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) requires 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] ____cacheline_aligned; 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, 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; 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; 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(&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 } 226 227 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(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