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/module.h>
  21 #include <linux/err.h>
  22 #include <linux/errno.h>
  23 #include <linux/ioport.h>
  24 #include <linux/of_device.h>
  25 #include <linux/gpio/driver.h>
  26 #include <linux/platform_device.h>
  27 #include <linux/spinlock.h>
  28 #include <linux/slab.h>
  29
  30 /*
  31  * Only first 8bits of a register correspond to each pin,
  32  * so there are 4 registers for 32 pins.
  33  */
  34 #define PDR(x)  (0x0 + x / 8 * 4)
  35 #define DDR(x)  (0x10 + x / 8 * 4)
  36 #define PFR(x)  (0x20 + x / 8 * 4)
  37
  38 #define OFFSET(x)       BIT((x) % 8)
  39
  40 struct mb86s70_gpio_chip {
  41         struct gpio_chip gc;
  42         void __iomem *base;
  43         struct clk *clk;
  44         spinlock_t lock;
  45 };
  46
  47 static int mb86s70_gpio_request(struct gpio_chip *gc, unsigned gpio)
  48 {
  49         struct mb86s70_gpio_chip *gchip = gpiochip_get_data(gc);
  50         unsigned long flags;
  51         u32 val;
  52
  53         spin_lock_irqsave(&gchip->lock, flags);
  54
  55         val = readl(gchip->base + PFR(gpio));
  56         if (!(val & OFFSET(gpio))) {
  57                 spin_unlock_irqrestore(&gchip->lock, flags);
  58                 return -EINVAL;
  59         }
  60
  61         val &= ~OFFSET(gpio);
  62         writel(val, gchip->base + PFR(gpio));
  63
  64         spin_unlock_irqrestore(&gchip->lock, flags);
  65
  66         return 0;
  67 }
  68
  69 static void mb86s70_gpio_free(struct gpio_chip *gc, unsigned gpio)
  70 {
  71         struct mb86s70_gpio_chip *gchip = gpiochip_get_data(gc);
  72         unsigned long flags;
  73         u32 val;
  74
  75         spin_lock_irqsave(&gchip->lock, flags);
  76
  77         val = readl(gchip->base + PFR(gpio));
  78         val |= OFFSET(gpio);
  79         writel(val, gchip->base + PFR(gpio));
  80
  81         spin_unlock_irqrestore(&gchip->lock, flags);
  82 }
  83
  84 static int mb86s70_gpio_direction_input(struct gpio_chip *gc, unsigned gpio)
  85 {
  86         struct mb86s70_gpio_chip *gchip = gpiochip_get_data(gc);
  87         unsigned long flags;
  88         unsigned char val;
  89
  90         spin_lock_irqsave(&gchip->lock, flags);
  91
  92         val = readl(gchip->base + DDR(gpio));
  93         val &= ~OFFSET(gpio);
  94         writel(val, gchip->base + DDR(gpio));
  95
  96         spin_unlock_irqrestore(&gchip->lock, flags);
  97
  98         return 0;
  99 }
 100
 101 static int mb86s70_gpio_direction_output(struct gpio_chip *gc,
 102                                          unsigned gpio, int value)
 103 {
 104         struct mb86s70_gpio_chip *gchip = gpiochip_get_data(gc);
 105         unsigned long flags;
 106         unsigned char val;
 107
 108         spin_lock_irqsave(&gchip->lock, flags);
 109
 110         val = readl(gchip->base + PDR(gpio));
 111         if (value)
 112                 val |= OFFSET(gpio);
 113         else
 114                 val &= ~OFFSET(gpio);
 115         writel(val, gchip->base + PDR(gpio));
 116
 117         val = readl(gchip->base + DDR(gpio));
 118         val |= OFFSET(gpio);
 119         writel(val, gchip->base + DDR(gpio));
 120
 121         spin_unlock_irqrestore(&gchip->lock, flags);
 122
 123         return 0;
 124 }
 125
 126 static int mb86s70_gpio_get(struct gpio_chip *gc, unsigned gpio)
 127 {
 128         struct mb86s70_gpio_chip *gchip = gpiochip_get_data(gc);
 129
