forked from Minki/linux
69548b7c2c
This allows to share most of this driver for the ltc2496 driver added in the next commit that is an SPI variant of the ltc2497. Initially I named the generic part ltc249x, but wild card names are frowned upon, so the generic part is called ltc2497-core even though it's not obvious that this is then to be reused for the ltc2496 driver. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
112 lines
2.7 KiB
C
112 lines
2.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* ltc2497.c - Driver for Analog Devices/Linear Technology LTC2497 ADC
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*
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* Copyright (C) 2017 Analog Devices Inc.
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*
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* Datasheet: http://cds.linear.com/docs/en/datasheet/2497fd.pdf
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*/
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#include <linux/i2c.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/driver.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include "ltc2497.h"
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struct ltc2497_driverdata {
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/* this must be the first member */
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struct ltc2497core_driverdata common_ddata;
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struct i2c_client *client;
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/*
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* DMA (thus cache coherency maintenance) requires the
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* transfer buffers to live in their own cache lines.
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*/
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__be32 buf ____cacheline_aligned;
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};
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static int ltc2497_result_and_measure(struct ltc2497core_driverdata *ddata,
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u8 address, int *val)
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{
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struct ltc2497_driverdata *st =
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container_of(ddata, struct ltc2497_driverdata, common_ddata);
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int ret;
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if (val) {
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ret = i2c_master_recv(st->client, (char *)&st->buf, 3);
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if (ret < 0) {
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dev_err(&st->client->dev, "i2c_master_recv failed\n");
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return ret;
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}
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*val = (be32_to_cpu(st->buf) >> 14) - (1 << 17);
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}
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ret = i2c_smbus_write_byte(st->client,
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LTC2497_ENABLE | address);
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if (ret)
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dev_err(&st->client->dev, "i2c transfer failed: %pe\n",
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ERR_PTR(ret));
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return ret;
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}
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static int ltc2497_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct iio_dev *indio_dev;
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struct ltc2497_driverdata *st;
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struct device *dev = &client->dev;
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C |
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I2C_FUNC_SMBUS_WRITE_BYTE))
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return -EOPNOTSUPP;
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indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
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if (!indio_dev)
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return -ENOMEM;
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st = iio_priv(indio_dev);
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i2c_set_clientdata(client, indio_dev);
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st->client = client;
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st->common_ddata.result_and_measure = ltc2497_result_and_measure;
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return ltc2497core_probe(dev, indio_dev);
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}
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static int ltc2497_remove(struct i2c_client *client)
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{
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struct iio_dev *indio_dev = i2c_get_clientdata(client);
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ltc2497core_remove(indio_dev);
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return 0;
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}
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static const struct i2c_device_id ltc2497_id[] = {
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{ "ltc2497", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, ltc2497_id);
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static const struct of_device_id ltc2497_of_match[] = {
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{ .compatible = "lltc,ltc2497", },
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{},
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};
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MODULE_DEVICE_TABLE(of, ltc2497_of_match);
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static struct i2c_driver ltc2497_driver = {
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.driver = {
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.name = "ltc2497",
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.of_match_table = of_match_ptr(ltc2497_of_match),
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},
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.probe = ltc2497_probe,
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.remove = ltc2497_remove,
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.id_table = ltc2497_id,
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};
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module_i2c_driver(ltc2497_driver);
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MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
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MODULE_DESCRIPTION("Linear Technology LTC2497 ADC driver");
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MODULE_LICENSE("GPL v2");
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