iio: accel: kxsd9: Split out transport mechanism

Split off a transport mechanism struct that will deal with the SPI
traffic in preparation for adding I2C support.

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

diff --git a/drivers/iio/accel/kxsd9.c b/drivers/iio/accel/kxsd9.c
index 9d72d4b..df8a31e 100644 (file)
--- a/drivers/iio/accel/kxsd9.c
+++ b/drivers/iio/accel/kxsd9.c
@@ -43,18 +43,36 @@
 
 #define KXSD9_STATE_RX_SIZE 2
 #define KXSD9_STATE_TX_SIZE 2
+
+struct kxsd9_transport;
+
+/**
+ * struct kxsd9_transport - transport adapter for SPI or I2C
+ * @trdev: transport device such as SPI or I2C
+ * @write1(): function to write a byte to the device
+ * @write2(): function to write two consecutive bytes to the device
+ * @readval(): function to read a 16bit value from the device
+ * @rx: cache aligned read buffer
+ * @tx: cache aligned write buffer
+ */
+struct kxsd9_transport {
+       void *trdev;
+       int (*write1) (struct kxsd9_transport *tr, u8 byte);
+       int (*write2) (struct kxsd9_transport *tr, u8 b1, u8 b2);
+       int (*readval) (struct kxsd9_transport *tr, u8 address);
+       u8 rx[KXSD9_STATE_RX_SIZE] ____cacheline_aligned;
+       u8 tx[KXSD9_STATE_TX_SIZE];
+};
+
 /**
  * struct kxsd9_state - device related storage
+ * @transport: transport for the KXSD9
  * @buf_lock:  protect the rx and tx buffers.
  * @us:                spi device
- * @rx:                single rx buffer storage
- * @tx:                single tx buffer storage
  **/
 struct kxsd9_state {
+       struct kxsd9_transport *transport;
        struct mutex buf_lock;
-       struct spi_device *us;
-       u8 rx[KXSD9_STATE_RX_SIZE] ____cacheline_aligned;
-       u8 tx[KXSD9_STATE_TX_SIZE];
 };
 
 #define KXSD9_SCALE_2G "0.011978"
@@ -80,13 +98,12 @@ static int kxsd9_write_scale(struct iio_dev *indio_dev, int micro)
                return -EINVAL;
 
        mutex_lock(&st->buf_lock);
-       ret = spi_w8r8(st->us, KXSD9_READ(KXSD9_REG_CTRL_C));
-       if (ret < 0)
+       ret = st->transport->write1(st->transport, KXSD9_READ(KXSD9_REG_CTRL_C));
+       if (ret)
                goto error_ret;
-       st->tx[0] = KXSD9_WRITE(KXSD9_REG_CTRL_C);
-       st->tx[1] = (ret & ~KXSD9_FS_MASK) | i;
-
-       ret = spi_write(st->us, st->tx, 2);
+       ret = st->transport->write2(st->transport,
+                                   KXSD9_WRITE(KXSD9_REG_CTRL_C),
+                                   (ret & ~KXSD9_FS_MASK) | i);
 error_ret:
        mutex_unlock(&st->buf_lock);
        return ret;
@@ -96,24 +113,9 @@ static int kxsd9_read(struct iio_dev *indio_dev, u8 address)
 {
        int ret;
        struct kxsd9_state *st = iio_priv(indio_dev);
-       struct spi_transfer xfers[] = {
-               {
-                       .bits_per_word = 8,
-                       .len = 1,
-                       .delay_usecs = 200,
-                       .tx_buf = st->tx,
-               }, {
-                       .bits_per_word = 8,
-                       .len = 2,
-                       .rx_buf = st->rx,
-               },
-       };
 
        mutex_lock(&st->buf_lock);
-       st->tx[0] = KXSD9_READ(address);
-       ret = spi_sync_transfer(st->us, xfers, ARRAY_SIZE(xfers));
-       if (!ret)
-               ret = (((u16)(st->rx[0])) << 8) | (st->rx[1] & 0xF0);
+       ret = st->transport->readval(st->transport, KXSD9_READ(address));
        mutex_unlock(&st->buf_lock);
        return ret;
 }
@@ -163,8 +165,8 @@ static int kxsd9_read_raw(struct iio_dev *indio_dev,
                ret = IIO_VAL_INT;
                break;
        case IIO_CHAN_INFO_SCALE:
-               ret = spi_w8r8(st->us, KXSD9_READ(KXSD9_REG_CTRL_C));
-               if (ret < 0)
+               ret = st->transport->write1(st->transport, KXSD9_READ(KXSD9_REG_CTRL_C));
+               if (ret)
                        goto error_ret;
                *val = 0;
                *val2 = kxsd9_micro_scales[ret & KXSD9_FS_MASK];
@@ -203,15 +205,10 @@ static int kxsd9_power_up(struct kxsd9_state *st)
 {
        int ret;
 
