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([2a01:e0a:106d:1080:2fb2:cdb7:4ddc:97a6]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-47f85bd77a9sm21222388f8f.14.2026.07.24.01.29.51 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 24 Jul 2026 01:29:51 -0700 (PDT) Message-ID: <646038d3-c4b0-4892-9e8a-29cd498dd317@linaro.org> Date: Fri, 24 Jul 2026 10:29:51 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird From: neil.armstrong@linaro.org Reply-To: Neil Armstrong Subject: Re: [PATCH] regulator: sgm3804: handle gpiod_get_value_cansleep() error returns To: kr494167@gmail.com, broonie@kernel.org, lgirdwood@gmail.com Cc: kancy2333@outlook.com, linux-kernel@vger.kernel.org References: <20260724024625.11057-1-kr494167@gmail.com> Content-Language: en-US, fr Autocrypt: addr=neil.armstrong@linaro.org; keydata= xsBNBE1ZBs8BCAD78xVLsXPwV/2qQx2FaO/7mhWL0Qodw8UcQJnkrWmgTFRobtTWxuRx8WWP GTjuhvbleoQ5Cxjr+v+1ARGCH46MxFP5DwauzPekwJUD5QKZlaw/bURTLmS2id5wWi3lqVH4 BVF2WzvGyyeV1o4RTCYDnZ9VLLylJ9bneEaIs/7cjCEbipGGFlfIML3sfqnIvMAxIMZrvcl9 qPV2k+KQ7q+aXavU5W+yLNn7QtXUB530Zlk/d2ETgzQ5FLYYnUDAaRl+8JUTjc0CNOTpCeik 80TZcE6f8M76Xa6yU8VcNko94Ck7iB4vj70q76P/J7kt98hklrr85/3NU3oti3nrIHmHABEB AAHNKk5laWwgQXJtc3Ryb25nIDxuZWlsLmFybXN0cm9uZ0BsaW5hcm8ub3JnPsLAkQQTAQoA OwIbIwULCQgHAwUVCgkICwUWAgMBAAIeAQIXgBYhBInsPQWERiF0UPIoSBaat7Gkz/iuBQJk Q5wSAhkBAAoJEBaat7Gkz/iuyhMIANiD94qDtUTJRfEW6GwXmtKWwl/mvqQtaTtZID2dos04 YqBbshiJbejgVJjy+HODcNUIKBB3PSLaln4ltdsV73SBcwUNdzebfKspAQunCM22Mn6FBIxQ GizsMLcP/0FX4en9NaKGfK6ZdKK6kN1GR9YffMJd2P08EO8mHowmSRe/ExAODhAs9W7XXExw UNCY4pVJyRPpEhv373vvff60bHxc1k/FF9WaPscMt7hlkbFLUs85kHtQAmr8pV5Hy9ezsSRa GzJmiVclkPc2BY592IGBXRDQ38urXeM4nfhhvqA50b/nAEXc6FzqgXqDkEIwR66/Gbp0t3+r yQzpKRyQif3OwE0ETVkGzwEIALyKDN/OGURaHBVzwjgYq+ZtifvekdrSNl8TIDH8g1xicBYp QTbPn6bbSZbdvfeQPNCcD4/EhXZuhQXMcoJsQQQnO4vwVULmPGgtGf8PVc7dxKOeta+qUh6+ SRh3vIcAUFHDT3f/Zdspz+e2E0hPV2hiSvICLk11qO6cyJE13zeNFoeY3ggrKY+IzbFomIZY 4yG6xI99NIPEVE9lNBXBKIlewIyVlkOaYvJWSV+p5gdJXOvScNN1epm5YHmf9aE2ZjnqZGoM Mtsyw18YoX9BqMFInxqYQQ3j/HpVgTSvmo5ea5qQDDUaCsaTf8UeDcwYOtgI8iL4oHcsGtUX oUk33HEAEQEAAcLAXwQYAQIACQUCTVkGzwIbDAAKCRAWmrexpM/4rrXiB/sGbkQ6itMrAIfn M7IbRuiSZS1unlySUVYu3SD6YBYnNi3G5EpbwfBNuT3H8//rVvtOFK4OD8cRYkxXRQmTvqa3 3eDIHu/zr1HMKErm+2SD6PO9umRef8V82o2oaCLvf4WeIssFjwB0b6a12opuRP7yo3E3gTCS KmbUuLv1CtxKQF+fUV1cVaTPMyT25Od+RC1K+iOR0F54oUJvJeq7fUzbn/KdlhA8XPGzwGRy 4zcsPWvwnXgfe5tk680fEKZVwOZKIEuJC3v+/yZpQzDvGYJvbyix0lHnrCzq43WefRHI5XTT QbM0WUIBIcGmq38+OgUsMYu4NzLu7uZFAcmp6h8g