LXR linux/drivers/gpio/gpio-sch.c

   1/*
   2 * GPIO interface for Intel Poulsbo SCH
   3 *
   4 *  Copyright (c) 2010 CompuLab Ltd
   5 *  Author: Denis Turischev <denis@compulab.co.il>
   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 2 as published
   9 *  by the Free Software Foundation.
  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 *  You should have received a copy of the GNU General Public License
  17 *  along with this program; see the file COPYING.  If not, write to
  18 *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  19 */
  20
  21#include <linux/init.h>
  22#include <linux/kernel.h>
  23#include <linux/module.h>
  24#include <linux/io.h>
  25#include <linux/errno.h>
  26#include <linux/acpi.h>
  27#include <linux/platform_device.h>
  28#include <linux/pci_ids.h>
  29
  30#include <linux/gpio.h>
  31
  32#define GEN     0x00
  33#define GIO     0x04
  34#define GLV     0x08
  35
  36struct sch_gpio {
  37        struct gpio_chip chip;
  38        spinlock_t lock;
  39        unsigned short iobase;
  40        unsigned short core_base;
  41        unsigned short resume_base;
  42};
  43
  44static unsigned sch_gpio_offset(struct sch_gpio *sch, unsigned gpio,
  45                                unsigned reg)
  46{
  47        unsigned base = 0;
  48
  49        if (gpio >= sch->resume_base) {
  50                gpio -= sch->resume_base;
  51                base += 0x20;
  52        }
  53
  54        return base + reg + gpio / 8;
  55}
  56
  57static unsigned sch_gpio_bit(struct sch_gpio *sch, unsigned gpio)
  58{
  59        if (gpio >= sch->resume_base)
  60                gpio -= sch->resume_base;
  61        return gpio % 8;
  62}
  63
  64static int sch_gpio_reg_get(struct sch_gpio *sch, unsigned gpio, unsigned reg)
  65{
  66        unsigned short offset, bit;
  67        u8 reg_val;
  68
  69        offset = sch_gpio_offset(sch, gpio, reg);
  70        bit = sch_gpio_bit(sch, gpio);
  71
  72        reg_val = !!(inb(sch->iobase + offset) & BIT(bit));
  73
  74        return reg_val;
  75}
  76
  77static void sch_gpio_reg_set(struct sch_gpio *sch, unsigned gpio, unsigned reg,
  78                             int val)
  79{
  80        unsigned short offset, bit;
  81        u8 reg_val;
  82
  83        offset = sch_gpio_offset(sch, gpio, reg);
  84        bit = sch_gpio_bit(sch, gpio);
  85
  86        reg_val = inb(sch->iobase + offset);
  87
  88        if (val)
  89                outb(reg_val | BIT(bit), sch->iobase + offset);
  90        else
  91                outb((reg_val & ~BIT(bit)), sch->iobase + offset);
  92}
  93
  94static int sch_gpio_direction_in(struct gpio_chip *gc, unsigned gpio_num)
  95{
  96        struct sch_gpio *sch = gpiochip_get_data(gc);
  97
  98        spin_lock(&sch->lock);
  99        sch_gpio_reg_set(sch, gpio_num, GIO, 1);
 100        spin_unlock(&sch->lock);
 101        return 0;
 102}
 103
 104static int sch_gpio_get(struct gpio_chip *gc, unsigned gpio_num)
 105{
 106        struct sch_gpio *sch = gpiochip_get_data(gc);
 107        return sch_gpio_reg_get(sch, gpio_num, GLV);
 108}
 109
 110static void sch_gpio_set(struct gpio_chip *gc, unsigned gpio_num, int val)
 111{
 112        struct sch_gpio *sch = gpiochip_get_data(gc);
 113
 114        spin_lock(&sch->lock);
 115        sch_gpio_reg_set(sch, gpio_num, GLV, val);
 116        spin_unlock(&sch->lock);
 117}
 118
 119static int sch_gpio_direction_out(struct gpio_chip *gc, unsigned gpio_num,
 120                                  int val)
 121{
 122        struct sch_gpio *sch = gpiochip_get_data(gc);
 123
 124        spin_lock(&sch->lock);
 125        sch_gpio_reg_set(sch, gpio_num, GIO, 0);
 126        spin_unlock(&sch->lock);
 127
 128        /*
 129         * according to the datasheet, writing to the level register has no
 130         * effect when GPIO is programmed as input.
