[PATCH 2/2] spi: qcom-geni: Add property to force GSI mode

[Pengyu Luo <mitltlatltl@gmail.com>]

Some devices (such as gaokun3) do not disable FIFO mode, causing the
driver to fallback to FIFO mode by default. However, these platforms
also support GSI mode, which is highly preferred for certain
peripherals like SPI touchscreens to improve performance.

Introduce the "qcom,force-gsi-mode" device property to hint and force
the controller into GSI mode during initialization.

Signed-off-by: Pengyu Luo <mitltlatltl@gmail.com>
---
 drivers/spi/spi-geni-qcom.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/spi/spi-geni-qcom.c b/drivers/spi/spi-geni-qcom.c
index 26e723cfea61..eece7312f780 100644
--- a/drivers/spi/spi-geni-qcom.c
+++ b/drivers/spi/spi-geni-qcom.c
@@ -102,6 +102,7 @@ struct spi_geni_master {
 	int irq;
 	bool cs_flag;
 	bool abort_failed;
+	bool force_gsi_mode;
 	struct dma_chan *tx;
 	struct dma_chan *rx;
 	int cur_xfer_mode;
@@ -655,6 +656,9 @@ static int spi_geni_init(struct spi_geni_master *mas)
 		mas->oversampling = 1;
 
 	fifo_disable = readl(se->base + GENI_IF_DISABLE_RO) & FIFO_IF_DISABLE;
+	if (mas->force_gsi_mode)
+		fifo_disable = 1;
+
 	switch (fifo_disable) {
 	case 1:
 		ret = spi_geni_grab_gpi_chan(mas);
@@ -1133,6 +1137,9 @@ static int spi_geni_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	if (device_property_read_bool(&pdev->dev, "qcom,force-gsi-mode"))
+		mas->force_gsi_mode = true;
+
 	ret = spi_geni_init(mas);
 	if (ret)
 		return ret;
-- 
2.54.0