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serial: sh-sci: Add support to deassert/assert reset line

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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@bp.renesas.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20211110232920.19198-4-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Lad Prabhakar 2021-11-10 23:29:20 +00:00 committed by Greg Kroah-Hartman
parent e1c0fc1013
commit 862f72187a
1 changed files with 32 additions and 7 deletions
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39
drivers/tty/serial/sh-sci.c
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@ -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>
@ -3203,23 +3204,47 @@ 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");
@ -3227,11 +3252,11 @@ 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];
@ -3318,8 +3343,8 @@ 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) {