spi: dw: Discard dma_width member of the dw_spi structure

This member has exactly the same value as n_bytes of the DW SPI private
data object, it's calculated at the same point of the transfer method,
n_bytes isn't changed during the whole transfer, and they even serve for
the same purpose - keep number of bytes per transfer word, though the
dma_width is used only to calculate the DMA source/destination addresses
width, which n_bytes could be also utilized for. Taking all of these
into account let's replace the dma_width member usage with n_bytes one
and remove the former.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Georgy Vlasov <Georgy.Vlasov@baikalelectronics.ru>
Cc: Ramil Zaripov <Ramil.Zaripov@baikalelectronics.ru>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: devicetree@vger.kernel.org

Link: https://lore.kernel.org/r/20200522000806.7381-6-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-dw-mid.c

@@ -133,10 +133,10 @@ static bool mid_spi_can_dma(struct spi_controller *master,
 	return xfer->len > dws->fifo_len;
 }
 
-static enum dma_slave_buswidth convert_dma_width(u32 dma_width) {
-	if (dma_width == 1)
+static enum dma_slave_buswidth convert_dma_width(u8 n_bytes) {
+	if (n_bytes == 1)
 		return DMA_SLAVE_BUSWIDTH_1_BYTE;
-	else if (dma_width == 2)
+	else if (n_bytes == 2)
 		return DMA_SLAVE_BUSWIDTH_2_BYTES;
 
 	return DMA_SLAVE_BUSWIDTH_UNDEFINED;
@@ -172,7 +172,7 @@ static struct dma_async_tx_descriptor *dw_spi_dma_prepare_tx(struct dw_spi *dws,
 	txconf.dst_addr = dws->dma_addr;
 	txconf.dst_maxburst = 16;
 	txconf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
-	txconf.dst_addr_width = convert_dma_width(dws->dma_width);
+	txconf.dst_addr_width = convert_dma_width(dws->n_bytes);
 	txconf.device_fc = false;
 
 	dmaengine_slave_config(dws->txchan, &txconf);
@@ -221,7 +221,7 @@ static struct dma_async_tx_descriptor *dw_spi_dma_prepare_rx(struct dw_spi *dws,
 	rxconf.src_addr = dws->dma_addr;
 	rxconf.src_maxburst = 16;
 	rxconf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
-	rxconf.src_addr_width = convert_dma_width(dws->dma_width);
+	rxconf.src_addr_width = convert_dma_width(dws->n_bytes);
 	rxconf.device_fc = false;
 
 	dmaengine_slave_config(dws->rxchan, &rxconf);

drivers/spi/spi-dw.c

@@ -353,7 +353,6 @@ static int dw_spi_transfer_one(struct spi_controller *master,
 	}
 
 	dws->n_bytes = DIV_ROUND_UP(transfer->bits_per_word, BITS_PER_BYTE);
-	dws->dma_width = DIV_ROUND_UP(transfer->bits_per_word, BITS_PER_BYTE);
 
 	cr0 = dws->update_cr0(master, spi, transfer);
 	dw_writel(dws, DW_SPI_CTRLR0, cr0);

drivers/spi/spi-dw.h

@@ -136,7 +136,6 @@ struct dw_spi {
 	void			*rx_end;
 	int			dma_mapped;
 	u8			n_bytes;	/* current is a 1/2 bytes op */
-	u32			dma_width;
 	irqreturn_t		(*transfer_handler)(struct dw_spi *dws);
 	u32			current_freq;	/* frequency in hz */