spi: spi-rspi: Add support to deassert/assert reset line

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>
Link: https://lore.kernel.org/r/20211118031041.2312-3-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Lad Prabhakar 2021-11-18 03:10:40 +00:00 committed by Mark Brown
parent 5a8f8542e3
commit aadbff4af5
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@ -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