1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * STMicroelectronics uvis25 sensor driver
4 *
5 * Copyright 2017 STMicroelectronics Inc.
6 *
7 * Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>
8 */
9
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/device.h>
13 #include <linux/iio/sysfs.h>
14 #include <linux/delay.h>
15 #include <linux/pm.h>
16 #include <linux/interrupt.h>
17 #include <linux/irqreturn.h>
18 #include <linux/iio/trigger.h>
19 #include <linux/iio/trigger_consumer.h>
20 #include <linux/iio/triggered_buffer.h>
21 #include <linux/iio/buffer.h>
22 #include <linux/regmap.h>
23
24 #include "st_uvis25.h"
25
26 #define ST_UVIS25_REG_WHOAMI_ADDR 0x0f
27 #define ST_UVIS25_REG_WHOAMI_VAL 0xca
28 #define ST_UVIS25_REG_CTRL1_ADDR 0x20
29 #define ST_UVIS25_REG_ODR_MASK BIT(0)
30 #define ST_UVIS25_REG_BDU_MASK BIT(1)
31 #define ST_UVIS25_REG_CTRL2_ADDR 0x21
32 #define ST_UVIS25_REG_BOOT_MASK BIT(7)
33 #define ST_UVIS25_REG_CTRL3_ADDR 0x22
34 #define ST_UVIS25_REG_HL_MASK BIT(7)
35 #define ST_UVIS25_REG_STATUS_ADDR 0x27
36 #define ST_UVIS25_REG_UV_DA_MASK BIT(0)
37 #define ST_UVIS25_REG_OUT_ADDR 0x28
38
39 static const struct iio_chan_spec st_uvis25_channels[] = {
40 {
41 .type = IIO_UVINDEX,
42 .address = ST_UVIS25_REG_OUT_ADDR,
43 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
44 .scan_index = 0,
45 .scan_type = {
46 .sign = 'u',
47 .realbits = 8,
48 .storagebits = 8,
49 },
50 },
51 IIO_CHAN_SOFT_TIMESTAMP(1),
52 };
53
st_uvis25_check_whoami(struct st_uvis25_hw * hw)54 static int st_uvis25_check_whoami(struct st_uvis25_hw *hw)
55 {
56 int err, data;
57
58 err = regmap_read(hw->regmap, ST_UVIS25_REG_WHOAMI_ADDR, &data);
59 if (err < 0) {
60 dev_err(regmap_get_device(hw->regmap),
61 "failed to read whoami register\n");
62 return err;
63 }
64
65 if (data != ST_UVIS25_REG_WHOAMI_VAL) {
66 dev_err(regmap_get_device(hw->regmap),
67 "wrong whoami {%02x vs %02x}\n",
68 data, ST_UVIS25_REG_WHOAMI_VAL);
69 return -ENODEV;
70 }
71
72 return 0;
73 }
74
st_uvis25_set_enable(struct st_uvis25_hw * hw,bool enable)75 static int st_uvis25_set_enable(struct st_uvis25_hw *hw, bool enable)
76 {
77 int err;
78
79 err = regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL1_ADDR,
80 ST_UVIS25_REG_ODR_MASK, enable);
81 if (err < 0)
82 return err;
83
84 hw->enabled = enable;
85
86 return 0;
87 }
88
st_uvis25_read_oneshot(struct st_uvis25_hw * hw,u8 addr,int * val)89 static int st_uvis25_read_oneshot(struct st_uvis25_hw *hw, u8 addr, int *val)
90 {
91 int err;
92
93 err = st_uvis25_set_enable(hw, true);
94 if (err < 0)
95 return err;
96
97 msleep(1500);
98
99 /*
100 * in order to avoid possible race conditions with interrupt
101 * generation, disable the sensor first and then poll output
102 * register. That sequence guarantees the interrupt will be reset
103 * when irq line is unmasked
104 */
105 err = st_uvis25_set_enable(hw, false);
106 if (err < 0)
107 return err;
108
109 err = regmap_read(hw->regmap, addr, val);
110
111 return err < 0 ? err : IIO_VAL_INT;
112 }
113
st_uvis25_read_raw(struct iio_dev * iio_dev,struct iio_chan_spec const * ch,int * val,int * val2,long mask)114 static int st_uvis25_read_raw(struct iio_dev *iio_dev,
115 struct iio_chan_spec const *ch,
116 int *val, int *val2, long mask)
117 {
118 int ret;
119
120 if (!iio_device_claim_direct(iio_dev))
121 return -EBUSY;
122
123 switch (mask) {
124 case IIO_CHAN_INFO_PROCESSED: {
125 struct st_uvis25_hw *hw = iio_priv(iio_dev);
126
127 /*
128 * mask irq line during oneshot read since the sensor
129 * does not export the capability to disable data-ready line
130 * in the register map and it is enabled by default.