-       st->tx[0] = 0x0d;
-       st->tx[1] = 0x40;
-       ret = spi_write(st->us, st->tx, 2);
+       ret = st->transport->write2(st->transport, 0x0d, 0x40);
        if (ret)
                return ret;
-
-       st->tx[0] = 0x0c;
-       st->tx[1] = 0x9b;
-       return spi_write(st->us, st->tx, 2);
+       return st->transport->write2(st->transport, 0x0c, 0x9b);
 };
 
 static const struct iio_info kxsd9_info = {
@@ -221,56 +218,130 @@ static const struct iio_info kxsd9_info = {
        .driver_module = THIS_MODULE,
 };
 
-static int kxsd9_probe(struct spi_device *spi)
+static int kxsd9_common_probe(struct device *parent,
+                             struct kxsd9_transport *transport,
+                             const char *name,
+                             struct iio_dev **retdev)
 {
        struct iio_dev *indio_dev;
        struct kxsd9_state *st;
+       int ret;
 
-       indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
+       indio_dev = devm_iio_device_alloc(parent, sizeof(*st));
        if (!indio_dev)
                return -ENOMEM;
 
        st = iio_priv(indio_dev);
-       spi_set_drvdata(spi, indio_dev);
+       st->transport = transport;
 
-       st->us = spi;
        mutex_init(&st->buf_lock);
        indio_dev->channels = kxsd9_channels;
        indio_dev->num_channels = ARRAY_SIZE(kxsd9_channels);
-       indio_dev->name = spi_get_device_id(spi)->name;
-       indio_dev->dev.parent = &spi->dev;
+       indio_dev->name = name;
+       indio_dev->dev.parent = parent;
        indio_dev->info = &kxsd9_info;
        indio_dev->modes = INDIO_DIRECT_MODE;
 
+       kxsd9_power_up(st);
+
+       ret = iio_device_register(indio_dev);
+       if (ret)
+               return ret;
+
+       *retdev = indio_dev;
+       return 0;
+}
+
+static int kxsd9_spi_write1(struct kxsd9_transport *tr, u8 byte)
+{
+       struct spi_device *spi = tr->trdev;
+
+       return spi_w8r8(spi, byte);
+}
+
+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] = address;
+       ret = spi_sync_transfer(spi, xfers, ARRAY_SIZE(xfers));
+       if (!ret)
+               ret = (((u16)(tr->rx[0])) << 8) | (tr->rx[1] & 0xF0);
+       return ret;
+}
+
+static int kxsd9_spi_probe(struct spi_device *spi)
+{
+       struct kxsd9_transport *transport;
+       struct iio_dev *indio_dev;
+       int ret;
+
+       transport = devm_kzalloc(&spi->dev, sizeof(*transport), GFP_KERNEL);
+       if (!transport)
+               return -ENOMEM;
+
+       transport->trdev = spi;
+       transport->write1 = kxsd9_spi_write1;
+       transport->write2 = kxsd9_spi_write2;
+       transport->readval = kxsd9_spi_readval;
        spi->mode = SPI_MODE_0;
        spi_setup(spi);
-       kxsd9_power_up(st);
 
-       return iio_device_register(indio_dev);
+       ret = kxsd9_common_probe(&spi->dev,
+                                transport,
+                                spi_get_device_id(spi)->name,
+                                &indio_dev);
+       if (ret)
+               return ret;
+
+       spi_set_drvdata(spi, indio_dev);
+       return 0;
 }
 
-static int kxsd9_remove(struct spi_device *spi)
+static int kxsd9_spi_remove(struct spi_device *spi)
 {
        iio_device_unregister(spi_get_drvdata(spi));
 
        return 0;
 }
 
-static const struct spi_device_id kxsd9_id[] = {
+static const struct spi_device_id kxsd9_spi_id[] = {
        {"kxsd9", 0},
        { },
 };
-MODULE_DEVICE_TABLE(spi, kxsd9_id);
+MODULE_DEVICE_TABLE(spi, kxsd9_spi_id);
 
-static struct spi_driver kxsd9_driver = {
+static struct spi_driver kxsd9_spi_driver = {
        .driver = {
                .name = "kxsd9",
        },
-       .probe = kxsd9_probe,
-       .remove = kxsd9_remove,
-       .id_table = kxsd9_id,
+       .probe = kxsd9_spi_probe,
+       .remove = kxsd9_spi_remove,
+       .id_table = kxsd9_spi_id,
 };
-module_spi_driver(kxsd9_driver);
+module_spi_driver(kxsd9_spi_driver);
 
 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
 MODULE_DESCRIPTION("Kionix KXSD9 SPI driver");