iio: adxl372: Refactor the driver

This patch restructures the existing adxl372 driver by adding a module for
SPI and a header file, while the baseline module deals with the chip-logic.

This is a necessary step, as this driver should support in the future
a similar device which differs only in the type of interface used (I2C
instead of SPI).

Signed-off-by: Stefan Popa <stefan.popa@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

MAINTAINERS

@@ -548,6 +548,7 @@ M:	Stefan Popa <stefan.popa@analog.com>
 W:	http://ez.analog.com/community/linux-device-drivers
 S:	Supported
 F:	drivers/iio/accel/adxl372.c
+F:	drivers/iio/accel/adxl372_spi.c
 F:	Documentation/devicetree/bindings/iio/accel/adxl372.txt
 
 AF9013 MEDIA DRIVER

drivers/iio/accel/Kconfig

@@ -61,15 +61,20 @@ config ADXL345_SPI
 	  for the core module.
 
 config ADXL372
-	tristate "Analog Devices ADXL372 3-Axis Accelerometer Driver"
-	depends on SPI
+	tristate
 	select IIO_BUFFER
 	select IIO_TRIGGERED_BUFFER
+
+config ADXL372_SPI
+	tristate "Analog Devices ADXL372 3-Axis Accelerometer SPI Driver"
+	depends on SPI
+	select ADXL372
+	select REGMAP_SPI
 	help
 	  Say yes here to add support for the Analog Devices ADXL372 triaxial
 	  acceleration sensor.
 	  To compile this driver as a module, choose M here: the
-	  module will be called adxl372.
+	  module will be called adxl372_spi.
 
 config BMA180
 	tristate "Bosch BMA180/BMA250 3-Axis Accelerometer Driver"

drivers/iio/accel/Makefile

@@ -10,6 +10,7 @@ obj-$(CONFIG_ADXL345) += adxl345_core.o
 obj-$(CONFIG_ADXL345_I2C) += adxl345_i2c.o
 obj-$(CONFIG_ADXL345_SPI) += adxl345_spi.o
 obj-$(CONFIG_ADXL372) += adxl372.o
+obj-$(CONFIG_ADXL372_SPI) += adxl372_spi.o
 obj-$(CONFIG_BMA180) += bma180.o
 obj-$(CONFIG_BMA220) += bma220_spi.o
 obj-$(CONFIG_BMC150_ACCEL) += bmc150-accel-core.o

drivers/iio/accel/adxl372.c

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0+
 /*
- * ADXL372 3-Axis Digital Accelerometer SPI driver
+ * ADXL372 3-Axis Digital Accelerometer core driver
  *
  * Copyright 2018 Analog Devices Inc.
  */
@@ -20,6 +20,8 @@
 #include <linux/iio/trigger_consumer.h>
 #include <linux/iio/triggered_buffer.h>
 
+#include "adxl372.h"
+
 /* ADXL372 registers definition */
 #define ADXL372_DEVID			0x00
 #define ADXL372_DEVID_MST		0x01
@@ -246,7 +248,8 @@ static const struct iio_chan_spec adxl372_channels[] = {
 };
 
 struct adxl372_state {
-	struct spi_device		*spi;
+	int				irq;
+	struct device			*dev;
 	struct regmap			*regmap;
 	struct iio_trigger		*dready_trig;
 	enum adxl372_fifo_mode		fifo_mode;
@@ -565,7 +568,7 @@ static int adxl372_setup(struct adxl372_state *st)
 		return ret;
 
 	if (regval != ADXL372_DEVID_VAL) {
-		dev_err(&st->spi->dev, "Invalid chip id %x\n", regval);
+		dev_err(st->dev, "Invalid chip id %x\n", regval);
 		return -ENODEV;
 	}
 
@@ -891,56 +894,45 @@ static const struct iio_info adxl372_info = {
 	.hwfifo_set_watermark = adxl372_set_watermark,
 };
 
-static bool adxl372_readable_noinc_reg(struct device *dev, unsigned int reg)
+bool adxl372_readable_noinc_reg(struct device *dev, unsigned int reg)
 {
 	return (reg == ADXL372_FIFO_DATA);
 }
+EXPORT_SYMBOL_GPL(adxl372_readable_noinc_reg);
 
-static const struct regmap_config adxl372_spi_regmap_config = {
-	.reg_bits = 7,
-	.pad_bits = 1,
-	.val_bits = 8,
-	.read_flag_mask = BIT(0),
-	.readable_noinc_reg = adxl372_readable_noinc_reg,
-};
-
-static int adxl372_probe(struct spi_device *spi)
+int adxl372_probe(struct device *dev, struct regmap *regmap,
+		  int irq, const char *name)
 {
 	struct iio_dev *indio_dev;
 	struct adxl372_state *st;
-	struct regmap *regmap;
 	int ret;
 
-	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
+	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;
-
-	regmap = devm_regmap_init_spi(spi, &adxl372_spi_regmap_config);
-	if (IS_ERR(regmap))
-		return PTR_ERR(regmap);
+	dev_set_drvdata(dev, indio_dev);
 
