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 
28 static int temp_limits[3] = {
29 	TEMP_LIMIT0_DEFAULT, TEMP_LIMIT1_DEFAULT, TEMP_LIMIT2_DEFAULT,
30 };
31 module_param_array(temp_limits, int, NULL, 0444);
32 MODULE_PARM_DESC(temp_limits,
33 		 "Millicelsius values above which the fan speed increases");
34 
35 static int hysteresis = HYSTERESIS_DEFAULT;
36 module_param(hysteresis, int, 0444);
37 MODULE_PARM_DESC(hysteresis,
38 		 "Hysteresis in millicelsius before lowering the fan speed");
39 
40 static int speed_on_ac = SPEED_ON_AC_DEFAULT;
41 module_param(speed_on_ac, int, 0444);
42 MODULE_PARM_DESC(speed_on_ac,
43 		 "minimum fan speed to allow when system is powered by AC");
44 
45 struct 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 
gpd_pocket_fan_set_speed(struct gpd_pocket_fan_data * fan,int speed)55 static 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 
gpd_pocket_fan_min_speed(void)66 static 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 
gpd_pocket_fan_worker(struct work_struct * work)74 static 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 
111 set_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 
gpd_pocket_fan_force_update(struct gpd_pocket_fan_data * fan)119 static 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 
gpd_pocket_fan_probe(struct platform_device * pdev)125 static 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
gpd_pocket_fan_suspend(struct device * dev)185 static 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 
gpd_pocket_fan_resume(struct device * dev)194 static 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
202 static SIMPLE_DEV_PM_OPS(gpd_pocket_fan_pm_ops,
203 			 gpd_pocket_fan_suspend,
204 			 gpd_pocket_fan_resume);
205 
206 static struct acpi_device_id gpd_pocket_fan_acpi_match[] = {
207 	{ "FAN02501" },
208 	{},
209 };
210 MODULE_DEVICE_TABLE(acpi, gpd_pocket_fan_acpi_match);
211 
212 static 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 
221 module_platform_driver(gpd_pocket_fan_driver);
222 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com");
223 MODULE_DESCRIPTION("GPD pocket fan driver");
224 MODULE_LICENSE("GPL");
225