Matt Ranostay | 4d671b7 | 2016-08-19 20:17:03 -0700 | [diff] [blame] | 1 | /* |
| 2 | * ti-adc161s626.c - Texas Instruments ADC161S626 1-channel differential ADC |
| 3 | * |
| 4 | * ADC Devices Supported: |
| 5 | * adc141s626 - 14-bit ADC |
| 6 | * adc161s626 - 16-bit ADC |
| 7 | * |
| 8 | * Copyright (C) 2016 Matt Ranostay <mranostay@gmail.com> |
| 9 | * |
| 10 | * This program is free software; you can redistribute it and/or modify |
| 11 | * it under the terms of the GNU General Public License as published by |
| 12 | * the Free Software Foundation; either version 2 of the License, or |
| 13 | * (at your option) any later version. |
| 14 | * |
| 15 | * This program is distributed in the hope that it will be useful, |
| 16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 18 | * GNU General Public License for more details. |
| 19 | */ |
| 20 | |
| 21 | #include <linux/module.h> |
| 22 | #include <linux/init.h> |
| 23 | #include <linux/err.h> |
| 24 | #include <linux/spi/spi.h> |
| 25 | #include <linux/iio/iio.h> |
| 26 | #include <linux/iio/trigger.h> |
| 27 | #include <linux/iio/buffer.h> |
| 28 | #include <linux/iio/trigger_consumer.h> |
| 29 | #include <linux/iio/triggered_buffer.h> |
| 30 | |
| 31 | #define TI_ADC_DRV_NAME "ti-adc161s626" |
| 32 | |
| 33 | enum { |
| 34 | TI_ADC141S626, |
| 35 | TI_ADC161S626, |
| 36 | }; |
| 37 | |
| 38 | static const struct iio_chan_spec ti_adc141s626_channels[] = { |
| 39 | { |
| 40 | .type = IIO_VOLTAGE, |
| 41 | .channel = 0, |
| 42 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), |
| 43 | .scan_index = 0, |
| 44 | .scan_type = { |
| 45 | .sign = 's', |
| 46 | .realbits = 14, |
| 47 | .storagebits = 16, |
| 48 | }, |
| 49 | }, |
| 50 | IIO_CHAN_SOFT_TIMESTAMP(1), |
| 51 | }; |
| 52 | |
| 53 | static const struct iio_chan_spec ti_adc161s626_channels[] = { |
| 54 | { |
| 55 | .type = IIO_VOLTAGE, |
| 56 | .channel = 0, |
| 57 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), |
| 58 | .scan_index = 0, |
| 59 | .scan_type = { |
| 60 | .sign = 's', |
| 61 | .realbits = 16, |
| 62 | .storagebits = 16, |
| 63 | }, |
| 64 | }, |
| 65 | IIO_CHAN_SOFT_TIMESTAMP(1), |
| 66 | }; |
| 67 | |
| 68 | struct ti_adc_data { |
| 69 | struct iio_dev *indio_dev; |
| 70 | struct spi_device *spi; |
| 71 | u8 read_size; |
| 72 | u8 shift; |
| 73 | |
| 74 | u8 buffer[16] ____cacheline_aligned; |
| 75 | }; |
| 76 | |
| 77 | static int ti_adc_read_measurement(struct ti_adc_data *data, |
| 78 | struct iio_chan_spec const *chan, int *val) |
| 79 | { |
| 80 | int ret; |
| 81 | |
| 82 | switch (data->read_size) { |
| 83 | case 2: { |
| 84 | __be16 buf; |
| 85 | |
| 86 | ret = spi_read(data->spi, (void *) &buf, 2); |
| 87 | if (ret) |
| 88 | return ret; |
| 89 | |
| 90 | *val = be16_to_cpu(buf); |
| 91 | break; |
| 92 | } |
| 93 | case 3: { |
| 94 | __be32 buf; |
| 95 | |
| 96 | ret = spi_read(data->spi, (void *) &buf, 3); |
| 97 | if (ret) |
| 98 | return ret; |
| 99 | |
| 100 | *val = be32_to_cpu(buf) >> 8; |
| 101 | break; |
| 102 | } |
| 103 | default: |
| 104 | return -EINVAL; |
| 105 | } |
| 106 | |
| 107 | *val = sign_extend32(*val >> data->shift, chan->scan_type.realbits - 1); |
| 108 | |
| 109 | return 0; |
| 110 | } |
| 111 | |
| 112 | static irqreturn_t ti_adc_trigger_handler(int irq, void *private) |
| 113 | { |
| 114 | struct iio_poll_func *pf = private; |
| 115 | struct iio_dev *indio_dev = pf->indio_dev; |
| 116 | struct ti_adc_data *data = iio_priv(indio_dev); |
| 117 | int ret; |
| 118 | |
| 119 | ret = ti_adc_read_measurement(data, &indio_dev->channels[0], |
| 120 | (int *) &data->buffer); |
| 121 | if (!ret) |
| 122 | iio_push_to_buffers_with_timestamp(indio_dev, |
| 123 | data->buffer, |
| 124 | iio_get_time_ns(indio_dev)); |
| 125 | |
| 126 | iio_trigger_notify_done(indio_dev->trig); |
