iio: accel: kxsd9: Split out SPI transport

This moves the KXSD9 SPI transport out to its own file and Kconfig
entry, so that we will be able to add another transport method.
We export the common probe and add a local header file for the
functionality shared between the main driver and the transport
driver.

We make the SPI transport the default for the driver if SPI is
available and the KXSD9 driver was selected, so the oldconfig
upgrade path will be clear.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

1 files changed, 110 insertions, 0 deletions

diff --git a/drivers/iio/accel/kxsd9-spi.c b/drivers/iio/accel/kxsd9-spi.c
new file mode 100644
index 000000000000..ec9d00d5340f
--- /dev/null
+++ b/drivers/iio/accel/kxsd9-spi.c
@@ -0,0 +1,110 @@
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/spi/spi.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include "kxsd9.h"
+
+#define KXSD9_READ(a) (0x80 | (a))
+#define KXSD9_WRITE(a) (a)
+
+static int kxsd9_spi_readreg(struct kxsd9_transport *tr, u8 address)
+{
+	struct spi_device *spi = tr->trdev;
+
+	return spi_w8r8(spi, KXSD9_READ(address));
+}
+
+static int kxsd9_spi_writereg(struct kxsd9_transport *tr, u8 address, u8 val)
+{
+	struct spi_device *spi = tr->trdev;
+
+	tr->tx[0] = KXSD9_WRITE(address),
+	tr->tx[1] = val;
+	return spi_write(spi, tr->tx, 2);
+}
+
+static int kxsd9_spi_write2(struct kxsd9_transport *tr, u8 b1, u8 b2)
+{
+	struct spi_device *spi = tr->trdev;
+
+	tr->tx[0] = b1;
+	tr->tx[1] = b2;
+	return spi_write(spi, tr->tx, 2);
+}
+
+static int kxsd9_spi_readval(struct kxsd9_transport *tr, u8 address)
+{
+	struct spi_device *spi = tr->trdev;
+	struct spi_transfer xfers[] = {
+		{
+			.bits_per_word = 8,
+			.len = 1,
+			.delay_usecs = 200,
+			.tx_buf = tr->tx,
+		}, {
+			.bits_per_word = 8,
+			.len = 2,
+			.rx_buf = tr->rx,
+		},
+	};
+	int ret;
+
+	tr->tx[0] = KXSD9_READ(address);
+	ret = spi_sync_transfer(spi, xfers, ARRAY_SIZE(xfers));
+	if (!ret)
+		ret = (((u16)(tr->rx[0])) << 8) | (tr->rx[1]);
+	return ret;
+}
+
+static int kxsd9_spi_probe(struct spi_device *spi)
+{
+	struct kxsd9_transport *transport;
+	int ret;
+
+	transport = devm_kzalloc(&spi->dev, sizeof(*transport), GFP_KERNEL);
+	if (!transport)
+		return -ENOMEM;
+
+	transport->trdev = spi;
+	transport->readreg = kxsd9_spi_readreg;
+	transport->writereg = kxsd9_spi_writereg;
+	transport->write2 = kxsd9_spi_write2;
+	transport->readval = kxsd9_spi_readval;
+	spi->mode = SPI_MODE_0;
+	spi_setup(spi);
+
+	ret = kxsd9_common_probe(&spi->dev,
+				 transport,
+				 spi_get_device_id(spi)->name);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int kxsd9_spi_remove(struct spi_device *spi)
+{
+	return kxsd9_common_remove(&spi->dev);
+}
+
+static const struct spi_device_id kxsd9_spi_id[] = {
+	{"kxsd9", 0},
+	{ },
+};
+MODULE_DEVICE_TABLE(spi, kxsd9_spi_id);
+
+static struct spi_driver kxsd9_spi_driver = {
+	.driver = {
+		.name = "kxsd9",
+	},
+	.probe = kxsd9_spi_probe,
+	.remove = kxsd9_spi_remove,
+	.id_table = kxsd9_spi_id,
+};
+module_spi_driver(kxsd9_spi_driver);
+
+MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
+MODULE_DESCRIPTION("Kionix KXSD9 SPI driver");
+MODULE_LICENSE("GPL v2");