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Tue, 01 Sep 2026 00:50:04 -0700 (PDT) Received: from wenst-7875.tpe.corp.google.com ([2a00:79e0:201d:8:8cf:6df0:9c4e:f5e1]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2d75988b699sm48142515ad.59.2026.09.01.00.50.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Sep 2026 00:50:04 -0700 (PDT) From: Chen-Yu Tsai To: Mark Brown , Matthias Brugger , AngeloGioacchino Del Regno , Dmitry Torokhov , Jiri Kosina , Andi Shyti Cc: Chen-Yu Tsai , Benson Leung , Tzung-Bi Shih , linux-mediatek@lists.infradead.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, chrome-platform@lists.linux.dev, linux-input@vger.kernel.org, linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v6 4/8] i2c: of-prober: skip post-power-on delay if powered on sufficiently long Date: Tue, 1 Sep 2026 15:49:22 +0800 Message-ID: <20260901074930.764550-5-wenst@chromium.org> X-Mailer: git-send-email 2.55.0.897.gb25b4bd76c-goog In-Reply-To: <20260901074930.764550-1-wenst@chromium.org> References: <20260901074930.764550-1-wenst@chromium.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On some devices the I2C component is powered from an always-on power rail, or the power rail has been left on by either POR defaults or the bootloader. By the time the prober probes the device, the device most certainly has finished initializing and can respond. There is no need for the delay. In such designs, the system integrators tend to work around the delay to avoid the boot time penalty by simply omitting it from the device tree and the component prober. This is undesired, as the device tree is not fully describing the hardware. Switch to the new regulator_enable_and_wait() function that makes sure a certain amount of time has passed since the regulator supply was actually enabled. Signed-off-by: Chen-Yu Tsai --- Changes since v2: - Switched to new regulator_enable_and_wait() API --- drivers/i2c/i2c-core-of-prober.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/i2c/i2c-core-of-prober.c b/drivers/i2c/i2c-core-of-prober.c index 6a82b03809d4..f9f3c0ef93ff 100644 --- a/drivers/i2c/i2c-core-of-prober.c +++ b/drivers/i2c/i2c-core-of-prober.c @@ -18,6 +18,7 @@ #include #include #include +#include /* * Some devices, such as Google Hana Chromebooks, are produced by multiple @@ -226,13 +227,11 @@ static int i2c_of_probe_simple_enable_regulator(struct device *dev, struct i2c_o dev_dbg(dev, "Enabling regulator supply \"%s\"\n", ctx->opts->supply_name); - ret = regulator_enable(ctx->supply); + ret = regulator_enable_and_wait(ctx->supply, + ctx->opts->post_power_on_delay_ms * USEC_PER_MSEC); if (ret) return ret; - if (ctx->opts->post_power_on_delay_ms) - msleep(ctx->opts->post_power_on_delay_ms); - return 0; } -- 2.55.0.897.gb25b4bd76c-goog