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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
ac2bec9d PR |
2 | /* |
3 | * TI tlc4541 ADC Driver | |
4 | * | |
5 | * Copyright (C) 2017 Phil Reid | |
6 | * | |
7 | * Datasheets can be found here: | |
3593cd53 AK |
8 | * https://www.ti.com/lit/gpn/tlc3541 |
9 | * https://www.ti.com/lit/gpn/tlc4541 | |
ac2bec9d | 10 | * |
ac2bec9d PR |
11 | * The tlc4541 requires 24 clock cycles to start a transfer. |
12 | * Conversion then takes 2.94us to complete before data is ready | |
13 | * Data is returned MSB first. | |
14 | */ | |
15 | ||
16 | #include <linux/delay.h> | |
17 | #include <linux/device.h> | |
18 | #include <linux/err.h> | |
19 | #include <linux/interrupt.h> | |
20 | #include <linux/iio/iio.h> | |
21 | #include <linux/iio/sysfs.h> | |
22 | #include <linux/iio/buffer.h> | |
23 | #include <linux/iio/trigger_consumer.h> | |
24 | #include <linux/iio/triggered_buffer.h> | |
25 | #include <linux/kernel.h> | |
26 | #include <linux/module.h> | |
4e53d47f | 27 | #include <linux/mod_devicetable.h> |
ac2bec9d PR |
28 | #include <linux/regulator/consumer.h> |
29 | #include <linux/slab.h> | |
30 | #include <linux/spi/spi.h> | |
31 | #include <linux/sysfs.h> | |
32 | ||
33 | struct tlc4541_state { | |
34 | struct spi_device *spi; | |
35 | struct regulator *reg; | |
36 | struct spi_transfer scan_single_xfer[3]; | |
37 | struct spi_message scan_single_msg; | |
38 | ||
39 | /* | |
62fa19bf | 40 | * DMA (thus cache coherency maintenance) may require the |
ac2bec9d PR |
41 | * transfer buffers to live in their own cache lines. |
42 | * 2 bytes data + 6 bytes padding + 8 bytes timestamp when | |
43 | * call iio_push_to_buffers_with_timestamp. | |
44 | */ | |
62fa19bf | 45 | __be16 rx_buf[8] __aligned(IIO_DMA_MINALIGN); |
ac2bec9d PR |
46 | }; |
47 | ||
48 | struct tlc4541_chip_info { | |
49 | const struct iio_chan_spec *channels; | |
50 | unsigned int num_channels; | |
51 | }; | |
52 | ||
53 | enum tlc4541_id { | |
54 | TLC3541, | |
55 | TLC4541, | |
56 | }; | |
57 | ||
58 | #define TLC4541_V_CHAN(bits, bitshift) { \ | |
59 | .type = IIO_VOLTAGE, \ | |
60 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ | |
61 | .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ | |
62 | .scan_type = { \ | |
63 | .sign = 'u', \ | |
64 | .realbits = (bits), \ | |
65 | .storagebits = 16, \ | |
66 | .shift = (bitshift), \ | |
67 | .endianness = IIO_BE, \ | |
68 | }, \ | |
69 | } | |
70 | ||
71 | #define DECLARE_TLC4541_CHANNELS(name, bits, bitshift) \ | |
72 | const struct iio_chan_spec name ## _channels[] = { \ | |
73 | TLC4541_V_CHAN(bits, bitshift), \ | |
74 | IIO_CHAN_SOFT_TIMESTAMP(1), \ | |
75 | } | |
76 | ||
77 | static DECLARE_TLC4541_CHANNELS(tlc3541, 14, 2); | |
78 | static DECLARE_TLC4541_CHANNELS(tlc4541, 16, 0); | |
79 | ||
80 | static const struct tlc4541_chip_info tlc4541_chip_info[] = { | |
81 | [TLC3541] = { | |
82 | .channels = tlc3541_channels, | |
