linux-kernel - [PATCH 3/5] i2c-mux-gpio: Save initial channel number to the idle data field

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Message-Id: <20190424123414.25311-4-fancer.lancer@gmail.com>
Date:   Wed, 24 Apr 2019 15:34:12 +0300
From:   Serge Semin <fancer.lancer@...il.com>
To:     Peter Korsgaard <peter.korsgaard@...co.com>,
        Peter Rosin <peda@...ntia.se>
Cc:     Serge Semin <Sergey.Semin@...latforms.ru>,
        linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 3/5] i2c-mux-gpio: Save initial channel number to the idle data field

In case if the idle state has been specified in the data structure,
the idle variable is left untouched as before, so to keep a default
channel number enabled in the mux idle state. But if a platform doesn't
specify which channel is going to be enabled by default, we as before
don't setup the deselect callback, but the initial state is saved in the
idle variable for further initialization. We can safely do this here
since that variable is used for initial state setting only, when no
idling lane is specified.

The reason of this change is to prepare the code for future GPIOs request
path being split up into of- and plat- based methods. The idle variable
here is used as a container of the initial state for both of the paths in
case of idle-channel isn't specified.

Signed-off-by: Serge Semin <fancer.lancer@...il.com>
---
 drivers/i2c/muxes/i2c-mux-gpio.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/i2c/muxes/i2c-mux-gpio.c b/drivers/i2c/muxes/i2c-mux-gpio.c
index a14fe132b0c3..535c83c43371 100644
--- a/drivers/i2c/muxes/i2c-mux-gpio.c
+++ b/drivers/i2c/muxes/i2c-mux-gpio.c
@@ -171,7 +171,6 @@ static int i2c_mux_gpio_probe(struct platform_device *pdev)
 	struct gpiomux *mux;
 	struct i2c_adapter *parent;
 	struct i2c_adapter *root;
-	unsigned initial_state;
 	int i, ret;
 
 	mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
@@ -204,12 +203,14 @@ static int i2c_mux_gpio_probe(struct platform_device *pdev)
 
 	muxc->mux_locked = true;
 
-	if (mux->data.idle != I2C_MUX_GPIO_NO_IDLE) {
-		initial_state = mux->data.idle;
+	/*
+	 * Set descelect callback if idle state has been setup otherwise just
+	 * use the idle variable to store the initial muxer value.
+	 */
+	if (mux->data.idle != I2C_MUX_GPIO_NO_IDLE)
 		muxc->deselect = i2c_mux_gpio_deselect;
-	} else {
-		initial_state = mux->data.values[0];
-	}
+	else
+		mux->data.idle = mux->data.values[0];
 
 	for (i = 0; i < mux->data.n_gpios; i++) {
 		struct device *gpio_dev;
@@ -224,7 +225,7 @@ static int i2c_mux_gpio_probe(struct platform_device *pdev)
 		}
 
 		ret = gpio_direction_output(mux->gpio_base + mux->data.gpios[i],
-					    initial_state & (1 << i));
+					    mux->data.idle & (1 << i));
 		if (ret) {
 			dev_err(&pdev->dev,
 				"Failed to set direction of GPIO %d to output\n",
-- 
2.21.0