[PATCH 5.10.y-cip 23/27] serial: sh-sci: Add support to deassert/assert reset line


Lad Prabhakar
 

commit 862f72187a41008df2cce3f8e97f57070cbc7060 upstream.

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 sh-sci driver.

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

Also, propagate the error to the caller of sci_parse_dt() instead of
returning NULL in case of failure.

Reviewed-by: Biju Das <biju.das.jz@...>
Reviewed-by: Philipp Zabel <p.zabel@...>
Reviewed-by: Geert Uytterhoeven <geert+renesas@...>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...>
Link: https://lore.kernel.org/r/20211110232920.19198-4-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@...>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...>
---
drivers/tty/serial/sh-sci.c | 39 ++++++++++++++++++++++++++++++-------
1 file changed, 32 insertions(+), 7 deletions(-)

diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index c3fd49480ad3..517aff5f76da 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -37,6 +37,7 @@
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
+#include <linux/reset.h>
#include <linux/scatterlist.h>
#include <linux/serial.h>
#include <linux/serial_sci.h>
@@ -3235,23 +3236,47 @@ static const struct of_device_id of_sci_match[] = {
};
MODULE_DEVICE_TABLE(of, of_sci_match);

+static void sci_reset_control_assert(void *data)
+{
+ reset_control_assert(data);
+}
+
static struct plat_sci_port *sci_parse_dt(struct platform_device *pdev,
unsigned int *dev_id)
{
struct device_node *np = pdev->dev.of_node;
+ struct reset_control *rstc;
struct plat_sci_port *p;
struct sci_port *sp;
const void *data;
- int id;
+ int id, ret;

if (!IS_ENABLED(CONFIG_OF) || !np)
- return NULL;
+ return ERR_PTR(-EINVAL);

data = of_device_get_match_data(&pdev->dev);

+ rstc = devm_reset_control_get_optional_exclusive(&pdev->dev, NULL);
+ if (IS_ERR(rstc))
+ return ERR_PTR(dev_err_probe(&pdev->dev, PTR_ERR(rstc),
+ "failed to get reset ctrl\n"));
+
+ ret = reset_control_deassert(rstc);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to deassert reset %d\n", ret);
+ return ERR_PTR(ret);
+ }
+
+ ret = devm_add_action_or_reset(&pdev->dev, sci_reset_control_assert, rstc);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to register assert devm action, %d\n",
+ ret);
+ return ERR_PTR(ret);
+ }
+
p = devm_kzalloc(&pdev->dev, sizeof(struct plat_sci_port), GFP_KERNEL);
if (!p)
- return NULL;
+ return ERR_PTR(-ENOMEM);

/* Get the line number from the aliases node. */
id = of_alias_get_id(np, "serial");
@@ -3259,11 +3284,11 @@ static struct plat_sci_port *sci_parse_dt(struct platform_device *pdev,
id = ffz(sci_ports_in_use);
if (id < 0) {
dev_err(&pdev->dev, "failed to get alias id (%d)\n", id);
- return NULL;
+ return ERR_PTR(-EINVAL);
}
if (id >= ARRAY_SIZE(sci_ports)) {
dev_err(&pdev->dev, "serial%d out of range\n", id);
- return NULL;
+ return ERR_PTR(-EINVAL);
}

sp = &sci_ports[id];
@@ -3350,8 +3375,8 @@ static int sci_probe(struct platform_device *dev)

if (dev->dev.of_node) {
p = sci_parse_dt(dev, &dev_id);
- if (p == NULL)
- return -EINVAL;
+ if (IS_ERR(p))
+ return PTR_ERR(p);
} else {
p = dev->dev.platform_data;
if (p == NULL) {
--
2.17.1

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