         else
 113                 val &= ~OFFSET(gpio);
 114         writel(val, gchip->base + PDR(gpio));
 115
 116         val = readl(gchip->base + DDR(gpio));
 117         val |= OFFSET(gpio);
 118         writel(val, gchip->base + DDR(gpio));
 119
 120         spin_unlock_irqrestore(&gchip->lock, flags);
 121
 122         return 0;
 123 }
 124
 125 static int mb86s70_gpio_get(struct gpio_chip *gc, unsigned gpio)
 126 {
 127         struct mb86s70_gpio_chip *gchip = gpiochip_get_data(gc);
 128
 129         return !!(readl(gchip->base + PDR(gpio)) & OFFSET(gpio));
 130 }
 131
 132 static void mb86s70_gpio_set(struct gpio_chip *gc, unsigned gpio, int value)
 133 {
 134         struct mb86s70_gpio_chip *gchip = gpiochip_get_data(gc);
 135         unsigned long flags;
 136         unsigned char val;
 137
 138         spin_lock_irqsave(&gchip->lock, flags);
 139
 140         val = readl(gchip->base + PDR(gpio));
 141         if (value)
 142                 val |= OFFSET(gpio);
 143         else
 144                 val &= ~OFFSET(gpio);
 145         writel(val, gchip->base + PDR(gpio));
 146
 147         spin_unlock_irqrestore(&gchip->lock, flags);
 148 }
 149
 150 static int mb86s70_gpio_probe(struct platform_device *pdev)
 151 {
 152         struct mb86s70_gpio_chip *gchip;
 153         struct resource *res;
 154         int ret;
 155
 156         gchip = devm_kzalloc(&pdev->dev, sizeof(*gchip), GFP_KERNEL);
 157         if (gchip == NULL)
 158                 return -ENOMEM;
 159
 160         platform_set_drvdata(pdev, gchip);
 161
 162         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 163         gchip->base = devm_ioremap_resource(&pdev->dev, res);
 164         if (IS_ERR(gchip->base))
 165                 return PTR_ERR(gchip->base);
 166
 167         gchip->clk = devm_clk_get(&pdev->dev, NULL);
 168         if (IS_ERR(gchip->clk))
 169                 return PTR_ERR(gchip->clk);
 170
 171         clk_prepare_enable(gchip->clk);
 172
 173         spin_lock_init(&gchip->lock);
 174
 175         gchip->gc.direction_output = mb86s70_gpio_direction_output;
 176         gchip->gc.direction_input = mb86s70_gpio_direction_input;
 177         gchip->gc.request = mb86s70_gpio_request;
 178         gchip->gc.free = mb86s70_gpio_free;
 179         gchip->gc.get = mb86s70_gpio_get;
 180         gchip->gc.set = mb86s70_gpio_set;
 181         gchip->gc.label = dev_name(&pdev->dev);
 182         gchip->gc.ngpio = 32;
 183         gchip->gc.owner = THIS_MODULE;
 184         gchip->gc.parent = &pdev->dev;
 185         gchip->gc.base = -1;
 186
 187         ret = gpiochip_add_data(&gchip->gc, gchip);
 188         if (ret) {
 189                 dev_err(&pdev->dev, "couldn't register gpio driver\n");
 190                 clk_disable_unprepare(gchip->clk);
 191         }
 192
 193         return ret;
 194 }
 195
 196 static int mb86s70_gpio_remove(struct platform_device *pdev)
 197 {
 198         struct mb86s70_gpio_chip *gchip = platform_get_drvdata(pdev);
 199
 200         gpiochip_remove(&gchip->gc);
 201         clk_disable_unprepare(gchip->clk);
 202
 203         return 0;
 204 }
 205
 206 static const struct of_device_id mb86s70_gpio_dt_ids[] = {
 207         { .compatible = "fujitsu,mb86s70-gpio" },
 208         { /* sentinel */ }
 209 };
 210
 211 static struct platform_driver mb86s70_gpio_driver = {
 212         .driver = {
 213                 .name = "mb86s70-gpio",
 214                 .of_match_table = mb86s70_gpio_dt_ids,
 215         },
 216         .probe = mb86s70_gpio_probe,
 217         .remove = mb86s70_gpio_remove,
 218 };
 219
 220 static int __init mb86s70_gpio_init(void)
 221 {
 222         return platform_driver_register(&mb86s70_gpio_driver);
 223 }
 224 device_initcall(mb86s70_gpio_init);