| 127 | |
| 128 | return IRQ_HANDLED; |
| 129 | } |
| 130 | |
| 131 | static int ti_adc_read_raw(struct iio_dev *indio_dev, |
| 132 | struct iio_chan_spec const *chan, |
| 133 | int *val, int *val2, long mask) |
| 134 | { |
| 135 | struct ti_adc_data *data = iio_priv(indio_dev); |
| 136 | int ret; |
| 137 | |
| 138 | if (mask != IIO_CHAN_INFO_RAW) |
| 139 | return -EINVAL; |
| 140 | |
| 141 | ret = iio_device_claim_direct_mode(indio_dev); |
| 142 | if (ret) |
| 143 | return ret; |
| 144 | |
| 145 | ret = ti_adc_read_measurement(data, chan, val); |
| 146 | iio_device_release_direct_mode(indio_dev); |
| 147 | |
| 148 | if (!ret) |
| 149 | return IIO_VAL_INT; |
| 150 | |
| 151 | return 0; |
| 152 | } |
| 153 | |
| 154 | static const struct iio_info ti_adc_info = { |
| 155 | .driver_module = THIS_MODULE, |
| 156 | .read_raw = ti_adc_read_raw, |
| 157 | }; |
| 158 | |
| 159 | static int ti_adc_probe(struct spi_device *spi) |
| 160 | { |
| 161 | struct iio_dev *indio_dev; |
| 162 | struct ti_adc_data *data; |
| 163 | int ret; |
| 164 | |
| 165 | indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*data)); |
| 166 | if (!indio_dev) |
| 167 | return -ENOMEM; |
| 168 | |
| 169 | indio_dev->info = &ti_adc_info; |
| 170 | indio_dev->dev.parent = &spi->dev; |
| 171 | indio_dev->dev.of_node = spi->dev.of_node; |
| 172 | indio_dev->name = TI_ADC_DRV_NAME; |
| 173 | indio_dev->modes = INDIO_DIRECT_MODE; |
| 174 | spi_set_drvdata(spi, indio_dev); |
| 175 | |
| 176 | data = iio_priv(indio_dev); |
| 177 | data->spi = spi; |
| 178 | |
| 179 | switch (spi_get_device_id(spi)->driver_data) { |
| 180 | case TI_ADC141S626: |
| 181 | indio_dev->channels = ti_adc141s626_channels; |
| 182 | indio_dev->num_channels = ARRAY_SIZE(ti_adc141s626_channels); |
| 183 | data->shift = 0; |
| 184 | data->read_size = 2; |
| 185 | break; |
| 186 | case TI_ADC161S626: |
| 187 | indio_dev->channels = ti_adc161s626_channels; |
| 188 | indio_dev->num_channels = ARRAY_SIZE(ti_adc161s626_channels); |
| 189 | data->shift = 6; |
| 190 | data->read_size = 3; |
| 191 | break; |
| 192 | } |
| 193 | |
| 194 | ret = iio_triggered_buffer_setup(indio_dev, NULL, |
| 195 | ti_adc_trigger_handler, NULL); |
| 196 | if (ret) |
| 197 | return ret; |
| 198 | |
| 199 | ret = iio_device_register(indio_dev); |
| 200 | if (ret) |
| 201 | goto error_unreg_buffer; |
| 202 | |
| 203 | return 0; |
| 204 | |
| 205 | error_unreg_buffer: |
| 206 | iio_triggered_buffer_cleanup(indio_dev); |
| 207 | |
| 208 | return ret; |
| 209 | } |
| 210 | |
| 211 | static int ti_adc_remove(struct spi_device *spi) |
| 212 | { |
| 213 | struct iio_dev *indio_dev = spi_get_drvdata(spi); |
| 214 | |
| 215 | iio_device_unregister(indio_dev); |
| 216 | iio_triggered_buffer_cleanup(indio_dev); |
| 217 | |
| 218 | return 0; |
| 219 | } |
| 220 | |
| 221 | static const struct of_device_id ti_adc_dt_ids[] = { |
| 222 | { .compatible = "ti,adc141s626", }, |
| 223 | { .compatible = "ti,adc161s626", }, |
| 224 | {} |
| 225 | }; |
| 226 | MODULE_DEVICE_TABLE(of, ti_adc_dt_ids); |
| 227 | |
| 228 | static const struct spi_device_id ti_adc_id[] = { |
| 229 | {"adc141s626", TI_ADC141S626}, |
| 230 | {"adc161s626", TI_ADC161S626}, |
| 231 | {}, |
| 232 | }; |
| 233 | MODULE_DEVICE_TABLE(spi, ti_adc_id); |
| 234 | |
| 235 | static struct spi_driver ti_adc_driver = { |
| 236 | .driver = { |
| 237 | .name = TI_ADC_DRV_NAME, |
| 238 | .of_match_table = of_match_ptr(ti_adc_dt_ids), |
| 239 | }, |
| 240 | .probe = ti_adc_probe, |
| 241 | .remove = ti_adc_remove, |
| 242 | .id_table = ti_adc_id, |
| 243 | }; |
| 244 | module_spi_driver(ti_adc_driver); |
| 245 | |
| 246 | MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>"); |
| 247 | MODULE_DESCRIPTION("Texas Instruments ADC1x1S 1-channel differential ADC"); |
| 248 | MODULE_LICENSE("GPL"); |