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 int 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 	switch (chan->channel) {
96 	case 0:
97 		return XADC_ALARM_VCCINT_MASK;
98 	case 1:
99 		return XADC_ALARM_VCCAUX_MASK;
100 	case 2:
101 		return XADC_ALARM_VCCBRAM_MASK;
102 	case 3:
103 		return XADC_ALARM_VCCPINT_MASK;
104 	case 4:
105 		return XADC_ALARM_VCCPAUX_MASK;
106 	case 5:
107 		return XADC_ALARM_VCCODDR_MASK;
108 	default:
109 		/* We will never get here */
110 		return 0;
111 	}
112 }
113 
114 int xadc_read_event_config(struct iio_dev *indio_dev,
115 	const struct iio_chan_spec *chan, enum iio_event_type type,
116 	enum iio_event_direction dir)
117 {
118 	struct xadc *xadc = iio_priv(indio_dev);
119 
120 	return (bool)(xadc->alarm_mask & xadc_get_alarm_mask(chan));
121 }
122 
123 int xadc_write_event_config(struct iio_dev *indio_dev,
124 	const struct iio_chan_spec *chan, enum iio_event_type type,
125 	enum iio_event_direction dir, int state)
126 {
127 	unsigned int alarm = xadc_get_alarm_mask(chan);
128 	struct xadc *xadc = iio_priv(indio_dev);
129 	uint16_t cfg, old_cfg;
130 	int ret;
131 
132 	mutex_lock(&xadc->mutex);
133 
134 	if (state)
135 		xadc->alarm_mask |= alarm;
136 	else
137 		xadc->alarm_mask &= ~alarm;
138 
139 	xadc->ops->update_alarm(xadc, xadc->alarm_mask);
140 
141 	ret = _xadc_read_adc_reg(xadc, XADC_REG_CONF1, &cfg);
142 	if (ret)
143 		goto err_out;
144 
145 	old_cfg = cfg;
146 	cfg |= XADC_CONF1_ALARM_MASK;
147 	cfg &= ~((xadc->alarm_mask & 0xf0) << 4); /* bram, pint, paux, ddr */
148 	cfg &= ~((xadc->alarm_mask & 0x08) >> 3); /* ot */
149 	cfg &= ~((xadc->alarm_mask & 0x07) << 1); /* temp, vccint, vccaux */
150 	if (old_cfg != cfg)
151 		ret = _xadc_write_adc_reg(xadc, XADC_REG_CONF1, cfg);
152 
153 err_out:
154 	mutex_unlock(&xadc->mutex);
155 
156 	return ret;
157 }
158 
159 /* Register value is msb aligned, the lower 4 bits are ignored */
160 #define XADC_THRESHOLD_VALUE_SHIFT 4
161 
162 int xadc_read_event_value(struct iio_dev *indio_dev,
163 	const struct iio_chan_spec *chan, enum iio_event_type type,
164 	enum iio_event_direction dir, enum iio_event_info info,
165 	int *val, int *val2)
166 {
167 	unsigned int offset = xadc_get_threshold_offset(chan, dir);
168 	struct xadc *xadc = iio_priv(indio_dev);
169 
170 	switch (info) {
171 	case IIO_EV_INFO_VALUE:
172 		*val = xadc->threshold[offset];
173 		break;
174 	case IIO_EV_INFO_HYSTERESIS:
175 		*val = xadc->temp_hysteresis;
176 		break;
177 	default:
178 		return -EINVAL;
179 	}
180 
181 	*val >>= XADC_THRESHOLD_VALUE_SHIFT;
182 
183 	return IIO_VAL_INT;
184 }
185 
186 int xadc_write_event_value(struct iio_dev *indio_dev,
187 	const struct iio_chan_spec *chan, enum iio_event_type type,
188 	enum iio_event_direction dir, enum iio_event_info info,
189 	int val, int val2)
190 {
191 	unsigned int offset = xadc_get_threshold_offset(chan, dir);
192 	struct xadc *xadc = iio_priv(indio_dev);
193 	int ret = 0;
194 
195 	val <<= XADC_THRESHOLD_VALUE_SHIFT;
196 
197 	if (val < 0 || val > 0xffff)
198 		return -EINVAL;
199 
200 	mutex_lock(&xadc->mutex);
201 
202 	switch (info) {
203 	case IIO_EV_INFO_VALUE:
204 		xadc->threshold[offset] = val;
205 		break;
206 	case IIO_EV_INFO_HYSTERESIS:
207 		xadc->temp_hysteresis = val;
208 		break;
209 	default:
210 		mutex_unlock(&xadc->mutex);
211 		return -EINVAL;
212 	}
213 
214 	if (chan->type == IIO_TEMP) {
215 		/*
216 		 * According to the datasheet we need to set the lower 4 bits to
217 		 * 0x3, otherwise 125 degree celsius will be used as the
218 		 * threshold.
219 		 */
220 		val |= 0x3;
221 
222 		/*
223 		 * Since we store the hysteresis as relative (to the threshold)
224 		 * value, but the hardware expects an absolute value we need to
225 		 * recalcualte this value whenever the hysteresis or the
226 		 * threshold changes.
227 		 */
228 		if (xadc->threshold[offset] < xadc->temp_hysteresis)
229 			xadc->threshold[offset + 4] = 0;
230 		else
231 			xadc->threshold[offset + 4] = xadc->threshold[offset] -
232 					xadc->temp_hysteresis;
233 		ret = _xadc_write_adc_reg(xadc, XADC_REG_THRESHOLD(offset + 4),
234 			xadc->threshold[offset + 4]);
235 		if (ret)
236 			goto out_unlock;
237 	}
238 
239 	if (info == IIO_EV_INFO_VALUE)
240 		ret = _xadc_write_adc_reg(xadc, XADC_REG_THRESHOLD(offset), val);
241 
242 out_unlock:
243 	mutex_unlock(&xadc->mutex);
244 
245 	return ret;
246 }
247