1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * ltc2497.c - Driver for Analog Devices/Linear Technology LTC2497 ADC 4 * 5 * Copyright (C) 2017 Analog Devices Inc. 6 * 7 * Datasheet: http://cds.linear.com/docs/en/datasheet/2497fd.pdf 8 */ 9 10 #include <linux/i2c.h> 11 #include <linux/iio/iio.h> 12 #include <linux/iio/driver.h> 13 #include <linux/module.h> 14 #include <linux/of.h> 15 16 #include "ltc2497.h" 17 18 struct ltc2497_driverdata { 19 /* this must be the first member */ 20 struct ltc2497core_driverdata common_ddata; 21 struct i2c_client *client; 22 /* 23 * DMA (thus cache coherency maintenance) requires the 24 * transfer buffers to live in their own cache lines. 25 */ 26 __be32 buf ____cacheline_aligned; 27 }; 28 29 static int ltc2497_result_and_measure(struct ltc2497core_driverdata *ddata, 30 u8 address, int *val) 31 { 32 struct ltc2497_driverdata *st = 33 container_of(ddata, struct ltc2497_driverdata, common_ddata); 34 int ret; 35 36 if (val) { 37 ret = i2c_master_recv(st->client, (char *)&st->buf, 3); 38 if (ret < 0) { 39 dev_err(&st->client->dev, "i2c_master_recv failed\n"); 40 return ret; 41 } 42 43 *val = (be32_to_cpu(st->buf) >> 14) - (1 << 17); 44 } 45 46 ret = i2c_smbus_write_byte(st->client, 47 LTC2497_ENABLE | address); 48 if (ret) 49 dev_err(&st->client->dev, "i2c transfer failed: %pe\n", 50 ERR_PTR(ret)); 51 return ret; 52 } 53 54 static int ltc2497_probe(struct i2c_client *client, 55 const struct i2c_device_id *id) 56 { 57 struct iio_dev *indio_dev; 58 struct ltc2497_driverdata *st; 59 struct device *dev = &client->dev; 60 61 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C | 62 I2C_FUNC_SMBUS_WRITE_BYTE)) 63 return -EOPNOTSUPP; 64 65 indio_dev = devm_iio_device_alloc(dev, sizeof(*st)); 66 if (!indio_dev) 67 return -ENOMEM; 68 69 st = iio_priv(indio_dev); 70 i2c_set_clientdata(client, indio_dev); 71 st->client = client; 72 st->common_ddata.result_and_measure = ltc2497_result_and_measure; 73 74 return ltc2497core_probe(dev, indio_dev); 75 } 76 77 static int ltc2497_remove(struct i2c_client *client) 78 { 79 struct iio_dev *indio_dev = i2c_get_clientdata(client); 80 81 ltc2497core_remove(indio_dev); 82 83 return 0; 84 } 85 86 static const struct i2c_device_id ltc2497_id[] = { 87 { "ltc2497", 0 }, 88 { } 89 }; 90 MODULE_DEVICE_TABLE(i2c, ltc2497_id); 91 92 static const struct of_device_id ltc2497_of_match[] = { 93 { .compatible = "lltc,ltc2497", }, 94 {}, 95 }; 96 MODULE_DEVICE_TABLE(of, ltc2497_of_match); 97 98 static struct i2c_driver ltc2497_driver = { 99 .driver = { 100 .name = "ltc2497", 101 .of_match_table = of_match_ptr(ltc2497_of_match), 102 }, 103 .probe = ltc2497_probe, 104 .remove = ltc2497_remove, 105 .id_table = ltc2497_id, 106 }; 107 module_i2c_driver(ltc2497_driver); 108 109 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>"); 110 MODULE_DESCRIPTION("Linear Technology LTC2497 ADC driver"); 111 MODULE_LICENSE("GPL v2"); 112