Merge tag 'spi-v3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi

Pull spi updates from Mark Brown:
 "A quiet release, more bug fixes than anything else.  A few things do
  stand out though:

   - updates to several drivers to move towards the standard GPIO chip
     select handling in the core.
   - DMA support for the SH MSIOF driver.
   - support for Rockchip SPI controllers (their first mainline
     submission)"

* tag 'spi-v3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi: (64 commits)
  spi: davinci: use spi_device.cs_gpio to store gpio cs per spi device
  spi: davinci: add support to configure gpio cs through dt
  spi/pl022: Explicitly truncate large bitmask
  spi/atmel: Fix pointer to int conversion warnings on 64 bit builds
  spi: davinci: fix to support more than 2 chip selects
  spi: topcliff-pch: don't hardcode PCI slot to get DMA device
  spi: orion: fix incorrect handling of cell-index DT property
  spi: orion: Fix error return code in orion_spi_probe()
  spi/rockchip: fix error return code in rockchip_spi_probe()
  spi/rockchip: remove redundant dev_err call in rockchip_spi_probe()
  spi/rockchip: remove duplicated include from spi-rockchip.c
  ARM: dts: fix the chip select gpios definition in the SPI nodes
  spi: s3c64xx: Update binding documentation
  spi: s3c64xx: use the generic SPI "cs-gpios" property
  spi: s3c64xx: Revert "spi: s3c64xx: Added provision for dedicated cs pin"
  spi: atmel: Use dmaengine_prep_slave_sg() API
  spi: topcliff-pch: Update error messages for dmaengine_prep_slave_sg() API
  spi: sh-msiof: Use correct device for DMA mapping with IOMMU
  spi: sh-msiof: Handle dmaengine_prep_slave_single() failures gracefully
  spi: rspi: Handle dmaengine_prep_slave_sg() failures gracefully
  ...

1 files changed, 27 insertions, 10 deletions

diff --git a/drivers/spi/spi-cadence.c b/drivers/spi/spi-cadence.c
index bb75897..562ff83 100644
--- a/drivers/spi/spi-cadence.c
+++ b/drivers/spi/spi-cadence.c
@@ -205,18 +205,30 @@ static void cdns_spi_chipselect(struct spi_device *spi, bool is_high)
 static void cdns_spi_config_clock_mode(struct spi_device *spi)
 {
 	struct cdns_spi *xspi = spi_master_get_devdata(spi->master);
-	u32 ctrl_reg;
+	u32 ctrl_reg, new_ctrl_reg;
 
-	ctrl_reg = cdns_spi_read(xspi, CDNS_SPI_CR_OFFSET);
+	new_ctrl_reg = ctrl_reg = cdns_spi_read(xspi, CDNS_SPI_CR_OFFSET);
 
 	/* Set the SPI clock phase and clock polarity */
-	ctrl_reg &= ~(CDNS_SPI_CR_CPHA_MASK | CDNS_SPI_CR_CPOL_MASK);
+	new_ctrl_reg &= ~(CDNS_SPI_CR_CPHA_MASK | CDNS_SPI_CR_CPOL_MASK);
 	if (spi->mode & SPI_CPHA)
-		ctrl_reg |= CDNS_SPI_CR_CPHA_MASK;
+		new_ctrl_reg |= CDNS_SPI_CR_CPHA_MASK;
 	if (spi->mode & SPI_CPOL)
-		ctrl_reg |= CDNS_SPI_CR_CPOL_MASK;
-
-	cdns_spi_write(xspi, CDNS_SPI_CR_OFFSET, ctrl_reg);
+		new_ctrl_reg |= CDNS_SPI_CR_CPOL_MASK;
+
+	if (new_ctrl_reg != ctrl_reg) {
+		/*
+		 * Just writing the CR register does not seem to apply the clock
+		 * setting changes. This is problematic when changing the clock
+		 * polarity as it will cause the SPI slave to see spurious clock
+		 * transitions. To workaround the issue toggle the ER register.
+		 */
+		cdns_spi_write(xspi, CDNS_SPI_ER_OFFSET,
+				   CDNS_SPI_ER_DISABLE_MASK);
+		cdns_spi_write(xspi, CDNS_SPI_CR_OFFSET, new_ctrl_reg);
+		cdns_spi_write(xspi, CDNS_SPI_ER_OFFSET,
+				   CDNS_SPI_ER_ENABLE_MASK);
+	}
 }
 
 /**
@@ -370,6 +382,12 @@ static irqreturn_t cdns_spi_irq(int irq, void *dev_id)
 
 	return status;
 }
+static int cdns_prepare_message(struct spi_master *master,
+				struct spi_message *msg)
+{
+	cdns_spi_config_clock_mode(msg->spi);
+	return 0;
+}
 
 /**
  * cdns_transfer_one - Initiates the SPI transfer
@@ -416,8 +434,6 @@ static int cdns_prepare_transfer_hardware(struct spi_master *master)
 {
 	struct cdns_spi *xspi = spi_master_get_devdata(master);
 
-	cdns_spi_config_clock_mode(master->cur_msg->spi);
-
 	cdns_spi_write(xspi, CDNS_SPI_ER_OFFSET,
 		       CDNS_SPI_ER_ENABLE_MASK);
 
@@ -532,6 +548,7 @@ static int cdns_spi_probe(struct platform_device *pdev)
 		xspi->is_decoded_cs = 0;
 
 	master->prepare_transfer_hardware = cdns_prepare_transfer_hardware;
+	master->prepare_message = cdns_prepare_message;
 	master->transfer_one = cdns_transfer_one;
 	master->unprepare_transfer_hardware = cdns_unprepare_transfer_hardware;
 	master->set_cs = cdns_spi_chipselect;
@@ -647,7 +664,7 @@ static int __maybe_unused cdns_spi_resume(struct device *dev)
 static SIMPLE_DEV_PM_OPS(cdns_spi_dev_pm_ops, cdns_spi_suspend,
 			 cdns_spi_resume);
 
-static struct of_device_id cdns_spi_of_match[] = {
+static const struct of_device_id cdns_spi_of_match[] = {
 	{ .compatible = "xlnx,zynq-spi-r1p6" },
 	{ .compatible = "cdns,spi-r1p6" },
 	{ /* end of table */ }