spi: Use void pointers for data in simple SPI I/O operations

Currently the simple SPI I/O operations all take pointers to u8 * buffers
to operate on. This creates needless type compatibility issues and the
underlying spi_transfer structure uses void pointers anyway so convert the
API over to take void pointers too.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

drivers/spi/spi.c

@@ -1047,8 +1047,8 @@ static u8	*buf;
  * spi_{async,sync}() calls with dma-safe buffers.
  */
 int spi_write_then_read(struct spi_device *spi,
-		const u8 *txbuf, unsigned n_tx,
-		u8 *rxbuf, unsigned n_rx)
+		const void *txbuf, unsigned n_tx,
+		void *rxbuf, unsigned n_rx)
 {
 	static DEFINE_MUTEX(lock);
 

include/linux/spi/spi.h

@@ -581,7 +581,7 @@ extern int spi_bus_unlock(struct spi_master *master);
  * Callable only from contexts that can sleep.
  */
 static inline int
-spi_write(struct spi_device *spi, const u8 *buf, size_t len)
+spi_write(struct spi_device *spi, const void *buf, size_t len)
 {
 	struct spi_transfer	t = {
 			.tx_buf		= buf,
@@ -605,7 +605,7 @@ spi_write(struct spi_device *spi, const u8 *buf, size_t len)
  * Callable only from contexts that can sleep.
  */
 static inline int
-spi_read(struct spi_device *spi, u8 *buf, size_t len)
+spi_read(struct spi_device *spi, void *buf, size_t len)
 {
 	struct spi_transfer	t = {
 			.rx_buf		= buf,
@@ -620,8 +620,8 @@ spi_read(struct spi_device *spi, u8 *buf, size_t len)
 
 /* this copies txbuf and rxbuf data; for small transfers only! */
 extern int spi_write_then_read(struct spi_device *spi,
-		const u8 *txbuf, unsigned n_tx,
-		u8 *rxbuf, unsigned n_rx);
+		const void *txbuf, unsigned n_tx,
+		void *rxbuf, unsigned n_rx);
 
 /**
  * spi_w8r8 - SPI synchronous 8 bit write followed by 8 bit read