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From: Thomas Richard <thomas.richard@bootlin.com>
Date: Fri, 26 Jan 2024 15:36:46 +0100
Subject: [PATCH v2 04/15] mux: add mux_chip_resume() function
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To: Linus Walleij <linus.walleij@linaro.org>, 
 Bartosz Golaszewski <brgl@bgdev.pl>, Andy Shevchenko <andy@kernel.org>, 
 Tony Lindgren <tony@atomide.com>, 
 Haojian Zhuang <haojian.zhuang@linaro.org>, Vignesh R <vigneshr@ti.com>, 
 Aaro Koskinen <aaro.koskinen@iki.fi>, 
 Janusz Krzysztofik <jmkrzyszt@gmail.com>, 
 Andi Shyti <andi.shyti@kernel.org>, Peter Rosin <peda@axentia.se>, 
 Vinod Koul <vkoul@kernel.org>, Kishon Vijay Abraham I <kishon@kernel.org>, 
 Philipp Zabel <p.zabel@pengutronix.de>, Tom Joseph <tjoseph@cadence.com>, 
 Lorenzo Pieralisi <lpieralisi@kernel.org>, 
 =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= <kw@linux.com>, 
 Rob Herring <robh@kernel.org>, Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, 
 linux-arm-kernel@lists.infradead.org, linux-omap@vger.kernel.org, 
 linux-i2c@vger.kernel.org, linux-phy@lists.infradead.org, 
 linux-pci@vger.kernel.org, gregory.clement@bootlin.com, 
 theo.lebrun@bootlin.com, thomas.petazzoni@bootlin.com, u-kumar1@ti.com, 
 Thomas Richard <thomas.richard@bootlin.com>

The mux_chip_resume() function restores a mux_chip using the cached state
of each mux.

Signed-off-by: Thomas Richard <thomas.richard@bootlin.com>
---
 drivers/mux/core.c         | 27 +++++++++++++++++++++++++++
 include/linux/mux/driver.h |  1 +
 2 files changed, 28 insertions(+)

diff --git a/drivers/mux/core.c b/drivers/mux/core.c
index 775816112932..896f74b34eb8 100644
--- a/drivers/mux/core.c
+++ b/drivers/mux/core.c
@@ -215,6 +215,33 @@ void mux_chip_free(struct mux_chip *mux_chip)
 }
 EXPORT_SYMBOL_GPL(mux_chip_free);
 
+/**
+ * mux_chip_resume() - restores the mux-chip state
+ * @mux_chip: The mux-chip to resume.
+ *
+ * Restores the mux-chip state.
+ *
+ * Return: Zero on success or a negative errno on error.
+ */
+int mux_chip_resume(struct mux_chip *mux_chip)
+{
+	int ret, i;
+
+	for (i = 0; i < mux_chip->controllers; ++i) {
+		struct mux_control *mux = &mux_chip->mux[i];
+
+		if (mux->cached_state != MUX_CACHE_UNKNOWN) {
+			ret = mux_control_set(mux, mux->cached_state);
+			if (ret < 0) {
+				dev_err(&mux_chip->dev, "unable to restore state\n");
+				return ret;
+			}
+		}
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mux_chip_resume);
+
 static void devm_mux_chip_release(struct device *dev, void *res)
 {
 	struct mux_chip *mux_chip = *(struct mux_chip **)res;
diff --git a/include/linux/mux/driver.h b/include/linux/mux/driver.h
index 18824064f8c0..2a7e5ec5d540 100644
--- a/include/linux/mux/driver.h
+++ b/include/linux/mux/driver.h
@@ -88,6 +88,7 @@ struct mux_chip *mux_chip_alloc(struct device *dev,
 int mux_chip_register(struct mux_chip *mux_chip);
 void mux_chip_unregister(struct mux_chip *mux_chip);
 void mux_chip_free(struct mux_chip *mux_chip);
+int mux_chip_resume(struct mux_chip *mux_chip);
 
 struct mux_chip *devm_mux_chip_alloc(struct device *dev,
 				     unsigned int controllers,

-- 
2.39.2