spi: spi-ep93xx: add spi master prepare_transfer_hardware()

This driver currently enables the hardware at the start of every
message and disabled it when the message is complete. Make it a
bit smarter by adding the prepare_transfer_hardware() and
unprepare_transfer_hardware() callbacks so that the core can
enable/disable the hardware based on spi message queue.
Signed-off-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
[chris: use u32 instead of unsigned int]
Signed-off-by: NChris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

drivers/spi/spi-ep93xx.c

@@ -111,33 +111,6 @@ struct ep93xx_spi {
 /* converts bits per word to CR0.DSS value */
 #define bits_per_word_to_dss(bpw)	((bpw) - 1)
 
-static int ep93xx_spi_enable(const struct ep93xx_spi *espi)
-{
-	u32 val;
-	int err;
-
-	err = clk_enable(espi->clk);
-	if (err)
-		return err;
-
-	val = readl(espi->mmio + SSPCR1);
-	val |= SSPCR1_SSE;
-	writel(val, espi->mmio + SSPCR1);
-
-	return 0;
-}
-
-static void ep93xx_spi_disable(const struct ep93xx_spi *espi)
-{
-	u32 val;
-
-	val = readl(espi->mmio + SSPCR1);
-	val &= ~SSPCR1_SSE;
-	writel(val, espi->mmio + SSPCR1);
-
-	clk_disable(espi->clk);
-}
-
 static void ep93xx_spi_enable_interrupts(const struct ep93xx_spi *espi)
 {
 	u32 val;
@@ -571,17 +544,6 @@ static void ep93xx_spi_process_message(struct ep93xx_spi *espi,
 {
 	unsigned long timeout;
 	struct spi_transfer *t;
-	int err;
-
-	/*
-	 * Enable the SPI controller and its clock.
-	 */
-	err = ep93xx_spi_enable(espi);
-	if (err) {
-		dev_err(&espi->pdev->dev, "failed to enable SPI controller\n");
-		msg->status = err;
-		return;
-	}
 
 	/*
 	 * Just to be sure: flush any data from RX FIFO.
@@ -619,7 +581,6 @@ static void ep93xx_spi_process_message(struct ep93xx_spi *espi,
 	 * deselect the device and disable the SPI controller.
 	 */
 	ep93xx_spi_cs_control(msg->spi, false);
-	ep93xx_spi_disable(espi);
 }
 
 static int ep93xx_spi_transfer_one_message(struct spi_master *master,
@@ -679,6 +640,37 @@ static irqreturn_t ep93xx_spi_interrupt(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+static int ep93xx_spi_prepare_hardware(struct spi_master *master)
+{
+	struct ep93xx_spi *espi = spi_master_get_devdata(master);
+	u32 val;
+	int ret;
+
+	ret = clk_enable(espi->clk);
+	if (ret)
+		return ret;
+
+	val = readl(espi->mmio + SSPCR1);
+	val |= SSPCR1_SSE;
+	writel(val, espi->mmio + SSPCR1);
+
+	return 0;
+}
+
+static int ep93xx_spi_unprepare_hardware(struct spi_master *master)
+{
+	struct ep93xx_spi *espi = spi_master_get_devdata(master);
+	u32 val;
+
+	val = readl(espi->mmio + SSPCR1);
+	val &= ~SSPCR1_SSE;
+	writel(val, espi->mmio + SSPCR1);
+
+	clk_disable(espi->clk);
+
+	return 0;
+}
+
 static bool ep93xx_spi_dma_filter(struct dma_chan *chan, void *filter_param)
 {
 	if (ep93xx_dma_chan_is_m2p(chan))
@@ -780,6 +772,8 @@ static int ep93xx_spi_probe(struct platform_device *pdev)
 	if (!master)
 		return -ENOMEM;
 
+	master->prepare_transfer_hardware = ep93xx_spi_prepare_hardware;
+	master->unprepare_transfer_hardware = ep93xx_spi_unprepare_hardware;
 	master->transfer_one_message = ep93xx_spi_transfer_one_message;
 	master->bus_num = pdev->id;
 	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;