Organization: Linaro In-Reply-To: <20260724024625.11057-1-kr494167@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 7/24/26 04:46, kr494167@gmail.com wrote: > From: Surendra Singh Chouhan > > sgm3804_sync_regcache_state() evaluated !gpiod_get_value_cansleep(...) to > check if the enable GPIOs were down. > > gpiod_get_value_cansleep() returns 1 if active, 0 if inactive, and a > negative error code (e.g. -EIO or -EINVAL) on failure. Evaluating > !gpiod_get_value_cansleep(...) treats a negative error code as boolean > false, swallowing GPIO read failures and misinterpreting a failed read as > an active GPIO. This improperly attempts to sync regcache registers > when the IC may be powered down. > > Fix this by capturing the return values of gpiod_get_value_cansleep() for > both positive and negative rails and propagating any error immediately. > In addition, replace mutex_init() with devm_mutex_init() in probe(). > > Fixes: 0c47e1a8cf5d ("regulator: add SGM3804 Dual Output driver") > Signed-off-by: Surendra Singh Chouhan > --- > drivers/regulator/sgm3804-regulator.c | 17 ++++++++++++++--- > 1 file changed, 14 insertions(+), 3 deletions(-) > > diff --git a/drivers/regulator/sgm3804-regulator.c b/drivers/regulator/sgm3804-regulator.c > index c3406cfb73d0..a430c89b4d5d 100644 > --- a/drivers/regulator/sgm3804-regulator.c > +++ b/drivers/regulator/sgm3804-regulator.c > @@ -97,11 +97,20 @@ static const struct regmap_config sgm3804_regmap_config = { > > static int sgm3804_sync_regcache_state(struct sgm3804_data *ctx) > { > + int pos, neg; > + > guard(mutex)(&ctx->lock); > > + pos = gpiod_get_value_cansleep(ctx->gpios[SGM3804_POS_RAIL]); > + if (pos < 0) > + return pos; > + > + neg = gpiod_get_value_cansleep(ctx->gpios[SGM3804_NEG_RAIL]); > + if (neg < 0) > + return neg; > + > /* If both GPIOs are down, IC is powered down and I2C writes will fail */ > - if (!gpiod_get_value_cansleep(ctx->gpios[SGM3804_POS_RAIL]) && > - !gpiod_get_value_cansleep(ctx->gpios[SGM3804_NEG_RAIL])) { > + if (!pos && !neg) { > regcache_cache_only(ctx->regmap, true); > regcache_mark_dirty(ctx->regmap); > } else { > @@ -235,7 +244,9 @@ static int sgm3804_probe(struct i2c_client *i2c) > if (!ctx) > return -ENOMEM; > > - mutex_init(&ctx->lock); > + ret = devm_mutex_init(dev, &ctx->lock); > + if (ret) > + return ret; > > ctx->regmap = devm_regmap_init_i2c(i2c, &sgm3804_regmap_config); > if (IS_ERR(ctx->regmap)) Reviewed-by: Neil Armstrong Thanks, Neil