1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * GPD Pocket fan controller driver
4 *
5 * Copyright (C) 2017 Hans de Goede <hdegoede@redhat.com>
6 */
7
8#include <linux/acpi.h>
9#include <linux/gpio/consumer.h>
10#include <linux/module.h>
11#include <linux/moduleparam.h>
12#include <linux/platform_device.h>
13#include <linux/power_supply.h>
14#include <linux/thermal.h>
15#include <linux/workqueue.h>
16
17#define MAX_SPEED 3
18
19#define TEMP_LIMIT0_DEFAULT	55000
20#define TEMP_LIMIT1_DEFAULT	60000
21#define TEMP_LIMIT2_DEFAULT	65000
22
23#define HYSTERESIS_DEFAULT	3000
24
25#define SPEED_ON_AC_DEFAULT	2
26
27static int temp_limits[3] = {
28	TEMP_LIMIT0_DEFAULT, TEMP_LIMIT1_DEFAULT, TEMP_LIMIT2_DEFAULT,
29};
30module_param_array(temp_limits, int, NULL, 0444);
31MODULE_PARM_DESC(temp_limits,
32		 "Millicelsius values above which the fan speed increases");
33
34static int hysteresis = HYSTERESIS_DEFAULT;
35module_param(hysteresis, int, 0444);
36MODULE_PARM_DESC(hysteresis,
37		 "Hysteresis in millicelsius before lowering the fan speed");
38
39static int speed_on_ac = SPEED_ON_AC_DEFAULT;
40module_param(speed_on_ac, int, 0444);
41MODULE_PARM_DESC(speed_on_ac,
42		 "minimum fan speed to allow when system is powered by AC");
43
44struct gpd_pocket_fan_data {
45	struct device *dev;
46	struct thermal_zone_device *dts0;
47	struct thermal_zone_device *dts1;
48	struct gpio_desc *gpio0;
49	struct gpio_desc *gpio1;
50	struct delayed_work work;
51	int last_speed;
52};
53
54static void gpd_pocket_fan_set_speed(struct gpd_pocket_fan_data *fan, int speed)
55{
56	if (speed == fan->last_speed)
57		return;
58
59	gpiod_direction_output(fan->gpio0, !!(speed & 1));
60	gpiod_direction_output(fan->gpio1, !!(speed & 2));
61
62	fan->last_speed = speed;
63}
64
65static int gpd_pocket_fan_min_speed(void)
66{
67	if (power_supply_is_system_supplied())
68		return speed_on_ac;
69	else
70		return 0;
71}
72
73static void gpd_pocket_fan_worker(struct work_struct *work)
74{
75	struct gpd_pocket_fan_data *fan =
76		container_of(work, struct gpd_pocket_fan_data, work.work);
77	int t0, t1, temp, speed, min_speed, i;
78
79	if (thermal_zone_get_temp(fan->dts0, &t0) ||
80	    thermal_zone_get_temp(fan->dts1, &t1)) {
81		dev_warn(fan->dev, "Error getting temperature\n");
82		speed = MAX_SPEED;
83		goto set_speed;
84	}
85
86	temp = max(t0, t1);
87
88	speed = fan->last_speed;
89	min_speed = gpd_pocket_fan_min_speed();
90
91	/* Determine minimum speed */
92	for (i = min_speed; i < ARRAY_SIZE(temp_limits); i++) {
93		if (temp < temp_limits[i])
94			break;
95	}
96	if (speed < i)
97		speed = i;
98
99	/* Use hysteresis before lowering speed again */
100	for (i = min_speed; i < ARRAY_SIZE(temp_limits); i++) {
101		if (temp <= (temp_limits[i] - hysteresis))
102			break;
103	}
104	if (speed > i)
105		speed = i;
106
107	if (fan->last_speed <= 0 && speed)
108		speed = MAX_SPEED; /* kick start motor */
109
110set_speed:
111	gpd_pocket_fan_set_speed(fan, speed);
112
113	/* When mostly idle (low temp/speed), slow down the poll interval. */
114	queue_delayed_work(system_wq, &fan->work,
115			   msecs_to_jiffies(4000 / (speed + 1)));
116}
117
118static void gpd_pocket_fan_force_update(struct gpd_pocket_fan_data *fan)
119{
120	fan->last_speed = -1;
