LXR linux/drivers/platform/x86/intel_mid

   1/*
   2 * Power button driver for Medfield.
   3 *
   4 * Copyright (C) 2010 Intel Corp
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; version 2 of the License.
   9 *
  10 * This program is distributed in the hope that it will be useful, but
  11 * WITHOUT ANY WARRANTY; without even the implied warranty of
  12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  13 * General Public License for more details.
  14 *
  15 * You should have received a copy of the GNU General Public License along
  16 * with this program; if not, write to the Free Software Foundation, Inc.,
  17 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  18 */
  19
  20#include <linux/module.h>
  21#include <linux/init.h>
  22#include <linux/interrupt.h>
  23#include <linux/slab.h>
  24#include <linux/platform_device.h>
  25#include <linux/input.h>
  26#include <linux/mfd/intel_msic.h>
  27#include <linux/pm_wakeirq.h>
  28
  29#define DRIVER_NAME "msic_power_btn"
  30
  31#define MSIC_PB_LEVEL   (1 << 3) /* 1 - release, 0 - press */
  32
  33/*
  34 * MSIC document ti_datasheet defines the 1st bit reg 0x21 is used to mask
  35 * power button interrupt
  36 */
  37#define MSIC_PWRBTNM    (1 << 0)
  38
  39static irqreturn_t mfld_pb_isr(int irq, void *dev_id)
  40{
  41        struct input_dev *input = dev_id;
  42        int ret;
  43        u8 pbstat;
  44
  45        ret = intel_msic_reg_read(INTEL_MSIC_PBSTATUS, &pbstat);
  46        dev_dbg(input->dev.parent, "PB_INT status= %d\n", pbstat);
  47
  48        if (ret < 0) {
  49                dev_err(input->dev.parent, "Read error %d while reading"
  50                               " MSIC_PB_STATUS\n", ret);
  51        } else {
  52                input_event(input, EV_KEY, KEY_POWER,
  53                               !(pbstat & MSIC_PB_LEVEL));
  54                input_sync(input);
  55        }
  56
  57        return IRQ_HANDLED;
  58}
  59
  60static int mfld_pb_probe(struct platform_device *pdev)
  61{
  62        struct input_dev *input;
  63        int irq = platform_get_irq(pdev, 0);
  64        int error;
  65
  66        if (irq < 0)
  67                return -EINVAL;
  68
  69        input = input_allocate_device();
  70        if (!input)
  71                return -ENOMEM;
  72
  73        input->name = pdev->name;
  74        input->phys = "power-button/input0";
  75        input->id.bustype = BUS_HOST;
  76        input->dev.parent = &pdev->dev;
  77
  78        input_set_capability(input, EV_KEY, KEY_POWER);
  79
  80        error = request_threaded_irq(irq, NULL, mfld_pb_isr, 0,
  81                                     DRIVER_NAME, input);
  82        if (error) {
  83                dev_err(&pdev->dev, "Unable to request irq %d for mfld power"
  84                                "button\n", irq);
  85                goto err_free_input;
  86        }
  87
  88        device_init_wakeup(&pdev->dev, true);
  89        dev_pm_set_wake_irq(&pdev->dev, irq);
  90
  91        error = input_register_device(input);
  92        if (error) {
  93                dev_err(&pdev->dev, "Unable to register input dev, error "
  94                                "%d\n", error);
  95                goto err_free_irq;
  96        }
  97
  98        platform_set_drvdata(pdev, input);
  99
 100        /*
 101         * SCU firmware might send power button interrupts to IA core before
 102         * kernel boots and doesn't get EOI from IA core. The first bit of
 103         * MSIC reg 0x21 is kept masked, and SCU firmware doesn't send new
 104         * power interrupt to Android kernel. Unmask the bit when probing
 105         * power button in kernel.
 106         * There is a very narrow race between irq handler and power button
 107         * initialization. The race happens rarely. So we needn't worry
 108         * about it.
 109         */
 110        error = intel_msic_reg_update(INTEL_MSIC_IRQLVL1MSK, 0, MSIC_PWRBTNM);
 111        if (error) {
 112                dev_err(&pdev->dev, "Unable to clear power button interrupt, "
 113                                "error: %d\n", error);
 114                goto err_free_irq;
 115        }
 116
 117        return 0;
 118
 119err_free_irq:
 120        free_irq(irq, input);
 121err_free_input:
 122        input_free_device(input);
 123        return error;
 124}
 125
 126static int mfld_pb_remove(struct platform_device *pdev)
 127{
 128        struct input_dev *input = platform_get_drvdata(pdev);
 129        int irq = platform_get_irq(pdev, 0);
 130
 131        dev_pm_clear_wake_irq(&pdev->dev);
 132        device_init_wakeup(&pdev->dev, false);
 133        free_irq(irq, input);
 134        input_unregister_device(input);
 135
 136        return 0;
 137}
 138
 139static struct platform_driver mfld_pb_driver = {
 140        .driver = {
 141                .name = DRIVER_NAME,
 142        },
 143        .probe  = mfld_pb_probe,
 144        .remove = mfld_pb_remove,
 145};
 146
 147module_platform_driver(mfld_pb_driver);
 148
 149MODULE_AUTHOR("Hong Liu <hong.liu@intel.com>");
 150MODULE_DESCRIPTION("Intel Medfield Power Button Driver");
 151MODULE_LICENSE("GPL v2");
 152MODULE_ALIAS("platform:" DRIVER_NAME);
 153