83 | .num_channels = ARRAY_SIZE(tlc3541_channels), | |
84 | }, | |
85 | [TLC4541] = { | |
86 | .channels = tlc4541_channels, | |
87 | .num_channels = ARRAY_SIZE(tlc4541_channels), | |
88 | }, | |
89 | }; | |
90 | ||
91 | static irqreturn_t tlc4541_trigger_handler(int irq, void *p) | |
92 | { | |
93 | struct iio_poll_func *pf = p; | |
94 | struct iio_dev *indio_dev = pf->indio_dev; | |
95 | struct tlc4541_state *st = iio_priv(indio_dev); | |
96 | int ret; | |
97 | ||
98 | ret = spi_sync(st->spi, &st->scan_single_msg); | |
99 | if (ret < 0) | |
100 | goto done; | |
101 | ||
102 | iio_push_to_buffers_with_timestamp(indio_dev, st->rx_buf, | |
103 | iio_get_time_ns(indio_dev)); | |
104 | ||
105 | done: | |
106 | iio_trigger_notify_done(indio_dev->trig); | |
107 | return IRQ_HANDLED; | |
108 | } | |
109 | ||
110 | static int tlc4541_get_range(struct tlc4541_state *st) | |
111 | { | |
112 | int vref; | |
113 | ||
114 | vref = regulator_get_voltage(st->reg); | |
115 | if (vref < 0) | |
116 | return vref; | |
117 | ||
118 | vref /= 1000; | |
119 | ||
120 | return vref; | |
121 | } | |
122 | ||
123 | static int tlc4541_read_raw(struct iio_dev *indio_dev, | |
124 | struct iio_chan_spec const *chan, | |
125 | int *val, | |
126 | int *val2, | |
127 | long m) | |
128 | { | |
129 | int ret = 0; | |
130 | struct tlc4541_state *st = iio_priv(indio_dev); | |
131 | ||
132 | switch (m) { | |
133 | case IIO_CHAN_INFO_RAW: | |
134 | ret = iio_device_claim_direct_mode(indio_dev); | |
135 | if (ret) | |
136 | return ret; | |
137 | ret = spi_sync(st->spi, &st->scan_single_msg); | |
138 | iio_device_release_direct_mode(indio_dev); | |
139 | if (ret < 0) | |
140 | return ret; | |
141 | *val = be16_to_cpu(st->rx_buf[0]); | |
142 | *val = *val >> chan->scan_type.shift; | |
143 | *val &= GENMASK(chan->scan_type.realbits - 1, 0); | |
144 | return IIO_VAL_INT; | |
145 | case IIO_CHAN_INFO_SCALE: | |
146 | ret = tlc4541_get_range(st); | |
147 | if (ret < 0) | |
148 | return ret; | |
149 | *val = ret; | |
150 | *val2 = chan->scan_type.realbits; | |
151 | return IIO_VAL_FRACTIONAL_LOG2; | |
152 | } | |
153 | return -EINVAL; | |
154 | } | |
155 | ||
156 | static const struct iio_info tlc4541_info = { | |
157 | .read_raw = &tlc4541_read_raw, | |
ac2bec9d PR |
158 | }; |
159 | ||
160 | static int tlc4541_probe(struct spi_device *spi) | |
161 | { | |
162 | struct tlc4541_state *st; | |
163 | struct iio_dev *indio_dev; | |
164 | const struct tlc4541_chip_info *info; | |
165 | int ret; | |
166 | int8_t device_init = 0; | |
167 | ||
168 | indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); | |
169 | if (indio_dev == NULL) | |
170 | return -ENOMEM; | |
171 | ||
172 | st = iio_priv(indio_dev); | |
173 | ||
174 | spi_set_drvdata(spi, indio_dev); | |
175 | ||
176 | st->spi = spi; | |
177 | ||
178 | info = &tlc4541_chip_info[spi_get_device_id(spi)->driver_data]; | |
179 | ||
180 | indio_dev->name = spi_get_device_id(spi)->name; | |
