From a2f8445d4ca2796283c07d4ba8e78718071de863 Mon Sep 17 00:00:00 2001 From: Mike Looijmans Date: Tue, 1 May 2018 13:42:12 +0200 Subject: i2c: mux: pca954x: force reset on probe if available Instead of just hogging the reset GPIO into deactivated state, activate and then de-activate the reset. This allows for better recovery if the CPU was reset halfway through an I2C transaction for example. Signed-off-by: Mike Looijmans Signed-off-by: Peter Rosin --- drivers/i2c/muxes/i2c-mux-pca954x.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) (limited to 'drivers/i2c/muxes') diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c index 09bafd3e68fa..fe20b8ec5247 100644 --- a/drivers/i2c/muxes/i2c-mux-pca954x.c +++ b/drivers/i2c/muxes/i2c-mux-pca954x.c @@ -36,6 +36,7 @@ */ #include +#include #include #include #include @@ -389,10 +390,16 @@ static int pca954x_probe(struct i2c_client *client, i2c_set_clientdata(client, muxc); data->client = client; - /* Get the mux out of reset if a reset GPIO is specified. */ - gpio = devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_LOW); + /* Reset the mux if a reset GPIO is specified. */ + gpio = devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH); if (IS_ERR(gpio)) return PTR_ERR(gpio); + if (gpio) { + udelay(1); + gpiod_set_value_cansleep(gpio, 0); + /* Give the chip some time to recover. */ + udelay(1); + } match = of_match_device(of_match_ptr(pca954x_of_match), &client->dev); if (match) -- cgit v1.2.3-59-g8ed1b