1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Power button driver for Intel MID platforms.
  4 *
  5 * Copyright (C) 2010,2017 Intel Corp
  6 *
  7 * Author: Hong Liu <hong.liu@intel.com>
  8 * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
  9 */
 10
 11#include <linux/input.h>
 12#include <linux/interrupt.h>
 13#include <linux/mfd/intel_msic.h>
 14#include <linux/module.h>
 15#include <linux/platform_device.h>
 16#include <linux/pm_wakeirq.h>
 17#include <linux/slab.h>
 18
 19#include <asm/cpu_device_id.h>
 20#include <asm/intel-family.h>
 21#include <asm/intel_scu_ipc.h>
 22
 23#define DRIVER_NAME "msic_power_btn"
 24
 25#define MSIC_PB_LEVEL	(1 << 3) /* 1 - release, 0 - press */
 26
 27/*
 28 * MSIC document ti_datasheet defines the 1st bit reg 0x21 is used to mask
 29 * power button interrupt
 30 */
 31#define MSIC_PWRBTNM    (1 << 0)
 32
 33/* Intel Tangier */
 34#define BCOVE_PB_LEVEL		(1 << 4)	/* 1 - release, 0 - press */
 35
 36/* Basin Cove PMIC */
 37#define BCOVE_PBIRQ		0x02
 38#define BCOVE_IRQLVL1MSK	0x0c
 39#define BCOVE_PBIRQMASK		0x0d
 40#define BCOVE_PBSTATUS		0x27
 41
 42struct mid_pb_ddata {
 43	struct device *dev;
 44	int irq;
 45	struct input_dev *input;
 46	unsigned short mirqlvl1_addr;
 47	unsigned short pbstat_addr;
 48	u8 pbstat_mask;
 49	int (*setup)(struct mid_pb_ddata *ddata);
 50};
 51
 52static int mid_pbstat(struct mid_pb_ddata *ddata, int *value)
 53{
 54	struct input_dev *input = ddata->input;
 55	int ret;
 56	u8 pbstat;
 57
 58	ret = intel_scu_ipc_ioread8(ddata->pbstat_addr, &pbstat);
 59	if (ret)
 60		return ret;
 61
 62	dev_dbg(input->dev.parent, "PB_INT status= %d\n", pbstat);
 63
 64	*value = !(pbstat & ddata->pbstat_mask);
 65	return 0;
 66}
 67
 68static int mid_irq_ack(struct mid_pb_ddata *ddata)
 69{
 70	return intel_scu_ipc_update_register(ddata->mirqlvl1_addr, 0, MSIC_PWRBTNM);
 71}
 72
 73static int mrfld_setup(struct mid_pb_ddata *ddata)
 74{
 75	/* Unmask the PBIRQ and MPBIRQ on Tangier */
 76	intel_scu_ipc_update_register(BCOVE_PBIRQ, 0, MSIC_PWRBTNM);
 77	intel_scu_ipc_update_register(BCOVE_PBIRQMASK, 0, MSIC_PWRBTNM);
 78
 79	return 0;
 80}
 81
 82static irqreturn_t mid_pb_isr(int irq, void *dev_id)
 83{
 84	struct mid_pb_ddata *ddata = dev_id;
 85	struct input_dev *input = ddata->input;
 86	int value = 0;
 87	int ret;
 88
 89	ret = mid_pbstat(ddata, &value);
 90	if (ret < 0) {
 91		dev_err(input->dev.parent,
 92			"Read error %d while reading MSIC_PB_STATUS\n", ret);
 93	} else {
 94		input_event(input, EV_KEY, KEY_POWER, value);
 95		input_sync(input);
 96	}
 97
 98	mid_irq_ack(ddata);
 99	return IRQ_HANDLED;
100}
101
102static const struct mid_pb_ddata mfld_ddata = {
103	.mirqlvl1_addr	= INTEL_MSIC_IRQLVL1MSK,
104	.pbstat_addr	= INTEL_MSIC_PBSTATUS,
105	.pbstat_mask	= MSIC_PB_LEVEL,
106};
107
108static const struct mid_pb_ddata mrfld_ddata = {
109	.mirqlvl1_addr	= BCOVE_IRQLVL1MSK,
110	.pbstat_addr	= BCOVE_PBSTATUS,
111	.pbstat_mask	= BCOVE_PB_LEVEL,