 131         * Actually the the level register is read-only when configured as input.
 132         * Thus presetting the output level before switching to output is _NOT_ possible.
 133         * Hence we set the level after configuring the GPIO as output.
 134         * But we cannot prevent a short low pulse if direction is set to high
 135         * and an external pull-up is connected.
 136         */
 137        sch_gpio_set(gc, gpio_num, val);
 138        return 0;
 139}
 140
 141static const struct gpio_chip sch_gpio_chip = {
 142        .label                  = "sch_gpio",
 143        .owner                  = THIS_MODULE,
 144        .direction_input        = sch_gpio_direction_in,
 145        .get                    = sch_gpio_get,
 146        .direction_output       = sch_gpio_direction_out,
 147        .set                    = sch_gpio_set,
 148};
 149
 150static int sch_gpio_probe(struct platform_device *pdev)
 151{
 152        struct sch_gpio *sch;
 153        struct resource *res;
 154
 155        sch = devm_kzalloc(&pdev->dev, sizeof(*sch), GFP_KERNEL);
 156        if (!sch)
 157                return -ENOMEM;
 158
 159        res = platform_get_resource(pdev, IORESOURCE_IO, 0);
 160        if (!res)
 161                return -EBUSY;
 162
 163        if (!devm_request_region(&pdev->dev, res->start, resource_size(res),
 164                                 pdev->name))
 165                return -EBUSY;
 166
 167        spin_lock_init(&sch->lock);
 168        sch->iobase = res->start;
 169        sch->chip = sch_gpio_chip;
 170        sch->chip.label = dev_name(&pdev->dev);
 171        sch->chip.parent = &pdev->dev;
 172
 173        switch (pdev->id) {
 174        case PCI_DEVICE_ID_INTEL_SCH_LPC:
 175                sch->core_base = 0;
 176                sch->resume_base = 10;
 177                sch->chip.ngpio = 14;
 178
 179                /*
 180                 * GPIO[6:0] enabled by default
 181                 * GPIO7 is configured by the CMC as SLPIOVR
 182                 * Enable GPIO[9:8] core powered gpios explicitly
 183                 */
 184                sch_gpio_reg_set(sch, 8, GEN, 1);
 185                sch_gpio_reg_set(sch, 9, GEN, 1);
 186                /*
 187                 * SUS_GPIO[2:0] enabled by default
 188                 * Enable SUS_GPIO3 resume powered gpio explicitly
 189                 */
 190                sch_gpio_reg_set(sch, 13, GEN, 1);
 191                break;
 192
 193        case PCI_DEVICE_ID_INTEL_ITC_LPC:
 194                sch->core_base = 0;
 195                sch->resume_base = 5;
 196                sch->chip.ngpio = 14;
 197                break;
 198
 199        case PCI_DEVICE_ID_INTEL_CENTERTON_ILB:
 200                sch->core_base = 0;
 201                sch->resume_base = 21;
 202                sch->chip.ngpio = 30;
 203                break;
 204
 205        case PCI_DEVICE_ID_INTEL_QUARK_X1000_ILB:
 206                sch->core_base = 0;
 207                sch->resume_base = 2;
 208                sch->chip.ngpio = 8;
 209                break;
 210
 211        default:
 212                return -ENODEV;
 213        }
 214
 215        platform_set_drvdata(pdev, sch);
 216
 217        return devm_gpiochip_add_data(&pdev->dev, &sch->chip, sch);
 218}
 219
 220static struct platform_driver sch_gpio_driver = {
 221        .driver = {
 222                .name = "sch_gpio",
 223        },
 224        .probe          = sch_gpio_probe,
 225};
 226
 227module_platform_driver(sch_gpio_driver);
 228
 229MODULE_AUTHOR("Denis Turischev <denis@compulab.co.il>");
 230MODULE_DESCRIPTION("GPIO interface for Intel Poulsbo SCH");
 231MODULE_LICENSE("GPL");
 232MODULE_ALIAS("platform:sch_gpio");
 233