1 /*
2 * STMicroelectronics uvis25 sensor driver
3 *
4 * Copyright 2017 STMicroelectronics Inc.
5 *
6 * Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>
7 *
8 * Licensed under the GPL-2.
9 */
10
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/device.h>
14 #include <linux/iio/sysfs.h>
15 #include <linux/delay.h>
16 #include <linux/pm.h>
17 #include <linux/interrupt.h>
18 #include <linux/irqreturn.h>
19 #include <linux/iio/trigger.h>
20 #include <linux/iio/trigger_consumer.h>
21 #include <linux/iio/triggered_buffer.h>
22 #include <linux/iio/buffer.h>
23 #include <linux/regmap.h>
24
25 #include "st_uvis25.h"
26
27 #define ST_UVIS25_REG_WHOAMI_ADDR 0x0f
28 #define ST_UVIS25_REG_WHOAMI_VAL 0xca
29 #define ST_UVIS25_REG_CTRL1_ADDR 0x20
30 #define ST_UVIS25_REG_ODR_MASK BIT(0)
31 #define ST_UVIS25_REG_BDU_MASK BIT(1)
32 #define ST_UVIS25_REG_CTRL2_ADDR 0x21
33 #define ST_UVIS25_REG_BOOT_MASK BIT(7)
34 #define ST_UVIS25_REG_CTRL3_ADDR 0x22
35 #define ST_UVIS25_REG_HL_MASK BIT(7)
36 #define ST_UVIS25_REG_STATUS_ADDR 0x27
37 #define ST_UVIS25_REG_UV_DA_MASK BIT(0)
38 #define ST_UVIS25_REG_OUT_ADDR 0x28
39
40 static const struct iio_chan_spec st_uvis25_channels[] = {
41 {
42 .type = IIO_UVINDEX,
43 .address = ST_UVIS25_REG_OUT_ADDR,
44 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
45 .scan_index = 0,
46 .scan_type = {
47 .sign = 'u',
48 .realbits = 8,
49 .storagebits = 8,
50 },
51 },
52 IIO_CHAN_SOFT_TIMESTAMP(1),
53 };
54
st_uvis25_check_whoami(struct st_uvis25_hw * hw)55 static int st_uvis25_check_whoami(struct st_uvis25_hw *hw)
56 {
57 int err, data;
58
59 err = regmap_read(hw->regmap, ST_UVIS25_REG_WHOAMI_ADDR, &data);
60 if (err < 0) {
61 dev_err(regmap_get_device(hw->regmap),
62 "failed to read whoami register\n");
63 return err;
64 }
65
66 if (data != ST_UVIS25_REG_WHOAMI_VAL) {
67 dev_err(regmap_get_device(hw->regmap),
68 "wrong whoami {%02x vs %02x}\n",
69 data, ST_UVIS25_REG_WHOAMI_VAL);
70 return -ENODEV;
71 }
72
73 return 0;
74 }
75
st_uvis25_set_enable(struct st_uvis25_hw * hw,bool enable)76 static int st_uvis25_set_enable(struct st_uvis25_hw *hw, bool enable)
77 {
78 int err;
79
80 err = regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL1_ADDR,
81 ST_UVIS25_REG_ODR_MASK, enable);
82 if (err < 0)
83 return err;
84
85 hw->enabled = enable;
86
87 return 0;
88 }
89
st_uvis25_read_oneshot(struct st_uvis25_hw * hw,u8 addr,int * val)90 static int st_uvis25_read_oneshot(struct st_uvis25_hw *hw, u8 addr, int *val)
91 {
92 int err;
93
94 err = st_uvis25_set_enable(hw, true);
95 if (err < 0)
96 return err;
97
98 msleep(1500);
99
100 /*
101 * in order to avoid possible race conditions with interrupt
102 * generation, disable the sensor first and then poll output
103 * register. That sequence guarantees the interrupt will be reset
104 * when irq line is unmasked
105 */
106 err = st_uvis25_set_enable(hw, false);
107 if (err < 0)
108 return err;
109
110 err = regmap_read(hw->regmap, addr, val);
111
112 return err < 0 ? err : IIO_VAL_INT;
113 }
114
st_uvis25_read_raw(struct iio_dev * iio_dev,struct iio_chan_spec const * ch,int * val,int * val2,long mask)115 static int st_uvis25_read_raw(struct iio_dev *iio_dev,
116 struct iio_chan_spec const *ch,
117 int *val, int *val2, long mask)
118 {
119 int ret;
120
121 ret = iio_device_claim_direct_mode(iio_dev);
122 if (ret)
123 return ret;
124
125 switch (mask) {
126 case IIO_CHAN_INFO_PROCESSED: {
127 struct st_uvis25_hw *hw = iio_priv(iio_dev);
128
129 /*
130 * mask irq line during oneshot read since the sensor
131 * does not export the capability to disable data-ready line
132 * in the register map and it is enabled by default.
