tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
28#define DRIVER_NAME "msic_power_btn"
29
30#define MSIC_PB_LEVEL (1 << 3) /* 1 - release, 0 - press */
31
32/*
33 * MSIC document ti_datasheet defines the 1st bit reg 0x21 is used to mask
34 * power button interrupt
35 */
36#define MSIC_PWRBTNM (1 << 0)
37
38static irqreturn_t mfld_pb_isr(int irq, void *dev_id)
39{
40 struct input_dev *input = dev_id;
41 int ret;
42 u8 pbstat;
43
44 ret = intel_msic_reg_read(INTEL_MSIC_PBSTATUS, &pbstat);
45 dev_dbg(input->dev.parent, "PB_INT status= %d\n", pbstat);
46
47 if (ret < 0) {
48 dev_err(input->dev.parent, "Read error %d while reading"
49 " MSIC_PB_STATUS\n", ret);
50 } else {
51 input_event(input, EV_KEY, KEY_POWER,
52 !(pbstat & MSIC_PB_LEVEL));
53 input_sync(input);
54 }
55
56 return IRQ_HANDLED;
57}
58
59static int mfld_pb_probe(struct platform_device *pdev)
60{
61 struct input_dev *input;
62 int irq = platform_get_irq(pdev, 0);
63 int error;
64
65 if (irq < 0)
66 return -EINVAL;
67
68 input = input_allocate_device();
69 if (!input) {
70 dev_err(&pdev->dev, "Input device allocation error\n");
71 return -ENOMEM;
72 }
73
74 input->name = pdev->name;
75 input->phys = "power-button/input0";
76 input->id.bustype = BUS_HOST;
77 input->dev.parent = &pdev->dev;
78
79 input_set_capability(input, EV_KEY, KEY_POWER);
80
81 error = request_threaded_irq(irq, NULL, mfld_pb_isr, IRQF_NO_SUSPEND,
82 DRIVER_NAME, input);
83 if (error) {
84 dev_err(&pdev->dev, "Unable to request irq %d for mfld power"
85 "button\n", irq);
86 goto err_free_input;
87 }
88
89 error = input_register_device(input);
90 if (error) {
91 dev_err(&pdev->dev, "Unable to register input dev, error "
92 "%d\n", error);
93 goto err_free_irq;
94 }
95
96 platform_set_drvdata(pdev, input);
97
98 /*
99 * SCU firmware might send power button interrupts to IA core before
100 * kernel boots and doesn't get EOI from IA core. The first bit of
101 * MSIC reg 0x21 is kept masked, and SCU firmware doesn't send new
102 * power interrupt to Android kernel. Unmask the bit when probing
103 * power button in kernel.
104 * There is a very narrow race between irq handler and power button
105 * initialization. The race happens rarely. So we needn't worry
106 * about it.
107 */
108 error = intel_msic_reg_update(INTEL_MSIC_IRQLVL1MSK, 0, MSIC_PWRBTNM);
109 if (error) {
110 dev_err(&pdev->dev, "Unable to clear power button interrupt, "
111 "error: %d\n", error);
112 goto err_free_irq;
113 }
114
115 return 0;
116
117err_free_irq:
118 free_irq(irq, input);
119err_free_input:
120 input_free_device(input);
121 return error;
122}
123
124static int mfld_pb_remove(struct platform_device *pdev)
125{
126 struct input_dev *input = platform_get_drvdata(pdev);
127 int irq = platform_get_irq(pdev, 0);
128
129 free_irq(irq, input);
130 input_unregister_device(input);
131 platform_set_drvdata(pdev, NULL);
132
133 return 0;
134}
135
136static struct platform_driver mfld_pb_driver = {
137 .driver = {
138 .name = DRIVER_NAME,
139 .owner = THIS_MODULE,
140 },
141 .probe = mfld_pb_probe,
142 .remove = mfld_pb_remove,
143};
144
145module_platform_driver(mfld_pb_driver);
146
147MODULE_AUTHOR("Hong Liu <hong.liu@intel.com>");
148MODULE_DESCRIPTION("Intel Medfield Power Button Driver");
149MODULE_LICENSE("GPL v2");
150MODULE_ALIAS("platform:" DRIVER_NAME);