 130         return !!(readl(gchip->base + PDR(gpio)) & OFFSET(gpio));
 131 }
 132
 133 static void mb86s70_gpio_set(struct gpio_chip *gc, unsigned gpio, int value)
 134 {
 135         struct mb86s70_gpio_chip *gchip = gpiochip_get_data(gc);
 136         unsigned long flags;
 137         unsigned char val;
 138
 139         spin_lock_irqsave(&gchip->lock, flags);
 140
 141         val = readl(gchip->base + PDR(gpio));
 142         if (value)
 143                 val |= OFFSET(gpio);
 144         else
 145                 val &= ~OFFSET(gpio);
 146         writel(val, gchip->base + PDR(gpio));
 147
 148         spin_unlock_irqrestore(&gchip->lock, flags);
 149 }
 150
 151 static int mb86s70_gpio_probe(struct platform_device *pdev)
 152 {
 153         struct mb86s70_gpio_chip *gchip;
 154         struct resource *res;
 155         int ret;
 156
 157         gchip = devm_kzalloc(&pdev->dev, sizeof(*gchip), GFP_KERNEL);
 158         if (gchip == NULL)
 159                 return -ENOMEM;
 160
 161         platform_set_drvdata(pdev, gchip);
 162
 163         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 164         gchip->base = devm_ioremap_resource(&pdev->dev, res);
 165         if (IS_ERR(gchip->base))
 166                 return PTR_ERR(gchip->base);
 167
 168         gchip->clk = devm_clk_get(&pdev->dev, NULL);
 169         if (IS_ERR(gchip->clk))
 170                 return PTR_ERR(gchip->clk);
 171
 172         clk_prepare_enable(gchip->clk);
 173
 174         spin_lock_init(&gchip->lock);
 175
 176         gchip->gc.direction_output = mb86s70_gpio_direction_output;
 177         gchip->gc.direction_input = mb86s70_gpio_direction_input;
 178         gchip->gc.request = mb86s70_gpio_request;
 179         gchip->gc.free = mb86s70_gpio_free;
 180         gchip->gc.get = mb86s70_gpio_get;
 181         gchip->gc.set = mb86s70_gpio_set;
 182         gchip->gc.label = dev_name(&pdev->dev);
 183         gchip->gc.ngpio = 32;
 184         gchip->gc.owner = THIS_MODULE;
 185         gchip->gc.parent = &pdev->dev;
 186         gchip->gc.base = -1;
 187
 188         platform_set_drvdata(pdev, gchip);
 189
 190         ret = gpiochip_add_data(&gchip->gc, gchip);
 191         if (ret) {
 192                 dev_err(&pdev->dev, "couldn't register gpio driver\n");
 193                 clk_disable_unprepare(gchip->clk);
 194         }
 195
 196         return ret;
 197 }
 198
 199 static int mb86s70_gpio_remove(struct platform_device *pdev)
 200 {
 201         struct mb86s70_gpio_chip *gchip = platform_get_drvdata(pdev);
 202
 203         gpiochip_remove(&gchip->gc);
 204         clk_disable_unprepare(gchip->clk);
 205
 206         return 0;
 207 }
 208
 209 static const struct of_device_id mb86s70_gpio_dt_ids[] = {
 210         { .compatible = "fujitsu,mb86s70-gpio" },
 211         { /* sentinel */ }
 212 };
 213 MODULE_DEVICE_TABLE(of, mb86s70_gpio_dt_ids);
 214
 215 static struct platform_driver mb86s70_gpio_driver = {
 216         .driver = {
 217                 .name = "mb86s70-gpio",
 218                 .of_match_table = mb86s70_gpio_dt_ids,
 219         },
 220         .probe = mb86s70_gpio_probe,
 221         .remove = mb86s70_gpio_remove,
 222 };
 223
 224 static int __init mb86s70_gpio_init(void)
 225 {
 226         return platform_driver_register(&mb86s70_gpio_driver);
 227 }
 228 module_init(mb86s70_gpio_init);
 229
 230 MODULE_DESCRIPTION("MB86S7x GPIO Driver");
 231 MODULE_ALIAS("platform:mb86s70-gpio");
 232 MODULE_LICENSE("GPL");