1 /*
2  * Xilinx XADC driver
3  *
4  * Copyright 2013 Analog Devices Inc.
5  *  Author: Lars-Peter Clauen <lars@metafoo.de>
6  *
7  * Licensed under the GPL-2.
8  */
9 
10 #include <linux/iio/events.h>
11 #include <linux/iio/iio.h>
12 #include <linux/kernel.h>
13 
14 #include "xilinx-xadc.h"
15 
16 static const struct iio_chan_spec *xadc_event_to_channel(
17 	struct iio_dev *indio_dev, unsigned int event)
18 {
19 	switch (event) {
20 	case XADC_THRESHOLD_OT_MAX:
21 	case XADC_THRESHOLD_TEMP_MAX:
22 		return &indio_dev->channels[0];
23 	case XADC_THRESHOLD_VCCINT_MAX:
24 	case XADC_THRESHOLD_VCCAUX_MAX:
25 		return &indio_dev->channels[event];
26 	default:
27 		return &indio_dev->channels[event-1];
28 	}
29 }
30 
31 static void xadc_handle_event(struct iio_dev *indio_dev, unsigned int event)
32 {
33 	const struct iio_chan_spec *chan;
34 
35 	/* Temperature threshold error, we don't handle this yet */
36 	if (event == 0)
37 		return;
38 
39 	chan = xadc_event_to_channel(indio_dev, event);
40 
41 	if (chan->type == IIO_TEMP) {
42 		/*
43 		 * The temperature channel only supports over-temperature
44 		 * events.
45 		 */
46 		iio_push_event(indio_dev,
47 			IIO_UNMOD_EVENT_CODE(chan->type, chan->channel,
48 				IIO_EV_TYPE_THRESH, IIO_EV_DIR_RISING),
49 			iio_get_time_ns(indio_dev));
50 	} else {
51 		/*
52 		 * For other channels we don't know whether it is a upper or
53 		 * lower threshold event. Userspace will have to check the
54 		 * channel value if it wants to know.
55 		 */
56 		iio_push_event(indio_dev,
57 			IIO_UNMOD_EVENT_CODE(chan->type, chan->channel,
58 				IIO_EV_TYPE_THRESH, IIO_EV_DIR_EITHER),
59 			iio_get_time_ns(indio_dev));
60 	}
61 }
62 
63 void xadc_handle_events(struct iio_dev *indio_dev, unsigned long events)
64 {
65 	unsigned int i;
66 
67 	for_each_set_bit(i, &events, 8)
68 		xadc_handle_event(indio_dev, i);
69 }
70 
71 static unsigned xadc_get_threshold_offset(const struct iio_chan_spec *chan,
72 	enum iio_event_direction dir)
73 {
74 	unsigned int offset;
75 
76 	if (chan->type == IIO_TEMP) {
77 		offset = XADC_THRESHOLD_OT_MAX;
78 	} else {
79 		if (chan->channel < 2)
80 			offset = chan->channel + 1;
81 		else
82 			offset = chan->channel + 6;
83 	}
84 
85 	if (dir == IIO_EV_DIR_FALLING)
86 		offset += 4;
87 
88 	return offset;
89 }
90 
91 static unsigned int xadc_get_alarm_mask(const struct iio_chan_spec *chan)
92 {
93 	if (chan->type == IIO_TEMP) {
94 		return XADC_ALARM_OT_MASK;
95 	} else {
96 		switch (chan->channel) {
97 		case 0:
98 			return XADC_ALARM_VCCINT_MASK;
99 		case 1:
100 			return XADC_ALARM_VCCAUX_MASK;
101 		case 2:
102 			return XADC_ALARM_VCCBRAM_MASK;
103 		case 3:
104 			return XADC_ALARM_VCCPINT_MASK;
105 		case 4:
106 			return XADC_ALARM_VCCPAUX_MASK;
107 		case 5:
108 			return XADC_ALARM_VCCODDR_MASK;
109 		default:
110 			/* We will never get here */
111 			return 0;
112 		}
113 	}
114 }
115 
116 int xadc_read_event_config(struct iio_dev *indio_dev,
117 	const struct iio_chan_spec *chan, enum iio_event_type type,
118 	enum iio_event_direction dir)
119 {
120 	struct xadc *xadc = iio_priv(indio_dev);
121 
122 	return (bool)(xadc->alarm_mask & xadc_get_alarm_mask(chan));
123 }
124 
125 int xadc_write_event_config(struct iio_dev *indio_dev,
126 	const struct iio_chan_spec *chan, enum iio_event_type type,
127 	enum iio_event_direction dir, int state)
128 {
