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);