1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * ltc2496.c - Driver for Analog Devices/Linear Technology LTC2496 ADC 4 * 5 * Based on ltc2497.c which has 6 * Copyright (C) 2017 Analog Devices Inc. 7 * 8 * Licensed under the GPL-2. 9 * 10 * Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/2496fc.pdf 11 */ 12 13 #include <linux/spi/spi.h> 14 #include <linux/iio/iio.h> 15 #include <linux/iio/driver.h> 16 #include <linux/module.h> 17 #include <linux/mod_devicetable.h> 18 #include <linux/property.h> 19 20 #include "ltc2497.h" 21 22 struct ltc2496_driverdata { 23 /* this must be the first member */ 24 struct ltc2497core_driverdata common_ddata; 25 struct spi_device *spi; 26 27 /* 28 * DMA (thus cache coherency maintenance) may require the 29 * transfer buffers to live in their own cache lines. 30 */ 31 unsigned char rxbuf[3] __aligned(IIO_DMA_MINALIGN); 32 unsigned char txbuf[3]; 33 }; 34 35 static int ltc2496_result_and_measure(struct ltc2497core_driverdata *ddata, 36 u8 address, int *val) 37 { 38 struct ltc2496_driverdata *st = 39 container_of(ddata, struct ltc2496_driverdata, common_ddata); 40 struct spi_transfer t = { 41 .tx_buf = st->txbuf, 42 .rx_buf = st->rxbuf, 43 .len = sizeof(st->txbuf), 44 }; 45 int ret; 46 47 st->txbuf[0] = LTC2497_ENABLE | address; 48 49 ret = spi_sync_transfer(st->spi, &t, 1); 50 if (ret < 0) { 51 dev_err(&st->spi->dev, "spi_sync_transfer failed: %pe\n", 52 ERR_PTR(ret)); 53 return ret; 54 } 55 56 if (val) 57 *val = ((st->rxbuf[0] & 0x3f) << 12 | 58 st->rxbuf[1] << 4 | st->rxbuf[2] >> 4) - 59 (1 << 17); 60 61 return 0; 62 } 63 64 static int ltc2496_probe(struct spi_device *spi) 65 { 66 struct iio_dev *indio_dev; 67 struct ltc2496_driverdata *st; 68 struct device *dev = &spi->dev; 69 70 indio_dev = devm_iio_device_alloc(dev, sizeof(*st)); 71 if (!indio_dev) 72 return -ENOMEM; 73 74 st = iio_priv(indio_dev); 75 spi_set_drvdata(spi, indio_dev); 76 st->spi = spi; 77 st->common_ddata.result_and_measure = ltc2496_result_and_measure; 78 st->common_ddata.chip_info = device_get_match_data(dev); 79 80 return ltc2497core_probe(dev, indio_dev); 81 } 82 83 static void ltc2496_remove(struct spi_device *spi) 84 { 85 struct iio_dev *indio_dev = spi_get_drvdata(spi); 86 87 ltc2497core_remove(indio_dev); 88 } 89 90 static const struct ltc2497_chip_info ltc2496_info = { 91 .resolution = 16, 92 .name = NULL, 93 }; 94 95 static const struct of_device_id ltc2496_of_match[] = { 96 { .compatible = "lltc,ltc2496", .data = <c2496_info, }, 97 {}, 98 }; 99 MODULE_DEVICE_TABLE(of, ltc2496_of_match); 100 101 static struct spi_driver ltc2496_driver = { 102 .driver = { 103 .name = "ltc2496", 104 .of_match_table = ltc2496_of_match, 105 }, 106 .probe = ltc2496_probe, 107 .remove = ltc2496_remove, 108 }; 109 module_spi_driver(ltc2496_driver); 110 111 MODULE_AUTHOR("Uwe Kleine-König <u.kleine-könig@pengutronix.de>"); 112 MODULE_DESCRIPTION("Linear Technology LTC2496 ADC driver"); 113 MODULE_LICENSE("GPL v2"); 114