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 static int temp_limits[3] = { 55000, 60000, 65000 };
20 module_param_array(temp_limits, int, NULL, 0444);
21 MODULE_PARM_DESC(temp_limits,
22 "Millicelsius values above which the fan speed increases");
23
24 static int hysteresis = 3000;
25 module_param(hysteresis, int, 0444);
26 MODULE_PARM_DESC(hysteresis,
27 "Hysteresis in millicelsius before lowering the fan speed");
28
29 static int speed_on_ac = 2;
30 module_param(speed_on_ac, int, 0444);
31 MODULE_PARM_DESC(speed_on_ac,
32 "minimum fan speed to allow when system is powered by AC");
33
34 struct gpd_pocket_fan_data {
35 struct device *dev;
36 struct thermal_zone_device *dts0;
37 struct thermal_zone_device *dts1;
38 struct gpio_desc *gpio0;
39 struct gpio_desc *gpio1;
40 struct delayed_work work;
41 int last_speed;
42 };
43
gpd_pocket_fan_set_speed(struct gpd_pocket_fan_data * fan,int speed)44 static void gpd_pocket_fan_set_speed(struct gpd_pocket_fan_data *fan, int speed)
45 {
46 if (speed == fan->last_speed)
47 return;
48
49 gpiod_direction_output(fan->gpio0, !!(speed & 1));
50 gpiod_direction_output(fan->gpio1, !!(speed & 2));
51
52 fan->last_speed = speed;
53 }
54
gpd_pocket_fan_min_speed(void)55 static int gpd_pocket_fan_min_speed(void)
56 {
57 if (power_supply_is_system_supplied())
58 return speed_on_ac;
59 else
60 return 0;
61 }
62
gpd_pocket_fan_worker(struct work_struct * work)63 static void gpd_pocket_fan_worker(struct work_struct *work)
64 {
65 struct gpd_pocket_fan_data *fan =
66 container_of(work, struct gpd_pocket_fan_data, work.work);
67 int t0, t1, temp, speed, min_speed, i;
68
69 if (thermal_zone_get_temp(fan->dts0, &t0) ||
70 thermal_zone_get_temp(fan->dts1, &t1)) {
71 dev_warn(fan->dev, "Error getting temperature\n");
72 speed = MAX_SPEED;
73 goto set_speed;
74 }
75
76 temp = max(t0, t1);
77
78 speed = fan->last_speed;
79 min_speed = gpd_pocket_fan_min_speed();
80
81 /* Determine minimum speed */
82 for (i = min_speed; i < ARRAY_SIZE(temp_limits); i++) {
83 if (temp < temp_limits[i])
84 break;
85 }
86 if (speed < i)
87 speed = i;
88
89 /* Use hysteresis before lowering speed again */
90 for (i = min_speed; i < ARRAY_SIZE(temp_limits); i++) {
91 if (temp <= (temp_limits[i] - hysteresis))
92 break;
93 }
94 if (speed > i)
95 speed = i;
96
97 if (fan->last_speed <= 0 && speed)
98 speed = MAX_SPEED; /* kick start motor */
99
100 set_speed:
101 gpd_pocket_fan_set_speed(fan, speed);
102
103 /* When mostly idle (low temp/speed), slow down the poll interval. */
104 queue_delayed_work(system_wq, &fan->work,
105 msecs_to_jiffies(4000 / (speed + 1)));
106 }
107
gpd_pocket_fan_force_update(struct gpd_pocket_fan_data * fan)108 static void gpd_pocket_fan_force_update(struct gpd_pocket_fan_data *fan)
109 {
110 fan->last_speed = -1;
111 mod_delayed_work(system_wq, &fan->work, 0);
112 }
113
gpd_pocket_fan_probe(struct platform_device * pdev)114 static int gpd_pocket_fan_probe(struct platform_device *pdev)
115 {
116 struct gpd_pocket_fan_data *fan;
117 int i;
118
