1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * TI tlc4541 ADC Driver |
4 | * |
5 | * Copyright (C) 2017 Phil Reid |
6 | * |
7 | * Datasheets can be found here: |
8 | * https://www.ti.com/lit/gpn/tlc3541 |
9 | * https://www.ti.com/lit/gpn/tlc4541 |
10 | * |
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> |
27 | #include <linux/mod_devicetable.h> |
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 | /* |
40 | * DMA (thus cache coherency maintenance) may require the |
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 | */ |
45 | __be16 rx_buf[8] __aligned(IIO_DMA_MINALIGN); |
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(spi: st->spi, message: &st->scan_single_msg); |
99 | if (ret < 0) |
100 | goto done; |
101 | |
102 | iio_push_to_buffers_with_timestamp(indio_dev, data: st->rx_buf, |
103 | timestamp: iio_get_time_ns(indio_dev)); |
104 | |
105 | done: |
106 | iio_trigger_notify_done(trig: 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(regulator: 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(spi: st->spi, message: &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, |
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(parent: &spi->dev, sizeof_priv: sizeof(*st)); |
169 | if (indio_dev == NULL) |
170 | return -ENOMEM; |
171 | |
172 | st = iio_priv(indio_dev); |
173 | |
174 | spi_set_drvdata(spi, data: indio_dev); |
175 | |
176 | st->spi = spi; |
177 | |
178 | info = &tlc4541_chip_info[spi_get_device_id(sdev: spi)->driver_data]; |
179 | |
180 | indio_dev->name = spi_get_device_id(sdev: spi)->name; |
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, buf: &device_init, len: 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; |
192 | st->scan_single_xfer[1].delay.value = 3; |
193 | st->scan_single_xfer[1].delay.unit = SPI_DELAY_UNIT_NSECS; |
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(m: &st->scan_single_msg, |
198 | xfers: st->scan_single_xfer, num_xfers: 3); |
199 | |
200 | st->reg = devm_regulator_get(dev: &spi->dev, id: "vref" ); |
201 | if (IS_ERR(ptr: st->reg)) |
202 | return PTR_ERR(ptr: st->reg); |
203 | |
204 | ret = regulator_enable(regulator: 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(regulator: st->reg); |
223 | |
224 | return ret; |
225 | } |
226 | |
227 | static void tlc4541_remove(struct spi_device *spi) |
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(regulator: st->reg); |
235 | } |
236 | |
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); |
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" , |
254 | .of_match_table = tlc4541_dt_ids, |
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" ); |
265 | |