131 * If the line is unmasked during read_raw() it will be set
132 * active and never reset since the trigger is disabled
133 */
134 if (hw->irq > 0)
135 disable_irq(hw->irq);
136 ret = st_uvis25_read_oneshot(hw, ch->address, val);
137 if (hw->irq > 0)
138 enable_irq(hw->irq);
139 break;
140 }
141 default:
142 ret = -EINVAL;
143 break;
144 }
145
146 iio_device_release_direct(iio_dev);
147
148 return ret;
149 }
150
st_uvis25_trigger_handler_thread(int irq,void * private)151 static irqreturn_t st_uvis25_trigger_handler_thread(int irq, void *private)
152 {
153 struct st_uvis25_hw *hw = private;
154 int err, status;
155
156 err = regmap_read(hw->regmap, ST_UVIS25_REG_STATUS_ADDR, &status);
157 if (err < 0)
158 return IRQ_HANDLED;
159
160 if (!(status & ST_UVIS25_REG_UV_DA_MASK))
161 return IRQ_NONE;
162
163 iio_trigger_poll_nested(hw->trig);
164
165 return IRQ_HANDLED;
166 }
167
st_uvis25_allocate_trigger(struct iio_dev * iio_dev)168 static int st_uvis25_allocate_trigger(struct iio_dev *iio_dev)
169 {
170 struct st_uvis25_hw *hw = iio_priv(iio_dev);
171 struct device *dev = regmap_get_device(hw->regmap);
172 bool irq_active_low = false;
173 unsigned long irq_type;
174 int err;
175
176 irq_type = irq_get_trigger_type(hw->irq);
177 switch (irq_type) {
178 case IRQF_TRIGGER_HIGH:
179 case IRQF_TRIGGER_RISING:
180 break;
181 case IRQF_TRIGGER_LOW:
182 case IRQF_TRIGGER_FALLING:
183 irq_active_low = true;
184 break;
185 default:
186 dev_info(dev, "mode %lx unsupported\n", irq_type);
187 return -EINVAL;
188 }
189
190 err = regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL3_ADDR,
191 ST_UVIS25_REG_HL_MASK, irq_active_low);
192 if (err < 0)
193 return err;
194
195 err = devm_request_threaded_irq(dev, hw->irq, NULL,
196 st_uvis25_trigger_handler_thread,
197 irq_type | IRQF_ONESHOT,
198 iio_dev->name, hw);
199 if (err) {
200 dev_err(dev, "failed to request trigger irq %d\n",
201 hw->irq);
202 return err;
203 }
204
205 hw->trig = devm_iio_trigger_alloc(dev, "%s-trigger",
206 iio_dev->name);
207 if (!hw->trig)
208 return -ENOMEM;
209
210 iio_trigger_set_drvdata(hw->trig, iio_dev);
211
212 return devm_iio_trigger_register(dev, hw->trig);
213 }
214
st_uvis25_buffer_preenable(struct iio_dev * iio_dev)215 static int st_uvis25_buffer_preenable(struct iio_dev *iio_dev)
216 {
217 return st_uvis25_set_enable(iio_priv(iio_dev), true);
218 }
219
st_uvis25_buffer_postdisable(struct iio_dev * iio_dev)220 static int st_uvis25_buffer_postdisable(struct iio_dev *iio_dev)
221 {
222 return st_uvis25_set_enable(iio_priv(iio_dev), false);
223 }
224
225 static const struct iio_buffer_setup_ops st_uvis25_buffer_ops = {
226 .preenable = st_uvis25_buffer_preenable,
227 .postdisable = st_uvis25_buffer_postdisable,
228 };
229
st_uvis25_buffer_handler_thread(int irq,void * p)230 static irqreturn_t st_uvis25_buffer_handler_thread(int irq, void *p)
231 {
232 struct iio_poll_func *pf = p;
233 struct iio_dev *iio_dev = pf->indio_dev;
234 struct st_uvis25_hw *hw = iio_priv(iio_dev);
235 unsigned int val;
236 int err;
237
238 err = regmap_read(hw->regmap, ST_UVIS25_REG_OUT_ADDR, &val);
239 if (err < 0)
240 goto out;
