Commit 862f7218 authored by Lad Prabhakar's avatar Lad Prabhakar Committed by Greg Kroah-Hartman
Browse files

serial: sh-sci: 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 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: default avatarBiju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: default avatarPhilipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: default avatarLad 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: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent e1c0fc10

drivers/tty/serial/sh-sci.c

+32 −7
Original line number Diff line number Diff line
@@ -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) {