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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Chen-Yu Tsai <wenst@chromium.org>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 419/599] pinctrl: mediatek: paris: Fix PIN_CONFIG_BIAS_* readback
Date:   Tue,  5 Apr 2022 09:31:53 +0200
Message-Id: <20220405070311.301666980@linuxfoundation.org>
In-Reply-To: <20220405070258.802373272@linuxfoundation.org>
References: <20220405070258.802373272@linuxfoundation.org>
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From: Chen-Yu Tsai <wenst@chromium.org>

[ Upstream commit 3e8c6bc608480010f360c4a59578d7841726137d ]

When reading back pin bias settings, if the pin is not in the
corresponding bias state, the function should return -EINVAL.

Fix this in the mediatek-paris pinctrl library so that the read back
state is not littered with bogus a "input bias disabled" combined with
"pull up" or "pull down" states.

Fixes: 805250982bb5 ("pinctrl: mediatek: add pinctrl-paris that implements the vendor dt-bindings")
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20220308100956.2750295-3-wenst@chromium.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/pinctrl/mediatek/pinctrl-paris.c | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/drivers/pinctrl/mediatek/pinctrl-paris.c b/drivers/pinctrl/mediatek/pinctrl-paris.c
index 623af4410b07..4dd5bd2f135e 100644
--- a/drivers/pinctrl/mediatek/pinctrl-paris.c
+++ b/drivers/pinctrl/mediatek/pinctrl-paris.c
@@ -96,20 +96,16 @@ static int mtk_pinconf_get(struct pinctrl_dev *pctldev,
 			err = hw->soc->bias_get_combo(hw, desc, &pullup, &ret);
 			if (err)
 				goto out;
+			if (ret == MTK_PUPD_SET_R1R0_00)
+				ret = MTK_DISABLE;
 			if (param == PIN_CONFIG_BIAS_DISABLE) {
-				if (ret == MTK_PUPD_SET_R1R0_00)
-					ret = MTK_DISABLE;
+				if (ret != MTK_DISABLE)
+					err = -EINVAL;
 			} else if (param == PIN_CONFIG_BIAS_PULL_UP) {
-				/* When desire to get pull-up value, return
-				 *  error if current setting is pull-down
-				 */
-				if (!pullup)
+				if (!pullup || ret == MTK_DISABLE)
 					err = -EINVAL;
 			} else if (param == PIN_CONFIG_BIAS_PULL_DOWN) {
-				/* When desire to get pull-down value, return
-				 *  error if current setting is pull-up
-				 */
-				if (pullup)
+				if (pullup || ret == MTK_DISABLE)
 					err = -EINVAL;
 			}
 		} else {
-- 
2.34.1