133 * If the line is unmasked during read_raw() it will be set
134 * active and never reset since the trigger is disabled
135 */
136 if (hw->irq > 0)
137 disable_irq(hw->irq);
138 ret = st_uvis25_read_oneshot(hw, ch->address, val);
139 if (hw->irq > 0)
140 enable_irq(hw->irq);
141 break;
142 }
143 default:
144 ret = -EINVAL;
145 break;
146 }
147
148 iio_device_release_direct_mode(iio_dev);
149
150 return ret;
151 }
152
st_uvis25_trigger_handler_thread(int irq,void * private)153 static irqreturn_t st_uvis25_trigger_handler_thread(int irq, void *private)
154 {
155 struct st_uvis25_hw *hw = private;
156 int err, status;
157
158 err = regmap_read(hw->regmap, ST_UVIS25_REG_STATUS_ADDR, &status);
159 if (err < 0)
160 return IRQ_HANDLED;
161
162 if (!(status & ST_UVIS25_REG_UV_DA_MASK))
163 return IRQ_NONE;
164
165 iio_trigger_poll_chained(hw->trig);
166
167 return IRQ_HANDLED;
168 }
169
st_uvis25_allocate_trigger(struct iio_dev * iio_dev)170 static int st_uvis25_allocate_trigger(struct iio_dev *iio_dev)
171 {
172 struct st_uvis25_hw *hw = iio_priv(iio_dev);
173 struct device *dev = regmap_get_device(hw->regmap);
174 bool irq_active_low = false;
175 unsigned long irq_type;
176 int err;
177
178 irq_type = irqd_get_trigger_type(irq_get_irq_data(hw->irq));
179
180 switch (irq_type) {
181 case IRQF_TRIGGER_HIGH:
182 case IRQF_TRIGGER_RISING:
183 break;
184 case IRQF_TRIGGER_LOW:
185 case IRQF_TRIGGER_FALLING:
186 irq_active_low = true;
187 break;
188 default:
189 dev_info(dev, "mode %lx unsupported\n", irq_type);
190 return -EINVAL;
191 }
192
193 err = regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL3_ADDR,
194 ST_UVIS25_REG_HL_MASK, irq_active_low);
195 if (err < 0)
196 return err;
197
198 err = devm_request_threaded_irq(dev, hw->irq, NULL,
199 st_uvis25_trigger_handler_thread,
200 irq_type | IRQF_ONESHOT,
201 iio_dev->name, hw);
202 if (err) {
203 dev_err(dev, "failed to request trigger irq %d\n",
204 hw->irq);
205 return err;
206 }
207
208 hw->trig = devm_iio_trigger_alloc(dev, "%s-trigger",
209 iio_dev->name);
210 if (!hw->trig)
211 return -ENOMEM;
212
213 iio_trigger_set_drvdata(hw->trig, iio_dev);
214 hw->trig->dev.parent = dev;
215
216 return devm_iio_trigger_register(dev, hw->trig);
217 }
218
st_uvis25_buffer_preenable(struct iio_dev * iio_dev)219 static int st_uvis25_buffer_preenable(struct iio_dev *iio_dev)
220 {
221 return st_uvis25_set_enable(iio_priv(iio_dev), true);
222 }
223
st_uvis25_buffer_postdisable(struct iio_dev * iio_dev)224 static int st_uvis25_buffer_postdisable(struct iio_dev *iio_dev)
225 {
226 return st_uvis25_set_enable(iio_priv(iio_dev), false);
227 }
228
229 static const struct iio_buffer_setup_ops st_uvis25_buffer_ops = {
230 .preenable = st_uvis25_buffer_preenable,
231 .postenable = iio_triggered_buffer_postenable,
232 .predisable = iio_triggered_buffer_predisable,
233 .postdisable = st_uvis25_buffer_postdisable,
234 };
235
st_uvis25_buffer_handler_thread(int irq,void * p)236 static irqreturn_t st_uvis25_buffer_handler_thread(int irq, void *p)
237 {
238 u8 buffer[ALIGN(sizeof(u8), sizeof(s64)) + sizeof(s64)];
239 struct iio_poll_func *pf = p;
240 struct iio_dev *iio_dev = pf->indio_dev;
241 struct st_uvis25_hw *hw = iio_priv(iio_dev);
242 int err;
243
244 err = regmap_read(hw->regmap, ST_UVIS25_REG_OUT_ADDR, (int *)buffer);
