1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Power-source driver for Bay Trail Crystal Cove PMIC
  4 *
  5 * Copyright (c) 2023 Hans de Goede <hdegoede@redhat.com>
  6 *
  7 * Based on intel_crystalcove_pwrsrc.c from Android kernel sources, which is:
  8 * Copyright (C) 2013 Intel Corporation
  9 */
 10
 11#include <linux/debugfs.h>
 12#include <linux/mfd/intel_soc_pmic.h>
 13#include <linux/module.h>
 14#include <linux/platform_device.h>
 15#include <linux/regmap.h>
 16
 17#define CRYSTALCOVE_SPWRSRC_REG		0x1E
 18#define CRYSTALCOVE_RESETSRC0_REG	0x20
 19#define CRYSTALCOVE_RESETSRC1_REG	0x21
 20#define CRYSTALCOVE_WAKESRC_REG		0x22
 21
 22struct crc_pwrsrc_data {
 23	struct regmap *regmap;
 24	struct dentry *debug_dentry;
 25	unsigned int resetsrc0;
 26	unsigned int resetsrc1;
 27	unsigned int wakesrc;
 28};
 29
 30static const char * const pwrsrc_pwrsrc_info[] = {
 31	/* bit 0 */ "USB",
 32	/* bit 1 */ "DC in",
 33	/* bit 2 */ "Battery",
 34	NULL,
 35};
 36
 37static const char * const pwrsrc_resetsrc0_info[] = {
 38	/* bit 0 */ "SOC reporting a thermal event",
 39	/* bit 1 */ "critical PMIC temperature",
 40	/* bit 2 */ "critical system temperature",
 41	/* bit 3 */ "critical battery temperature",
 42	/* bit 4 */ "VSYS under voltage",
 43	/* bit 5 */ "VSYS over voltage",
 44	/* bit 6 */ "battery removal",
 45	NULL,
 46};
 47
 48static const char * const pwrsrc_resetsrc1_info[] = {
 49	/* bit 0 */ "VCRIT threshold",
 50	/* bit 1 */ "BATID reporting battery removal",
 51	/* bit 2 */ "user pressing the power button",
 52	NULL,
 53};
 54
 55static const char * const pwrsrc_wakesrc_info[] = {
 56	/* bit 0 */ "user pressing the power button",
 57	/* bit 1 */ "a battery insertion",
 58	/* bit 2 */ "a USB charger insertion",
 59	/* bit 3 */ "an adapter insertion",
 60	NULL,
 61};
 62
 63static void crc_pwrsrc_log(struct seq_file *seq, const char *prefix,
 64			   const char * const *info, unsigned int reg_val)
 65{
 66	int i;
 67
 68	for (i = 0; info[i]; i++) {
 69		if (reg_val & BIT(i))
 70			seq_printf(seq, "%s by %s\n", prefix, info[i]);
 71	}
 72}
 73
 74static int pwrsrc_show(struct seq_file *seq, void *unused)
 75{
 76	struct crc_pwrsrc_data *data = seq->private;
 77	unsigned int reg_val;
 78	int ret;
 79
 80	ret = regmap_read(data->regmap, CRYSTALCOVE_SPWRSRC_REG, &reg_val);
 81	if (ret)
 82		return ret;
 83
 84	crc_pwrsrc_log(seq, "System powered", pwrsrc_pwrsrc_info, reg_val);
 85	return 0;
 86}
 87
 88static int resetsrc_show(struct seq_file *seq, void *unused)
 89{
 90	struct crc_pwrsrc_data *data = seq->private;
 91
 92	crc_pwrsrc_log(seq, "Last shutdown caused", pwrsrc_resetsrc0_info, data->resetsrc0);
 93	crc_pwrsrc_log(seq, "Last shutdown caused", pwrsrc_resetsrc1_info, data->resetsrc1);
 94	return 0;
 95}
 96
 97static int wakesrc_show(struct seq_file *seq, void *unused)
 98{
 99	struct crc_pwrsrc_data *data = seq->private;
100
101	crc_pwrsrc_log(seq, "Last wake caused", pwrsrc_wakesrc_info, data->wakesrc);
102	return 0;
103}
104
105DEFINE_SHOW_ATTRIBUTE(pwrsrc);
106DEFINE_SHOW_ATTRIBUTE(resetsrc);
107DEFINE_SHOW_ATTRIBUTE(wakesrc);
108
109static int crc_pwrsrc_read_and_clear(struct crc_pwrsrc_data *data,
110				     unsigned int reg, unsigned int *val)
111{
112	int ret;
113
114	ret = regmap_read(data->regmap, reg, val);
115	if (ret)
116		return ret;
117
118	return regmap_write(data->regmap, reg, *val);
119}
120
121static int crc_pwrsrc_probe(struct platform_device *pdev)
122{
123	struct intel_soc_pmic *pmic = dev_get_drvdata(pdev->dev.parent);
124	struct crc_pwrsrc_data *data;
125	int ret;
126
127	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
128	if (!data)
129		return -ENOMEM;
130
131	data->regmap = pmic->regmap;
132
133	/*
134	 * Read + clear resetsrc0/1 and wakesrc now, so that they get
135	 * cleared even if the debugfs interface is never used.
136	 *
137	 * Properly clearing the wakesrc is important, leaving bit 0 of it
138	 * set turns reboot into poweroff on some tablets.
139	 */
140	ret = crc_pwrsrc_read_and_clear(data, CRYSTALCOVE_RESETSRC0_REG, &data->resetsrc0);
141	if (ret)
142		return ret;
143
144	ret = crc_pwrsrc_read_and_clear(data, CRYSTALCOVE_RESETSRC1_REG, &data->resetsrc1);
145	if (ret)
146		return ret;
147
148	ret = crc_pwrsrc_read_and_clear(data, CRYSTALCOVE_WAKESRC_REG, &data->wakesrc);
149	if (ret)
150		return ret;
151
152	data->debug_dentry = debugfs_create_dir(KBUILD_MODNAME, NULL);
153	debugfs_create_file("pwrsrc", 0444, data->debug_dentry, data, &pwrsrc_fops);
154	debugfs_create_file("resetsrc", 0444, data->debug_dentry, data, &resetsrc_fops);
155	debugfs_create_file("wakesrc", 0444, data->debug_dentry, data, &wakesrc_fops);
156
157	platform_set_drvdata(pdev, data);
158	return 0;
159}
160
161static void crc_pwrsrc_remove(struct platform_device *pdev)
162{
163	struct crc_pwrsrc_data *data = platform_get_drvdata(pdev);
164
165	debugfs_remove_recursive(data->debug_dentry);
166}
167
168static struct platform_driver crc_pwrsrc_driver = {
169	.probe = crc_pwrsrc_probe,
170	.remove_new = crc_pwrsrc_remove,
171	.driver = {
172		.name = "crystal_cove_pwrsrc",
173	},
174};
175module_platform_driver(crc_pwrsrc_driver);
176
177MODULE_ALIAS("platform:crystal_cove_pwrsrc");
178MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
179MODULE_DESCRIPTION("Power-source driver for Bay Trail Crystal Cove PMIC");
180MODULE_LICENSE("GPL");