121	mod_delayed_work(system_wq, &fan->work, 0);
122}
123
124static int gpd_pocket_fan_probe(struct platform_device *pdev)
125{
126	struct gpd_pocket_fan_data *fan;
127	int i;
128
129	for (i = 0; i < ARRAY_SIZE(temp_limits); i++) {
130		if (temp_limits[i] < 20000 || temp_limits[i] > 90000) {
131			dev_err(&pdev->dev, "Invalid temp-limit %d (must be between 20000 and 90000)\n",
132				temp_limits[i]);
133			temp_limits[0] = TEMP_LIMIT0_DEFAULT;
134			temp_limits[1] = TEMP_LIMIT1_DEFAULT;
135			temp_limits[2] = TEMP_LIMIT2_DEFAULT;
136			break;
137		}
138	}
139	if (hysteresis < 1000 || hysteresis > 10000) {
140		dev_err(&pdev->dev, "Invalid hysteresis %d (must be between 1000 and 10000)\n",
141			hysteresis);
142		hysteresis = HYSTERESIS_DEFAULT;
143	}
144	if (speed_on_ac < 0 || speed_on_ac > MAX_SPEED) {
145		dev_err(&pdev->dev, "Invalid speed_on_ac %d (must be between 0 and 3)\n",
146			speed_on_ac);
147		speed_on_ac = SPEED_ON_AC_DEFAULT;
148	}
149
150	fan = devm_kzalloc(&pdev->dev, sizeof(*fan), GFP_KERNEL);
151	if (!fan)
152		return -ENOMEM;
153
154	fan->dev = &pdev->dev;
155	INIT_DELAYED_WORK(&fan->work, gpd_pocket_fan_worker);
156
157	/* Note this returns a "weak" reference which we don't need to free */
158	fan->dts0 = thermal_zone_get_zone_by_name("soc_dts0");
159	if (IS_ERR(fan->dts0))
160		return -EPROBE_DEFER;
161
162	fan->dts1 = thermal_zone_get_zone_by_name("soc_dts1");
163	if (IS_ERR(fan->dts1))
164		return -EPROBE_DEFER;
165
166	fan->gpio0 = devm_gpiod_get_index(fan->dev, NULL, 0, GPIOD_ASIS);
167	if (IS_ERR(fan->gpio0))
168		return PTR_ERR(fan->gpio0);
169
170	fan->gpio1 = devm_gpiod_get_index(fan->dev, NULL, 1, GPIOD_ASIS);
171	if (IS_ERR(fan->gpio1))
172		return PTR_ERR(fan->gpio1);
173
174	gpd_pocket_fan_force_update(fan);
175
176	platform_set_drvdata(pdev, fan);
177	return 0;
178}
179
180static int gpd_pocket_fan_remove(struct platform_device *pdev)
181{
182	struct gpd_pocket_fan_data *fan = platform_get_drvdata(pdev);
183
184	cancel_delayed_work_sync(&fan->work);
185	return 0;
186}
187
188#ifdef CONFIG_PM_SLEEP
189static int gpd_pocket_fan_suspend(struct device *dev)
190{
191	struct gpd_pocket_fan_data *fan = dev_get_drvdata(dev);
192
193	cancel_delayed_work_sync(&fan->work);
194	gpd_pocket_fan_set_speed(fan, gpd_pocket_fan_min_speed());
195	return 0;
196}
197
198static int gpd_pocket_fan_resume(struct device *dev)
199{
200	struct gpd_pocket_fan_data *fan = dev_get_drvdata(dev);
201
202	gpd_pocket_fan_force_update(fan);
203	return 0;
204}
205#endif
206static SIMPLE_DEV_PM_OPS(gpd_pocket_fan_pm_ops,
207			 gpd_pocket_fan_suspend,
208			 gpd_pocket_fan_resume);
209
210static struct acpi_device_id gpd_pocket_fan_acpi_match[] = {
211	{ "FAN02501" },
212	{},
213};
214MODULE_DEVICE_TABLE(acpi, gpd_pocket_fan_acpi_match);
215
216static struct platform_driver gpd_pocket_fan_driver = {
217	.probe	= gpd_pocket_fan_probe,
218	.remove	= gpd_pocket_fan_remove,
219	.driver	= {
220		.name			= "gpd_pocket_fan",
221		.acpi_match_table	= gpd_pocket_fan_acpi_match,
222		.pm			= &gpd_pocket_fan_pm_ops,
223	 },
224};
225
226module_platform_driver(gpd_pocket_fan_driver);
227MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com");
228MODULE_DESCRIPTION("GPD pocket fan driver");
229MODULE_LICENSE("GPL");
230