1 /*
2  * Thermal device driver for DA9062 and DA9061
3  * Copyright (C) 2017  Dialog Semiconductor
4  *
5  * This program is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU General Public License
7  * as published by the Free Software Foundation; either version 2
8  * of the License, or (at your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  */
15 
16 /* When over-temperature is reached, an interrupt from the device will be
17  * triggered. Following this event the interrupt will be disabled and
18  * periodic transmission of uevents (HOT trip point) should define the
19  * first level of temperature supervision. It is expected that any final
20  * implementation of the thermal driver will include a .notify() function
21  * to implement these uevents to userspace.
22  *
23  * These uevents are intended to indicate non-invasive temperature control
24  * of the system, where the necessary measures for cooling are the
25  * responsibility of the host software. Once the temperature falls again,
26  * the IRQ is re-enabled so the start of a new over-temperature event can
27  * be detected without constant software monitoring.
28  */
29 
30 #include <linux/errno.h>
31 #include <linux/interrupt.h>
32 #include <linux/module.h>
33 #include <linux/of.h>
34 #include <linux/platform_device.h>
35 #include <linux/regmap.h>
36 #include <linux/thermal.h>
37 #include <linux/workqueue.h>
38 
39 #include <linux/mfd/da9062/core.h>
40 #include <linux/mfd/da9062/registers.h>
41 
42 /* Minimum, maximum and default polling millisecond periods are provided
43  * here as an example. It is expected that any final implementation to also
44  * include a modification of these settings to match the required
45  * application.
46  */
47 #define DA9062_DEFAULT_POLLING_MS_PERIOD	3000
48 #define DA9062_MAX_POLLING_MS_PERIOD		10000
49 #define DA9062_MIN_POLLING_MS_PERIOD		1000
50 
51 #define DA9062_MILLI_CELSIUS(t)			((t) * 1000)
52 
53 struct da9062_thermal_config {
54 	const char *name;
55 };
56 
57 struct da9062_thermal {
58 	struct da9062 *hw;
59 	struct delayed_work work;
60 	struct thermal_zone_device *zone;
61 	enum thermal_device_mode mode;
62 	struct mutex lock; /* protection for da9062_thermal temperature */
63 	int temperature;
64 	int irq;
65 	const struct da9062_thermal_config *config;
66 	struct device *dev;
67 };
68 
69 static void da9062_thermal_poll_on(struct work_struct *work)
70 {
71 	struct da9062_thermal *thermal = container_of(work,
72 						struct da9062_thermal,
73 						work.work);
74 	unsigned long delay;
75 	unsigned int val;
76 	int ret;
77 
78 	/* clear E_TEMP */
79 	ret = regmap_write(thermal->hw->regmap,
80 			   DA9062AA_EVENT_B,
81 			   DA9062AA_E_TEMP_MASK);
82 	if (ret < 0) {
83 		dev_err(thermal->dev,
84 			"Cannot clear the TJUNC temperature status\n");
85 		goto err_enable_irq;
86 	}
87 
88 	/* Now read E_TEMP again: it is acting like a status bit.
89 	 * If over-temperature, then this status will be true.
90 	 * If not over-temperature, this status will be false.