119 for (i = 0; i < ARRAY_SIZE(temp_limits); i++) {
120 if (temp_limits[i] < 40000 || temp_limits[i] > 70000) {
121 dev_err(&pdev->dev, "Invalid temp-limit %d (must be between 40000 and 70000)\n",
122 temp_limits[i]);
123 return -EINVAL;
124 }
125 }
126 if (hysteresis < 1000 || hysteresis > 10000) {
127 dev_err(&pdev->dev, "Invalid hysteresis %d (must be between 1000 and 10000)\n",
128 hysteresis);
129 return -EINVAL;
130 }
131 if (speed_on_ac < 0 || speed_on_ac > MAX_SPEED) {
132 dev_err(&pdev->dev, "Invalid speed_on_ac %d (must be between 0 and 3)\n",
133 speed_on_ac);
134 return -EINVAL;
135 }
136
137 fan = devm_kzalloc(&pdev->dev, sizeof(*fan), GFP_KERNEL);
138 if (!fan)
139 return -ENOMEM;
140
141 fan->dev = &pdev->dev;
142 INIT_DELAYED_WORK(&fan->work, gpd_pocket_fan_worker);
143
144 /* Note this returns a "weak" reference which we don't need to free */
145 fan->dts0 = thermal_zone_get_zone_by_name("soc_dts0");
146 if (IS_ERR(fan->dts0))
147 return -EPROBE_DEFER;
148
149 fan->dts1 = thermal_zone_get_zone_by_name("soc_dts1");
150 if (IS_ERR(fan->dts1))
151 return -EPROBE_DEFER;
152
153 fan->gpio0 = devm_gpiod_get_index(fan->dev, NULL, 0, GPIOD_ASIS);
154 if (IS_ERR(fan->gpio0))
155 return PTR_ERR(fan->gpio0);
156
157 fan->gpio1 = devm_gpiod_get_index(fan->dev, NULL, 1, GPIOD_ASIS);
158 if (IS_ERR(fan->gpio1))
159 return PTR_ERR(fan->gpio1);
160
161 gpd_pocket_fan_force_update(fan);
162
163 platform_set_drvdata(pdev, fan);
164 return 0;
165 }
166
gpd_pocket_fan_remove(struct platform_device * pdev)167 static int gpd_pocket_fan_remove(struct platform_device *pdev)
168 {
169 struct gpd_pocket_fan_data *fan = platform_get_drvdata(pdev);
170
171 cancel_delayed_work_sync(&fan->work);
172 return 0;
173 }
174
175 #ifdef CONFIG_PM_SLEEP
gpd_pocket_fan_suspend(struct device * dev)176 static int gpd_pocket_fan_suspend(struct device *dev)
177 {
178 struct gpd_pocket_fan_data *fan = dev_get_drvdata(dev);
179
180 cancel_delayed_work_sync(&fan->work);
181 gpd_pocket_fan_set_speed(fan, gpd_pocket_fan_min_speed());
182 return 0;
183 }
184
gpd_pocket_fan_resume(struct device * dev)185 static int gpd_pocket_fan_resume(struct device *dev)
186 {
187 struct gpd_pocket_fan_data *fan = dev_get_drvdata(dev);
188
189 gpd_pocket_fan_force_update(fan);
190 return 0;
191 }
192 #endif
193 static SIMPLE_DEV_PM_OPS(gpd_pocket_fan_pm_ops,
194 gpd_pocket_fan_suspend,
195 gpd_pocket_fan_resume);
196
197 static struct acpi_device_id gpd_pocket_fan_acpi_match[] = {
198 { "FAN02501" },
199 {},
200 };
201 MODULE_DEVICE_TABLE(acpi, gpd_pocket_fan_acpi_match);
202
203 static struct platform_driver gpd_pocket_fan_driver = {
204 .probe = gpd_pocket_fan_probe,
205 .remove = gpd_pocket_fan_remove,
206 .driver = {
207 .name = "gpd_pocket_fan",
208 .acpi_match_table = gpd_pocket_fan_acpi_match,
209 .pm = &gpd_pocket_fan_pm_ops,
210 },
211 };
212
213 module_platform_driver(gpd_pocket_fan_driver);
214 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com");
215 MODULE_DESCRIPTION("GPD pocket fan driver");
216 MODULE_LICENSE("GPL");
217