112	.setup	= mrfld_setup,
113};
114
115static const struct x86_cpu_id mid_pb_cpu_ids[] = {
116	INTEL_CPU_FAM6(ATOM_SALTWELL_MID,	mfld_ddata),
117	INTEL_CPU_FAM6(ATOM_SILVERMONT_MID,	mrfld_ddata),
118	{}
119};
120
121static int mid_pb_probe(struct platform_device *pdev)
122{
123	const struct x86_cpu_id *id;
124	struct mid_pb_ddata *ddata;
125	struct input_dev *input;
126	int irq = platform_get_irq(pdev, 0);
127	int error;
128
129	id = x86_match_cpu(mid_pb_cpu_ids);
130	if (!id)
131		return -ENODEV;
132
133	if (irq < 0) {
134		dev_err(&pdev->dev, "Failed to get IRQ: %d\n", irq);
135		return irq;
136	}
137
138	input = devm_input_allocate_device(&pdev->dev);
139	if (!input)
140		return -ENOMEM;
141
142	input->name = pdev->name;
143	input->phys = "power-button/input0";
144	input->id.bustype = BUS_HOST;
145	input->dev.parent = &pdev->dev;
146
147	input_set_capability(input, EV_KEY, KEY_POWER);
148
149	ddata = (struct mid_pb_ddata *)id->driver_data;
150	if (!ddata)
151		return -ENODATA;
152
153	ddata->dev = &pdev->dev;
154	ddata->irq = irq;
155	ddata->input = input;
156
157	if (ddata->setup) {
158		error = ddata->setup(ddata);
159		if (error)
160			return error;
161	}
162
163	error = devm_request_threaded_irq(&pdev->dev, irq, NULL, mid_pb_isr,
164					  IRQF_ONESHOT, DRIVER_NAME, ddata);
165	if (error) {
166		dev_err(&pdev->dev,
167			"Unable to request irq %d for MID power button\n", irq);
168		return error;
169	}
170
171	error = input_register_device(input);
172	if (error) {
173		dev_err(&pdev->dev,
174			"Unable to register input dev, error %d\n", error);
175		return error;
176	}
177
178	platform_set_drvdata(pdev, ddata);
179
180	/*
181	 * SCU firmware might send power button interrupts to IA core before
182	 * kernel boots and doesn't get EOI from IA core. The first bit of
183	 * MSIC reg 0x21 is kept masked, and SCU firmware doesn't send new
184	 * power interrupt to Android kernel. Unmask the bit when probing
185	 * power button in kernel.
186	 * There is a very narrow race between irq handler and power button
187	 * initialization. The race happens rarely. So we needn't worry
188	 * about it.
189	 */
190	error = mid_irq_ack(ddata);
191	if (error) {
192		dev_err(&pdev->dev,
193			"Unable to clear power button interrupt, error: %d\n",
194			error);
195		return error;
196	}
197
198	device_init_wakeup(&pdev->dev, true);
199	dev_pm_set_wake_irq(&pdev->dev, irq);
200
201	return 0;
202}
203
204static int mid_pb_remove(struct platform_device *pdev)
205{
206	dev_pm_clear_wake_irq(&pdev->dev);
207	device_init_wakeup(&pdev->dev, false);
208
209	return 0;
210}
211
212static struct platform_driver mid_pb_driver = {
213	.driver = {
214		.name = DRIVER_NAME,
215	},
216	.probe	= mid_pb_probe,
217	.remove	= mid_pb_remove,
218};
219
220module_platform_driver(mid_pb_driver);
221
222MODULE_AUTHOR("Hong Liu <hong.liu@intel.com>");
223MODULE_DESCRIPTION("Intel MID Power Button Driver");
224MODULE_LICENSE("GPL v2");
225MODULE_ALIAS("platform:" DRIVER_NAME);