91 	 */
92 	ret = regmap_read(thermal->hw->regmap,
93 			  DA9062AA_EVENT_B,
94 			  &val);
95 	if (ret < 0) {
96 		dev_err(thermal->dev,
97 			"Cannot check the TJUNC temperature status\n");
98 		goto err_enable_irq;
99 	}
100 
101 	if (val & DA9062AA_E_TEMP_MASK) {
102 		mutex_lock(&thermal->lock);
103 		thermal->temperature = DA9062_MILLI_CELSIUS(125);
104 		mutex_unlock(&thermal->lock);
105 		thermal_zone_device_update(thermal->zone,
106 					   THERMAL_EVENT_UNSPECIFIED);
107 
108 		delay = msecs_to_jiffies(thermal->zone->passive_delay);
109 		queue_delayed_work(system_freezable_wq, &thermal->work, delay);
110 		return;
111 	}
112 
113 	mutex_lock(&thermal->lock);
114 	thermal->temperature = DA9062_MILLI_CELSIUS(0);
115 	mutex_unlock(&thermal->lock);
116 	thermal_zone_device_update(thermal->zone,
117 				   THERMAL_EVENT_UNSPECIFIED);
118 
119 err_enable_irq:
120 	enable_irq(thermal->irq);
121 }
122 
123 static irqreturn_t da9062_thermal_irq_handler(int irq, void *data)
124 {
125 	struct da9062_thermal *thermal = data;
126 
127 	disable_irq_nosync(thermal->irq);
128 	queue_delayed_work(system_freezable_wq, &thermal->work, 0);
129 
130 	return IRQ_HANDLED;
131 }
132 
133 static int da9062_thermal_get_mode(struct thermal_zone_device *z,
134 				   enum thermal_device_mode *mode)
135 {
136 	struct da9062_thermal *thermal = z->devdata;
137 	*mode = thermal->mode;
138 	return 0;
139 }
140 
141 static int da9062_thermal_get_trip_type(struct thermal_zone_device *z,
142 					int trip,
143 					enum thermal_trip_type *type)
144 {
145 	struct da9062_thermal *thermal = z->devdata;
146 
147 	switch (trip) {
148 	case 0:
149 		*type = THERMAL_TRIP_HOT;
150 		break;
151 	default:
152 		dev_err(thermal->dev,
153 			"Driver does not support more than 1 trip-wire\n");
154 		return -EINVAL;
155 	}
156 
157 	return 0;
158 }
159 
160 static int da9062_thermal_get_trip_temp(struct thermal_zone_device *z,
161 					int trip,
162 					int *temp)
163 {
164 	struct da9062_thermal *thermal = z->devdata;
165 
166 	switch (trip) {
167 	case 0:
168 		*temp = DA9062_MILLI_CELSIUS(125);
169 		break;
170 	default:
171 		dev_err(thermal->dev,
172 			"Driver does not support more than 1 trip-wire\n");
173 		return -EINVAL;
174 	}
175 
176 	return 0;
177 }
178 
179 static int da9062_thermal_get_temp(struct thermal_zone_device *z,
180 				   int *temp)
181 {
182 	struct da9062_thermal *thermal = z->devdata;
183 
184 	mutex_lock(&thermal->lock);
185 	*temp = thermal->temperature;
186 	mutex_unlock(&thermal->lock);
187 
188 	return 0;
189 }
190 
191 static struct thermal_zone_device_ops da9062_thermal_ops = {
192 	.get_temp	= da9062_thermal_get_temp,
193 	.get_mode	= da9062_thermal_get_mode,
194 	.get_trip_type	= da9062_thermal_get_trip_type,
195 	.get_trip_temp	= da9062_thermal_get_trip_temp,
196 };
197 
198 static const struct da9062_thermal_config da9062_config = {
199 	.name = "da9062-thermal",
200 };
201 
202 static const struct of_device_id da9062_compatible_reg_id_table[] = {
203 	{ .compatible = "dlg,da9062-thermal", .data = &da9062_config },
204 	{ },
205 };
206 
207 MODULE_DEVICE_TABLE(of, da9062_compatible_reg_id_table);
208 
