[PATCH 2/2] spi: cadence-quadspi: fix suspend-resume implementations

[Dhruva Gole <d-gole@ti.com>]

The cadence QSPI driver misbehaves after performing a full system suspend
resume:
...
spi-nor spi0.0: resume() failed
...
This results in a flash connected via OSPI interface after system suspend-
resume to be unusable.
fix these suspend and resume functions.

Fixes: 140623410536 ("mtd: spi-nor: Add driver for Cadence Quad SPI Flash Controller")
Signed-off-by: Dhruva Gole <d-gole@ti.com>
---
 drivers/spi/spi-cadence-quadspi.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi-cadence-quadspi.c b/drivers/spi/spi-cadence-quadspi.c
index d47e954fe809..91908e8cf92e 100644
--- a/drivers/spi/spi-cadence-quadspi.c
+++ b/drivers/spi/spi-cadence-quadspi.c
@@ -1816,17 +1816,30 @@ static void cqspi_remove(struct platform_device *pdev)
 static int cqspi_suspend(struct device *dev)
 {
 	struct cqspi_st *cqspi = dev_get_drvdata(dev);
+	struct spi_master *master = dev_get_drvdata(dev);
+	int ret;
 
+	ret = spi_master_suspend(master);
 	cqspi_controller_enable(cqspi, 0);
-	return 0;
+
+	clk_disable_unprepare(cqspi->clk);
+
+	return ret;
 }
 
 static int cqspi_resume(struct device *dev)
 {
 	struct cqspi_st *cqspi = dev_get_drvdata(dev);
+	struct spi_master *master = dev_get_drvdata(dev);
 
-	cqspi_controller_enable(cqspi, 1);
-	return 0;
+	clk_prepare_enable(cqspi->clk);
+	cqspi_wait_idle(cqspi);
+	cqspi_controller_init(cqspi);
+
+	cqspi->current_cs = -1;
+	cqspi->sclk = 0;
+
+	return spi_master_resume(master);
 }
 
 static SIMPLE_DEV_PM_OPS(cqspi__dev_pm_ops, cqspi_suspend, cqspi_resume);
-- 
2.25.1