linux-kernel - [PATCH 5.10 067/116] gpio: sifive: use the correct register to read output values

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Date:   Mon, 14 Feb 2022 10:26:06 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Niklas Cassel <niklas.cassel@....com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.10 067/116] gpio: sifive: use the correct register to read output values

From: Niklas Cassel <niklas.cassel@....com>

[ Upstream commit cc38ef936840ac29204d806deb4d1836ec509594 ]

Setting the output of a GPIO to 1 using gpiod_set_value(), followed by
reading the same GPIO using gpiod_get_value(), will currently yield an
incorrect result.

This is because the SiFive GPIO device stores the output values in reg_set,
not reg_dat.

Supply the flag BGPIOF_READ_OUTPUT_REG_SET to bgpio_init() so that the
generic driver reads the correct register.

Fixes: 96868dce644d ("gpio/sifive: Add GPIO driver for SiFive SoCs")
Signed-off-by: Niklas Cassel <niklas.cassel@....com>
Reviewed-by: Linus Walleij <linus.walleij@...aro.org>
[Bartosz: added the Fixes tag]
Signed-off-by: Bartosz Golaszewski <brgl@...ev.pl>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpio/gpio-sifive.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpio/gpio-sifive.c b/drivers/gpio/gpio-sifive.c
index d5eb9ca119016..4f28fa73450c1 100644
--- a/drivers/gpio/gpio-sifive.c
+++ b/drivers/gpio/gpio-sifive.c
@@ -206,7 +206,7 @@ static int sifive_gpio_probe(struct platform_device *pdev)
 			 NULL,
 			 chip->base + SIFIVE_GPIO_OUTPUT_EN,
 			 chip->base + SIFIVE_GPIO_INPUT_EN,
-			 0);
+			 BGPIOF_READ_OUTPUT_REG_SET);
 	if (ret) {
 		dev_err(dev, "unable to init generic GPIO\n");
 		return ret;
-- 
2.34.1