209 static int da9062_thermal_probe(struct platform_device *pdev)
210 {
211 	struct da9062 *chip = dev_get_drvdata(pdev->dev.parent);
212 	struct da9062_thermal *thermal;
213 	unsigned int pp_tmp = DA9062_DEFAULT_POLLING_MS_PERIOD;
214 	const struct of_device_id *match;
215 	int ret = 0;
216 
217 	match = of_match_node(da9062_compatible_reg_id_table,
218 			      pdev->dev.of_node);
219 	if (!match)
220 		return -ENXIO;
221 
222 	if (pdev->dev.of_node) {
223 		if (!of_property_read_u32(pdev->dev.of_node,
224 					  "polling-delay-passive",
225 					  &pp_tmp)) {
226 			if (pp_tmp < DA9062_MIN_POLLING_MS_PERIOD ||
227 			    pp_tmp > DA9062_MAX_POLLING_MS_PERIOD) {
228 				dev_warn(&pdev->dev,
229 					 "Out-of-range polling period %d ms\n",
230 					 pp_tmp);
231 				pp_tmp = DA9062_DEFAULT_POLLING_MS_PERIOD;
232 			}
233 		}
234 	}
235 
236 	thermal = devm_kzalloc(&pdev->dev, sizeof(struct da9062_thermal),
237 			       GFP_KERNEL);
238 	if (!thermal) {
239 		ret = -ENOMEM;
240 		goto err;
241 	}
242 
243 	thermal->config = match->data;
244 	thermal->hw = chip;
245 	thermal->mode = THERMAL_DEVICE_ENABLED;
246 	thermal->dev = &pdev->dev;
247 
248 	INIT_DELAYED_WORK(&thermal->work, da9062_thermal_poll_on);
249 	mutex_init(&thermal->lock);
250 
251 	thermal->zone = thermal_zone_device_register(thermal->config->name,
252 					1, 0, thermal,
253 					&da9062_thermal_ops, NULL, pp_tmp,
254 					0);
255 	if (IS_ERR(thermal->zone)) {
256 		dev_err(&pdev->dev, "Cannot register thermal zone device\n");
257 		ret = PTR_ERR(thermal->zone);
258 		goto err;
259 	}
260 
261 	dev_dbg(&pdev->dev,
262 		"TJUNC temperature polling period set at %d ms\n",
263 		thermal->zone->passive_delay);
264 
265 	ret = platform_get_irq_byname(pdev, "THERMAL");
266 	if (ret < 0) {
267 		dev_err(&pdev->dev, "Failed to get platform IRQ.\n");
268 		goto err_zone;
269 	}
270 	thermal->irq = ret;
271 
272 	ret = request_threaded_irq(thermal->irq, NULL,
273 				   da9062_thermal_irq_handler,
274 				   IRQF_TRIGGER_LOW | IRQF_ONESHOT,
275 				   "THERMAL", thermal);
276 	if (ret) {
277 		dev_err(&pdev->dev,
278 			"Failed to request thermal device IRQ.\n");
279 		goto err_zone;
280 	}
281 
282 	platform_set_drvdata(pdev, thermal);
283 	return 0;
284 
285 err_zone:
286 	thermal_zone_device_unregister(thermal->zone);
287 err:
288 	return ret;
289 }
290 
291 static int da9062_thermal_remove(struct platform_device *pdev)
292 {
293 	struct	da9062_thermal *thermal = platform_get_drvdata(pdev);
294 
295 	free_irq(thermal->irq, thermal);
296 	cancel_delayed_work_sync(&thermal->work);
297 	thermal_zone_device_unregister(thermal->zone);
298 	return 0;
299 }
300 
301 static struct platform_driver da9062_thermal_driver = {
302 	.probe	= da9062_thermal_probe,
303 	.remove	= da9062_thermal_remove,
304 	.driver	= {
305 		.name	= "da9062-thermal",
306 		.of_match_table = da9062_compatible_reg_id_table,
307 	},
308 };
309 
310 module_platform_driver(da9062_thermal_driver);
311 
312 MODULE_AUTHOR("Steve Twiss");
313 MODULE_DESCRIPTION("Thermal TJUNC device driver for Dialog DA9062 and DA9061");
314 MODULE_LICENSE("GPL");
315 MODULE_ALIAS("platform:da9062-thermal");
316