[PATCH] spi: qup: Enable chip select support

[Varadarajan Narayanan]

Enable chip select support for QUP versions later than v1. The
chip select support was broken in QUP version 1. Hence the chip
select support was removed earlier in an earlier commit
(4a8573abe "spi: qup: Remove chip select function"). Since the
chip select support is functional in recent versions of QUP,
re-enabling it for QUP versions later than v1.

Signed-off-by: Sham Muthayyan <smuthayy@xxxxxxxxxxxxxx>
Signed-off-by: Varadarajan Narayanan <varada@xxxxxxxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
---
 drivers/spi/spi-qup.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/spi/spi-qup.c b/drivers/spi/spi-qup.c
index 1bfa889b8427..c0d4defc1c13 100644
--- a/drivers/spi/spi-qup.c
+++ b/drivers/spi/spi-qup.c
@@ -750,6 +750,24 @@ static int spi_qup_init_dma(struct spi_master *master, resource_size_t base)
 	return ret;
 }
 
+static void spi_qup_set_cs(struct spi_device *spi, bool val)
+{
+	struct spi_qup *controller;
+	u32 spi_ioc;
+	u32 spi_ioc_orig;
+
+	controller = spi_master_get_devdata(spi->master);
+	spi_ioc = readl_relaxed(controller->base + SPI_IO_CONTROL);
+	spi_ioc_orig = spi_ioc;
+	if (!val)
+		spi_ioc |= SPI_IO_C_FORCE_CS;
+	else
+		spi_ioc &= ~SPI_IO_C_FORCE_CS;
+
+	if (spi_ioc != spi_ioc_orig)
+		writel_relaxed(spi_ioc, controller->base + SPI_IO_CONTROL);
+}
+
 static int spi_qup_probe(struct platform_device *pdev)
 {
 	struct spi_master *master;
@@ -846,6 +864,9 @@ static int spi_qup_probe(struct platform_device *pdev)
 	if (of_device_is_compatible(dev->of_node, "qcom,spi-qup-v1.1.1"))
 		controller->qup_v1 = 1;
 
+	if (!controller->qup_v1)
+		master->set_cs = spi_qup_set_cs;
+
 	spin_lock_init(&controller->lock);
 	init_completion(&controller->done);
 
-- 
2.13.2