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Subject[PATCH v2 2/3] spi: spi-rspi: Add support to deassert/assert reset line
Date
On RZ/G2L SoC we need to explicitly deassert the reset line
for the device to work, use this opportunity to deassert/assert
reset line in spi-rspi driver.

This patch adds support to read the "resets" property (if available)
from DT and perform deassert/assert when required.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
v1->v2
* Included RB tag
---
drivers/spi/spi-rspi.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)

diff --git a/drivers/spi/spi-rspi.c b/drivers/spi/spi-rspi.c
index d16ed88802d3..592682d96562 100644
--- a/drivers/spi/spi-rspi.c
+++ b/drivers/spi/spi-rspi.c
@@ -21,6 +21,7 @@
#include <linux/dma-mapping.h>
#include <linux/of_device.h>
#include <linux/pm_runtime.h>
+#include <linux/reset.h>
#include <linux/sh_dma.h>
#include <linux/spi/spi.h>
#include <linux/spi/rspi.h>
@@ -1225,8 +1226,14 @@ static const struct of_device_id rspi_of_match[] = {

MODULE_DEVICE_TABLE(of, rspi_of_match);

+static void rspi_reset_control_assert(void *data)
+{
+ reset_control_assert(data);
+}
+
static int rspi_parse_dt(struct device *dev, struct spi_controller *ctlr)
{
+ struct reset_control *rstc;
u32 num_cs;
int error;

@@ -1238,6 +1245,24 @@ static int rspi_parse_dt(struct device *dev, struct spi_controller *ctlr)
}

ctlr->num_chipselect = num_cs;
+
+ rstc = devm_reset_control_get_optional_exclusive(dev, NULL);
+ if (IS_ERR(rstc))
+ return dev_err_probe(dev, PTR_ERR(rstc),
+ "failed to get reset ctrl\n");
+
+ error = reset_control_deassert(rstc);
+ if (error) {
+ dev_err(dev, "failed to deassert reset %d\n", error);
+ return error;
+ }
+
+ error = devm_add_action_or_reset(dev, rspi_reset_control_assert, rstc);
+ if (error) {
+ dev_err(dev, "failed to register assert devm action, %d\n", error);
+ return error;
+ }
+
return 0;
}
#else
--
2.17.1
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