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
