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Subject[PATCHv2] mtd: spi-nor: cadence-quadspi: add reset control
Date
Get the reset control for the QSPI controller and bring it out of reset.

Suggested-by: Tien-Fong Chee <tien.fong.chee@intel.com>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
---
v2: use devm_reset_control_get_optional_exclusive
print an error message
return -EPROBE_DEFER
---
drivers/mtd/spi-nor/cadence-quadspi.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/drivers/mtd/spi-nor/cadence-quadspi.c b/drivers/mtd/spi-nor/cadence-quadspi.c
index 792628750eec..c548567adcf0 100644
--- a/drivers/mtd/spi-nor/cadence-quadspi.c
+++ b/drivers/mtd/spi-nor/cadence-quadspi.c
@@ -34,6 +34,7 @@
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
+#include <linux/reset.h>
#include <linux/sched.h>
#include <linux/spi/spi.h>
#include <linux/timer.h>
@@ -1336,6 +1337,7 @@ static int cqspi_probe(struct platform_device *pdev)
struct cqspi_st *cqspi;
struct resource *res;
struct resource *res_ahb;
+ struct reset_control *rstc;
const struct cqspi_driver_platdata *ddata;
int ret;
int irq;
@@ -1362,6 +1364,18 @@ static int cqspi_probe(struct platform_device *pdev)
return PTR_ERR(cqspi->clk);
}

+ /* Obtain QSPI reset control */
+ rstc = devm_reset_control_get_optional_exclusive(dev, NULL);
+ if (IS_ERR(rstc)) {
+ dev_err(dev, "Cannot get QSPI reset.\n");
+ if (PTR_ERR(rstc) == -EPROBE_DEFER)
+ return -EPROBE_DEFER;
+ } else {
+ reset_control_assert(rstc);
+ udelay(1);
+ reset_control_deassert(rstc);
+ }
+
/* Obtain and remap controller address. */
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
cqspi->iobase = devm_ioremap_resource(dev, res);
--
2.20.0
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