[stable-kernel][5.15.y][PATCH 3/5] serial: sc16is7xx: remove global regmap from struct sc16is7xx_port

[Hui Wang <hui.wang@canonical.com>]

From: Hugo Villeneuve <hvilleneuve@dimonoff.com>

commit f6959c5217bd799bcb770b95d3c09b3244e175c6 upstream.

Remove global struct regmap so that it is more obvious that this
regmap is to be used only in the probe function.

Also add a comment to that effect in probe function.

[Hui: fixed some conflict when backporting to 5.15.y]

Fixes: 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port")
Cc:  <stable@vger.kernel.org>
Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20231211171353.2901416-3-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Hui Wang <hui.wang@canonical.com>
---
 drivers/tty/serial/sc16is7xx.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 35001cc7ec90..90b39ddec082 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -323,7 +323,6 @@ struct sc16is7xx_one {
 
 struct sc16is7xx_port {
 	const struct sc16is7xx_devtype	*devtype;
-	struct regmap			*regmap;
 	struct clk			*clk;
 #ifdef CONFIG_GPIOLIB
 	struct gpio_chip		gpio;
@@ -1222,6 +1221,10 @@ static int sc16is7xx_probe(struct device *dev,
 	 * This device does not have an identification register that would
 	 * tell us if we are really connected to the correct device.
 	 * The best we can do is to check if communication is at all possible.
+	 *
+	 * Note: regmap[0] is used in the probe function to access registers
+	 * common to all channels/ports, as it is guaranteed to be present on
+	 * all variants.
 	 */
 	ret = regmap_read(regmaps[0], SC16IS7XX_LSR_REG, &val);
 	if (ret < 0)
@@ -1257,7 +1260,6 @@ static int sc16is7xx_probe(struct device *dev,
 			return -EINVAL;
 	}
 
-	s->regmap = regmaps[0];
 	s->devtype = devtype;
 	dev_set_drvdata(dev, s);
 	mutex_init(&s->efr_lock);
@@ -1272,7 +1274,7 @@ static int sc16is7xx_probe(struct device *dev,
 	sched_set_fifo(s->kworker_task);
 
 	/* reset device, purging any pending irq / data */
-	regmap_write(s->regmap, SC16IS7XX_IOCONTROL_REG,
+	regmap_write(regmaps[0], SC16IS7XX_IOCONTROL_REG,
 		     SC16IS7XX_IOCONTROL_SRESET_BIT);
 
 	for (i = 0; i < devtype->nr_uart; ++i) {
-- 
2.34.1