drivers/platform/x86/intel_mid_powerbtn.c

   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
  39 static 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
  60 static 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, IRQF_ONESHOT,
  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
 119 err_free_irq:
 120         free_irq(irq, input);
 121 err_free_input:
 122         input_free_device(input);
 123         return error;
 124 }
 125
 126 static 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
 139 static 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
 147 module_platform_driver(mfld_pb_driver);
 148
 149 MODULE_AUTHOR("Hong Liu <hong.liu@intel.com>");
 150 MODULE_DESCRIPTION("Intel Medfield Power Button Driver");
 151 MODULE_LICENSE("GPL v2");
 152 MODULE_ALIAS("platform:" DRIVER_NAME);