245 if (err < 0)
246 goto out;
247
248 iio_push_to_buffers_with_timestamp(iio_dev, buffer,
249 iio_get_time_ns(iio_dev));
250
251 out:
252 iio_trigger_notify_done(hw->trig);
253
254 return IRQ_HANDLED;
255 }
256
st_uvis25_allocate_buffer(struct iio_dev * iio_dev)257 static int st_uvis25_allocate_buffer(struct iio_dev *iio_dev)
258 {
259 struct st_uvis25_hw *hw = iio_priv(iio_dev);
260
261 return devm_iio_triggered_buffer_setup(regmap_get_device(hw->regmap),
262 iio_dev, NULL,
263 st_uvis25_buffer_handler_thread,
264 &st_uvis25_buffer_ops);
265 }
266
267 static const struct iio_info st_uvis25_info = {
268 .read_raw = st_uvis25_read_raw,
269 };
270
st_uvis25_init_sensor(struct st_uvis25_hw * hw)271 static int st_uvis25_init_sensor(struct st_uvis25_hw *hw)
272 {
273 int err;
274
275 err = regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL2_ADDR,
276 ST_UVIS25_REG_BOOT_MASK, 1);
277 if (err < 0)
278 return err;
279
280 msleep(2000);
281
282 return regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL1_ADDR,
283 ST_UVIS25_REG_BDU_MASK, 1);
284 }
285
st_uvis25_probe(struct device * dev,int irq,struct regmap * regmap)286 int st_uvis25_probe(struct device *dev, int irq, struct regmap *regmap)
287 {
288 struct st_uvis25_hw *hw;
289 struct iio_dev *iio_dev;
290 int err;
291
292 iio_dev = devm_iio_device_alloc(dev, sizeof(*hw));
293 if (!iio_dev)
294 return -ENOMEM;
295
296 dev_set_drvdata(dev, (void *)iio_dev);
297
298 hw = iio_priv(iio_dev);
299 hw->irq = irq;
300 hw->regmap = regmap;
301
302 err = st_uvis25_check_whoami(hw);
303 if (err < 0)
304 return err;
305
306 iio_dev->modes = INDIO_DIRECT_MODE;
307 iio_dev->dev.parent = dev;
308 iio_dev->channels = st_uvis25_channels;
309 iio_dev->num_channels = ARRAY_SIZE(st_uvis25_channels);
310 iio_dev->name = ST_UVIS25_DEV_NAME;
311 iio_dev->info = &st_uvis25_info;
312
313 err = st_uvis25_init_sensor(hw);
314 if (err < 0)
315 return err;
316
317 if (hw->irq > 0) {
318 err = st_uvis25_allocate_buffer(iio_dev);
319 if (err < 0)
320 return err;
321
322 err = st_uvis25_allocate_trigger(iio_dev);
323 if (err)
324 return err;
325 }
326
327 return devm_iio_device_register(dev, iio_dev);
328 }
329 EXPORT_SYMBOL(st_uvis25_probe);
330
st_uvis25_suspend(struct device * dev)331 static int __maybe_unused st_uvis25_suspend(struct device *dev)
332 {
333 struct iio_dev *iio_dev = dev_get_drvdata(dev);
334 struct st_uvis25_hw *hw = iio_priv(iio_dev);
335
336 return regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL1_ADDR,
337 ST_UVIS25_REG_ODR_MASK, 0);
338 }
339
st_uvis25_resume(struct device * dev)340 static int __maybe_unused st_uvis25_resume(struct device *dev)
341 {
342 struct iio_dev *iio_dev = dev_get_drvdata(dev);
343 struct st_uvis25_hw *hw = iio_priv(iio_dev);
344
345 if (hw->enabled)
346 return regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL1_ADDR,
347 ST_UVIS25_REG_ODR_MASK, 1);
348
349 return 0;
350 }
351
352 const struct dev_pm_ops st_uvis25_pm_ops = {
353 SET_SYSTEM_SLEEP_PM_OPS(st_uvis25_suspend, st_uvis25_resume)
354 };
355 EXPORT_SYMBOL(st_uvis25_pm_ops);
356
357 MODULE_AUTHOR("Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>");
358 MODULE_DESCRIPTION("STMicroelectronics uvis25 sensor driver");
359 MODULE_LICENSE("GPL v2");
360