+	st->dev = dev;
 	st->regmap = regmap;
+	st->irq = irq;
 
 	indio_dev->channels = adxl372_channels;
 	indio_dev->num_channels = ARRAY_SIZE(adxl372_channels);
 	indio_dev->available_scan_masks = adxl372_channel_masks;
-	indio_dev->dev.parent = &spi->dev;
-	indio_dev->name = spi_get_device_id(spi)->name;
+	indio_dev->dev.parent = dev;
+	indio_dev->name = name;
 	indio_dev->info = &adxl372_info;
 	indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_SOFTWARE;
 
 	ret = adxl372_setup(st);
 	if (ret < 0) {
-		dev_err(&st->spi->dev, "ADXL372 setup failed\n");
+		dev_err(dev, "ADXL372 setup failed\n");
 		return ret;
 	}
 
-	ret = devm_iio_triggered_buffer_setup(&st->spi->dev,
+	ret = devm_iio_triggered_buffer_setup(dev,
 					      indio_dev, NULL,
 					      adxl372_trigger_handler,
 					      &adxl372_buffer_ops);
@@ -949,8 +941,8 @@ static int adxl372_probe(struct spi_device *spi)
 
 	iio_buffer_set_attrs(indio_dev->buffer, adxl372_fifo_attributes);
 
-	if (st->spi->irq) {
-		st->dready_trig = devm_iio_trigger_alloc(&st->spi->dev,
+	if (st->irq) {
+		st->dready_trig = devm_iio_trigger_alloc(dev,
 							 "%s-dev%d",
 							 indio_dev->name,
 							 indio_dev->id);
@@ -958,15 +950,15 @@ static int adxl372_probe(struct spi_device *spi)
 			return -ENOMEM;
 
 		st->dready_trig->ops = &adxl372_trigger_ops;
-		st->dready_trig->dev.parent = &st->spi->dev;
+		st->dready_trig->dev.parent = dev;
 		iio_trigger_set_drvdata(st->dready_trig, indio_dev);
-		ret = devm_iio_trigger_register(&st->spi->dev, st->dready_trig);
+		ret = devm_iio_trigger_register(dev, st->dready_trig);
 		if (ret < 0)
 			return ret;
 
 		indio_dev->trig = iio_trigger_get(st->dready_trig);
 
-		ret = devm_request_threaded_irq(&st->spi->dev, st->spi->irq,
+		ret = devm_request_threaded_irq(dev, st->irq,
 					iio_trigger_generic_data_rdy_poll,
 					NULL,
 					IRQF_TRIGGER_RISING | IRQF_ONESHOT,
@@ -975,24 +967,9 @@ static int adxl372_probe(struct spi_device *spi)
 			return ret;
 	}
 
-	return devm_iio_device_register(&st->spi->dev, indio_dev);
+	return devm_iio_device_register(dev, indio_dev);
 }
-
-static const struct spi_device_id adxl372_id[] = {
-	{ "adxl372", 0 },
-	{}
-};
-MODULE_DEVICE_TABLE(spi, adxl372_id);
-
-static struct spi_driver adxl372_driver = {
-	.driver = {
-		.name = KBUILD_MODNAME,
-	},
-	.probe = adxl372_probe,
-	.id_table = adxl372_id,
-};
-
-module_spi_driver(adxl372_driver);
+EXPORT_SYMBOL_GPL(adxl372_probe);
 
 MODULE_AUTHOR("Stefan Popa <stefan.popa@analog.com>");
 MODULE_DESCRIPTION("Analog Devices ADXL372 3-axis accelerometer driver");

drivers/iio/accel/adxl372.h

@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * ADXL372 3-Axis Digital Accelerometer
+ *
+ * Copyright 2018 Analog Devices Inc.
+ */
+
+#ifndef _ADXL372_H_
+#define _ADXL372_H_
+
+int adxl372_probe(struct device *dev, struct regmap *regmap,
+		  int irq, const char *name);
+bool adxl372_readable_noinc_reg(struct device *dev, unsigned int reg);
+
+#endif /* _ADXL372_H_ */

drivers/iio/accel/adxl372_spi.c

@@ -0,0 +1,52 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * ADXL372 3-Axis Digital Accelerometer SPI driver
+ *
+ * Copyright 2018 Analog Devices Inc.
+ */
+
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+
+#include "adxl372.h"
+
+static const struct regmap_config adxl372_spi_regmap_config = {
+	.reg_bits = 7,
+	.pad_bits = 1,
+	.val_bits = 8,
+	.read_flag_mask = BIT(0),
+	.readable_noinc_reg = adxl372_readable_noinc_reg,
+};
+
+static int adxl372_spi_probe(struct spi_device *spi)
+{
+	const struct spi_device_id *id = spi_get_device_id(spi);
+	struct regmap *regmap;
+
+	regmap = devm_regmap_init_spi(spi, &adxl372_spi_regmap_config);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	return adxl372_probe(&spi->dev, regmap, spi->irq, id->name);
+}
+
+static const struct spi_device_id adxl372_spi_id[] = {
+	{ "adxl372", 0 },
+	{}
+};
+MODULE_DEVICE_TABLE(spi, adxl372_spi_id);
+
+static struct spi_driver adxl372_spi_driver = {
+	.driver = {
+		.name = "adxl372_spi",
+	},
+	.probe = adxl372_spi_probe,
+	.id_table = adxl372_spi_id,
+};
+
+module_spi_driver(adxl372_spi_driver);
+
+MODULE_AUTHOR("Stefan Popa <stefan.popa@analog.com>");
+MODULE_DESCRIPTION("Analog Devices ADXL372 3-axis accelerometer SPI driver");
+MODULE_LICENSE("GPL");