ac2bec9d PR |
181 | indio_dev->modes = INDIO_DIRECT_MODE; |
182 | indio_dev->channels = info->channels; | |
183 | indio_dev->num_channels = info->num_channels; | |
184 | indio_dev->info = &tlc4541_info; | |
185 | ||
186 | /* perform reset */ | |
187 | spi_write(spi, &device_init, 1); | |
188 | ||
189 | /* Setup default message */ | |
190 | st->scan_single_xfer[0].rx_buf = &st->rx_buf[0]; | |
191 | st->scan_single_xfer[0].len = 3; | |
ccea1f5a SC |
192 | st->scan_single_xfer[1].delay.value = 3; |
193 | st->scan_single_xfer[1].delay.unit = SPI_DELAY_UNIT_NSECS; | |
ac2bec9d PR |
194 | st->scan_single_xfer[2].rx_buf = &st->rx_buf[0]; |
195 | st->scan_single_xfer[2].len = 2; | |
196 | ||
197 | spi_message_init_with_transfers(&st->scan_single_msg, | |
198 | st->scan_single_xfer, 3); | |
199 | ||
200 | st->reg = devm_regulator_get(&spi->dev, "vref"); | |
201 | if (IS_ERR(st->reg)) | |
202 | return PTR_ERR(st->reg); | |
203 | ||
204 | ret = regulator_enable(st->reg); | |
205 | if (ret) | |
206 | return ret; | |
207 | ||
208 | ret = iio_triggered_buffer_setup(indio_dev, NULL, | |
209 | &tlc4541_trigger_handler, NULL); | |
210 | if (ret) | |
211 | goto error_disable_reg; | |
212 | ||
213 | ret = iio_device_register(indio_dev); | |
214 | if (ret) | |
215 | goto error_cleanup_buffer; | |
216 | ||
217 | return 0; | |
218 | ||
219 | error_cleanup_buffer: | |
220 | iio_triggered_buffer_cleanup(indio_dev); | |
221 | error_disable_reg: | |
222 | regulator_disable(st->reg); | |
223 | ||
224 | return ret; | |
225 | } | |
226 | ||
a0386bba | 227 | static void tlc4541_remove(struct spi_device *spi) |
ac2bec9d PR |
228 | { |
229 | struct iio_dev *indio_dev = spi_get_drvdata(spi); | |
230 | struct tlc4541_state *st = iio_priv(indio_dev); | |
231 | ||
232 | iio_device_unregister(indio_dev); | |
233 | iio_triggered_buffer_cleanup(indio_dev); | |
234 | regulator_disable(st->reg); | |
ac2bec9d PR |
235 | } |
236 | ||
ac2bec9d PR |
237 | static const struct of_device_id tlc4541_dt_ids[] = { |
238 | { .compatible = "ti,tlc3541", }, | |
239 | { .compatible = "ti,tlc4541", }, | |
240 | {} | |
241 | }; | |
242 | MODULE_DEVICE_TABLE(of, tlc4541_dt_ids); | |
ac2bec9d PR |
243 | |
244 | static const struct spi_device_id tlc4541_id[] = { | |
245 | {"tlc3541", TLC3541}, | |
246 | {"tlc4541", TLC4541}, | |
247 | {} | |
248 | }; | |
249 | MODULE_DEVICE_TABLE(spi, tlc4541_id); | |
250 | ||
251 | static struct spi_driver tlc4541_driver = { | |
252 | .driver = { | |
253 | .name = "tlc4541", | |
4e53d47f | 254 | .of_match_table = tlc4541_dt_ids, |
ac2bec9d PR |
255 | }, |
256 | .probe = tlc4541_probe, | |
257 | .remove = tlc4541_remove, | |
258 | .id_table = tlc4541_id, | |
259 | }; | |
260 | module_spi_driver(tlc4541_driver); | |
261 | ||
262 | MODULE_AUTHOR("Phil Reid <preid@electromag.com.au>"); | |
263 | MODULE_DESCRIPTION("Texas Instruments TLC4541 ADC"); | |
264 | MODULE_LICENSE("GPL v2"); |