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 		 "Milli-celcius 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 milli-celcius 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 
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 
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 
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 
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 
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 
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
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 
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