241
242 hw->scan.chan = val;
243
244 iio_push_to_buffers_with_timestamp(iio_dev, &hw->scan,
245 iio_get_time_ns(iio_dev));
246
247 out:
248 iio_trigger_notify_done(hw->trig);
249
250 return IRQ_HANDLED;
251 }
252
st_uvis25_allocate_buffer(struct iio_dev * iio_dev)253 static int st_uvis25_allocate_buffer(struct iio_dev *iio_dev)
254 {
255 struct st_uvis25_hw *hw = iio_priv(iio_dev);
256
257 return devm_iio_triggered_buffer_setup(regmap_get_device(hw->regmap),
258 iio_dev, NULL,
259 st_uvis25_buffer_handler_thread,
260 &st_uvis25_buffer_ops);
261 }
262
263 static const struct iio_info st_uvis25_info = {
264 .read_raw = st_uvis25_read_raw,
265 };
266
st_uvis25_init_sensor(struct st_uvis25_hw * hw)267 static int st_uvis25_init_sensor(struct st_uvis25_hw *hw)
268 {
269 int err;
270
271 err = regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL2_ADDR,
272 ST_UVIS25_REG_BOOT_MASK, 1);
273 if (err < 0)
274 return err;
275
276 msleep(2000);
277
278 return regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL1_ADDR,
279 ST_UVIS25_REG_BDU_MASK, 1);
280 }
281
st_uvis25_probe(struct device * dev,int irq,struct regmap * regmap)282 int st_uvis25_probe(struct device *dev, int irq, struct regmap *regmap)
283 {
284 struct st_uvis25_hw *hw;
285 struct iio_dev *iio_dev;
286 int err;
287
288 iio_dev = devm_iio_device_alloc(dev, sizeof(*hw));
289 if (!iio_dev)
290 return -ENOMEM;
291
292 dev_set_drvdata(dev, iio_dev);
293
294 hw = iio_priv(iio_dev);
295 hw->irq = irq;
296 hw->regmap = regmap;
297
298 err = st_uvis25_check_whoami(hw);
299 if (err < 0)
300 return err;
301
302 iio_dev->modes = INDIO_DIRECT_MODE;
303 iio_dev->channels = st_uvis25_channels;
304 iio_dev->num_channels = ARRAY_SIZE(st_uvis25_channels);
305 iio_dev->name = ST_UVIS25_DEV_NAME;
306 iio_dev->info = &st_uvis25_info;
307
308 err = st_uvis25_init_sensor(hw);
309 if (err < 0)
310 return err;
311
312 if (hw->irq > 0) {
313 err = st_uvis25_allocate_buffer(iio_dev);
314 if (err < 0)
315 return err;
316
317 err = st_uvis25_allocate_trigger(iio_dev);
318 if (err)
319 return err;
320 }
321
322 return devm_iio_device_register(dev, iio_dev);
323 }
324 EXPORT_SYMBOL_NS(st_uvis25_probe, "IIO_UVIS25");
325
st_uvis25_suspend(struct device * dev)326 static int st_uvis25_suspend(struct device *dev)
327 {
328 struct iio_dev *iio_dev = dev_get_drvdata(dev);
329 struct st_uvis25_hw *hw = iio_priv(iio_dev);
330
331 return regmap_clear_bits(hw->regmap, ST_UVIS25_REG_CTRL1_ADDR,
332 ST_UVIS25_REG_ODR_MASK);
333 }
334
st_uvis25_resume(struct device * dev)335 static int st_uvis25_resume(struct device *dev)
336 {
337 struct iio_dev *iio_dev = dev_get_drvdata(dev);
338 struct st_uvis25_hw *hw = iio_priv(iio_dev);
339
340 if (hw->enabled)
341 return regmap_update_bits(hw->regmap, ST_UVIS25_REG_CTRL1_ADDR,
342 ST_UVIS25_REG_ODR_MASK, 1);
343
344 return 0;
345 }
346
347 EXPORT_NS_SIMPLE_DEV_PM_OPS(st_uvis25_pm_ops, st_uvis25_suspend, st_uvis25_resume, IIO_UVIS25);
348
349 MODULE_AUTHOR("Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>");
350 MODULE_DESCRIPTION("STMicroelectronics uvis25 sensor driver");
351 MODULE_LICENSE("GPL v2");
352