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(st->spi, &st->scan_single_msg); 99 if (ret < 0) 100 goto done; 101 102 iio_push_to_buffers_with_ts(indio_dev, st->rx_buf, sizeof(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 if (!iio_device_claim_direct(indio_dev)) 135 return -EBUSY; 136 ret = spi_sync(st->spi, &st->scan_single_msg); 137 iio_device_release_direct(indio_dev); 138 if (ret < 0) 139 return ret; 140 *val = be16_to_cpu(st->rx_buf[0]); 141 *val = *val >> chan->scan_type.shift; 142 *val &= GENMASK(chan->scan_type.realbits - 1, 0); 143 return IIO_VAL_INT; 144 case IIO_CHAN_INFO_SCALE: 145 ret = tlc4541_get_range(st); 146 if (ret < 0) 147 return ret; 148 *val = ret; 149 *val2 = chan->scan_type.realbits; 150 return IIO_VAL_FRACTIONAL_LOG2; 151 } 152 return -EINVAL; 153 } 154 155 static const struct iio_info tlc4541_info = { 156 .read_raw = &tlc4541_read_raw, 157 }; 158 159 static int tlc4541_probe(struct spi_device *spi) 160 { 161 struct tlc4541_state *st; 162 struct iio_dev *indio_dev; 163 const struct tlc4541_chip_info *info; 164 int ret; 165 int8_t device_init = 0; 166 167 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); 168 if (indio_dev == NULL) 169 return -ENOMEM; 170 171 st = iio_priv(indio_dev); 172 173 spi_set_drvdata(spi, indio_dev); 174 175 st->spi = spi; 176 177 info = &tlc4541_chip_info[spi_get_device_id(spi)->driver_data]; 178 179 indio_dev->name = spi_get_device_id(spi)->name; 180 indio_dev->modes = INDIO_DIRECT_MODE; 181 indio_dev->channels = info->channels; 182 indio_dev->num_channels = info->num_channels; 183 indio_dev->info = &tlc4541_info; 184 185 /* perform reset */ 186 spi_write(spi, &device_init, 1); 187 188 /* Setup default message */ 189 st->scan_single_xfer[0].rx_buf = &st->rx_buf[0]; 190 st->scan_single_xfer[0].len = 3; 191 st->scan_single_xfer[1].delay.value = 3; 192 st->scan_single_xfer[1].delay.unit = SPI_DELAY_UNIT_NSECS; 193 st->scan_single_xfer[2].rx_buf = &st->rx_buf[0]; 194 st->scan_single_xfer[2].len = 2; 195 196 spi_message_init_with_transfers(&st->scan_single_msg, 197 st->scan_single_xfer, 3); 198 199 st->reg = devm_regulator_get(&spi->dev, "vref"); 200 if (IS_ERR(st->reg)) 201 return PTR_ERR(st->reg); 202 203 ret = regulator_enable(st->reg); 204 if (ret) 205 return ret; 206 207 ret = iio_triggered_buffer_setup(indio_dev, NULL, 208 &tlc4541_trigger_handler, NULL); 209 if (ret) 210 goto error_disable_reg; 211 212 ret = iio_device_register(indio_dev); 213 if (ret) 214 goto error_cleanup_buffer; 215 216 return 0; 217 218 error_cleanup_buffer: 219 iio_triggered_buffer_cleanup(indio_dev); 220 error_disable_reg: 221 regulator_disable(st->reg); 222 223 return ret; 224 } 225 226 static void tlc4541_remove(struct spi_device *spi) 227 { 228 struct iio_dev *indio_dev = spi_get_drvdata(spi); 229 struct tlc4541_state *st = iio_priv(indio_dev); 230 231 iio_device_unregister(indio_dev); 232 iio_triggered_buffer_cleanup(indio_dev); 233 regulator_disable(st->reg); 234 } 235 236 static const struct of_device_id tlc4541_dt_ids[] = { 237 { .compatible = "ti,tlc3541", }, 238 { .compatible = "ti,tlc4541", }, 239 { } 240 }; 241 MODULE_DEVICE_TABLE(of, tlc4541_dt_ids); 242 243 static const struct spi_device_id tlc4541_id[] = { 244 { "tlc3541", TLC3541 }, 245 { "tlc4541", TLC4541 }, 246 { } 247 }; 248 MODULE_DEVICE_TABLE(spi, tlc4541_id); 249 250 static struct spi_driver tlc4541_driver = { 251 .driver = { 252 .name = "tlc4541", 253 .of_match_table = tlc4541_dt_ids, 254 }, 255 .probe = tlc4541_probe, 256 .remove = tlc4541_remove, 257 .id_table = tlc4541_id, 258 }; 259 module_spi_driver(tlc4541_driver); 260 261 MODULE_AUTHOR("Phil Reid <preid@electromag.com.au>"); 262 MODULE_DESCRIPTION("Texas Instruments TLC4541 ADC"); 263 MODULE_LICENSE("GPL v2"); 264