129 	unsigned int alarm = xadc_get_alarm_mask(chan);
130 	struct xadc *xadc = iio_priv(indio_dev);
131 	uint16_t cfg, old_cfg;
132 	int ret;
133 
134 	mutex_lock(&xadc->mutex);
135 
136 	if (state)
137 		xadc->alarm_mask |= alarm;
138 	else
139 		xadc->alarm_mask &= ~alarm;
140 
141 	xadc->ops->update_alarm(xadc, xadc->alarm_mask);
142 
143 	ret = _xadc_read_adc_reg(xadc, XADC_REG_CONF1, &cfg);
144 	if (ret)
145 		goto err_out;
146 
147 	old_cfg = cfg;
148 	cfg |= XADC_CONF1_ALARM_MASK;
149 	cfg &= ~((xadc->alarm_mask & 0xf0) << 4); /* bram, pint, paux, ddr */
150 	cfg &= ~((xadc->alarm_mask & 0x08) >> 3); /* ot */
151 	cfg &= ~((xadc->alarm_mask & 0x07) << 1); /* temp, vccint, vccaux */
152 	if (old_cfg != cfg)
153 		ret = _xadc_write_adc_reg(xadc, XADC_REG_CONF1, cfg);
154 
155 err_out:
156 	mutex_unlock(&xadc->mutex);
157 
158 	return ret;
159 }
160 
161 /* Register value is msb aligned, the lower 4 bits are ignored */
162 #define XADC_THRESHOLD_VALUE_SHIFT 4
163 
164 int xadc_read_event_value(struct iio_dev *indio_dev,
165 	const struct iio_chan_spec *chan, enum iio_event_type type,
166 	enum iio_event_direction dir, enum iio_event_info info,
167 	int *val, int *val2)
168 {
169 	unsigned int offset = xadc_get_threshold_offset(chan, dir);
170 	struct xadc *xadc = iio_priv(indio_dev);
171 
172 	switch (info) {
173 	case IIO_EV_INFO_VALUE:
174 		*val = xadc->threshold[offset];
175 		break;
176 	case IIO_EV_INFO_HYSTERESIS:
177 		*val = xadc->temp_hysteresis;
178 		break;
179 	default:
180 		return -EINVAL;
181 	}
182 
183 	*val >>= XADC_THRESHOLD_VALUE_SHIFT;
184 
185 	return IIO_VAL_INT;
186 }
187 
188 int xadc_write_event_value(struct iio_dev *indio_dev,
189 	const struct iio_chan_spec *chan, enum iio_event_type type,
190 	enum iio_event_direction dir, enum iio_event_info info,
191 	int val, int val2)
192 {
193 	unsigned int offset = xadc_get_threshold_offset(chan, dir);
194 	struct xadc *xadc = iio_priv(indio_dev);
195 	int ret = 0;
196 
197 	val <<= XADC_THRESHOLD_VALUE_SHIFT;
198 
199 	if (val < 0 || val > 0xffff)
200 		return -EINVAL;
201 
202 	mutex_lock(&xadc->mutex);
203 
204 	switch (info) {
205 	case IIO_EV_INFO_VALUE:
206 		xadc->threshold[offset] = val;
207 		break;
208 	case IIO_EV_INFO_HYSTERESIS:
209 		xadc->temp_hysteresis = val;
210 		break;
211 	default:
212 		mutex_unlock(&xadc->mutex);
213 		return -EINVAL;
214 	}
215 
216 	if (chan->type == IIO_TEMP) {
217 		/*
218 		 * According to the datasheet we need to set the lower 4 bits to
219 		 * 0x3, otherwise 125 degree celsius will be used as the
220 		 * threshold.
221 		 */
222 		val |= 0x3;
223 
224 		/*
225 		 * Since we store the hysteresis as relative (to the threshold)
226 		 * value, but the hardware expects an absolute value we need to
227 		 * recalcualte this value whenever the hysteresis or the
228 		 * threshold changes.
229 		 */
230 		if (xadc->threshold[offset] < xadc->temp_hysteresis)
231 			xadc->threshold[offset + 4] = 0;
232 		else
233 			xadc->threshold[offset + 4] = xadc->threshold[offset] -
234 					xadc->temp_hysteresis;
235 		ret = _xadc_write_adc_reg(xadc, XADC_REG_THRESHOLD(offset + 4),
236 			xadc->threshold[offset + 4]);
237 		if (ret)
238 			goto out_unlock;
239 	}
240 
241 	if (info == IIO_EV_INFO_VALUE)
242 		ret = _xadc_write_adc_reg(xadc, XADC_REG_THRESHOLD(offset), val);
243 
244 out_unlock:
245 	mutex_unlock(&xadc->mutex);
246 
247 	return ret;
248 }
249