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