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authorUwe Kleine-König <u.kleine-koenig@pengutronix.de>2019-12-09 21:32:48 +0100
committerJonathan Cameron <Jonathan.Cameron@huawei.com>2019-12-15 12:15:19 +0000
commite4c5c4dfaa88e49f33e8c11b52c65c630c0b12a7 (patch)
treede460d283b9573d2c9a9865b142dbc864fb354e2 /drivers/iio/adc
parent69548b7c2c4f1ab9a135f2050d9683c7691ef701 (diff)
downloadlinux-e4c5c4dfaa88e49f33e8c11b52c65c630c0b12a7.tar.gz
iio: adc: new driver to support Linear technology's ltc2496
This chip is similar to the LTC2497 ADC, it just uses SPI instead of I2C and so has a slightly different protocol. Only the actual hardware access is different. The spi protocol is different enough to not be able to map the differences via a regmap. Also generalize the entry in MAINTAINER to cover the newly introduced file. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Diffstat (limited to 'drivers/iio/adc')
-rw-r--r--drivers/iio/adc/Kconfig10
-rw-r--r--drivers/iio/adc/Makefile1
-rw-r--r--drivers/iio/adc/ltc2496.c108
3 files changed, 119 insertions, 0 deletions
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 27bb4e56eaea..82e33082958c 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -530,6 +530,16 @@ config LTC2485
To compile this driver as a module, choose M here: the module will be
called ltc2485.
+config LTC2496
+ tristate "Linear Technology LTC2496 ADC driver"
+ depends on SPI
+ help
+ Say yes here to build support for Linear Technology LTC2496
+ 16-Bit 8-/16-Channel Delta Sigma ADC.
+
+ To compile this driver as a module, choose M here: the module will be
+ called ltc2496.
+
config LTC2497
tristate "Linear Technology LTC2497 ADC driver"
depends on I2C
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 5f8d7ac6bbe2..919228900df9 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -51,6 +51,7 @@ obj-$(CONFIG_LPC18XX_ADC) += lpc18xx_adc.o
obj-$(CONFIG_LPC32XX_ADC) += lpc32xx_adc.o
obj-$(CONFIG_LTC2471) += ltc2471.o
obj-$(CONFIG_LTC2485) += ltc2485.o
+obj-$(CONFIG_LTC2496) += ltc2496.o ltc2497-core.o
obj-$(CONFIG_LTC2497) += ltc2497.o ltc2497-core.o
obj-$(CONFIG_MAX1027) += max1027.o
obj-$(CONFIG_MAX11100) += max11100.o
diff --git a/drivers/iio/adc/ltc2496.c b/drivers/iio/adc/ltc2496.c
new file mode 100644
index 000000000000..88a30156a849
--- /dev/null
+++ b/drivers/iio/adc/ltc2496.c
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ltc2496.c - Driver for Analog Devices/Linear Technology LTC2496 ADC
+ *
+ * Based on ltc2497.c which has
+ * Copyright (C) 2017 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2.
+ *
+ * Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/2496fc.pdf
+ */
+
+#include <linux/spi/spi.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/driver.h>
+#include <linux/module.h>
+#include <linux/of.h>
+
+#include "ltc2497.h"
+
+struct ltc2496_driverdata {
+ /* this must be the first member */
+ struct ltc2497core_driverdata common_ddata;
+ struct spi_device *spi;
+
+ /*
+ * DMA (thus cache coherency maintenance) requires the
+ * transfer buffers to live in their own cache lines.
+ */
+ unsigned char rxbuf[3] ____cacheline_aligned;
+ unsigned char txbuf[3];
+};
+
+static int ltc2496_result_and_measure(struct ltc2497core_driverdata *ddata,
+ u8 address, int *val)
+{
+ struct ltc2496_driverdata *st =
+ container_of(ddata, struct ltc2496_driverdata, common_ddata);
+ struct spi_transfer t = {
+ .tx_buf = st->txbuf,
+ .rx_buf = st->rxbuf,
+ .len = sizeof(st->txbuf),
+ };
+ int ret;
+
+ st->txbuf[0] = LTC2497_ENABLE | address;
+
+ ret = spi_sync_transfer(st->spi, &t, 1);
+ if (ret < 0) {
+ dev_err(&st->spi->dev, "spi_sync_transfer failed: %pe\n",
+ ERR_PTR(ret));
+ return ret;
+ }
+
+ if (val)
+ *val = ((st->rxbuf[0] & 0x3f) << 12 |
+ st->rxbuf[1] << 4 | st->rxbuf[2] >> 4) -
+ (1 << 17);
+
+ return 0;
+}
+
+static int ltc2496_probe(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev;
+ struct ltc2496_driverdata *st;
+ struct device *dev = &spi->dev;
+
+ indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ st = iio_priv(indio_dev);
+ spi_set_drvdata(spi, indio_dev);
+ st->spi = spi;
+ st->common_ddata.result_and_measure = ltc2496_result_and_measure;
+
+ return ltc2497core_probe(dev, indio_dev);
+}
+
+static int ltc2496_remove(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev = spi_get_drvdata(spi);
+
+ ltc2497core_remove(indio_dev);
+
+ return 0;
+}
+
+static const struct of_device_id ltc2496_of_match[] = {
+ { .compatible = "lltc,ltc2496", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, ltc2496_of_match);
+
+static struct spi_driver ltc2496_driver = {
+ .driver = {
+ .name = "ltc2496",
+ .of_match_table = of_match_ptr(ltc2496_of_match),
+ },
+ .probe = ltc2496_probe,
+ .remove = ltc2496_remove,
+};
+module_spi_driver(ltc2496_driver);
+
+MODULE_AUTHOR("Uwe Kleine-König <u.kleine-könig@pengutronix.de>");
+MODULE_DESCRIPTION("Linear Technology LTC2496 ADC driver");
+MODULE_LICENSE("GPL v2");