From a60d57586f5d5c7dbf7e0bd94cf7bf5f3b91c293 Mon Sep 17 00:00:00 2001 From: Andrey Gusakov Date: Wed, 13 Jun 2018 14:06:59 +0300 Subject: [PATCH 114/115] i2c: mux: pca954x: reset mux in case of error during bus deselect Also reset device on probe to workaround reset errata at low supply rise rate. Signed-off-by: Andrey Gusakov --- drivers/i2c/muxes/i2c-mux-pca954x.c | 29 ++++++++++++++++++++++++----- 1 file changed, 24 insertions(+), 5 deletions(-) diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c index 7b992db..b26d6a0 100644 --- a/drivers/i2c/muxes/i2c-mux-pca954x.c +++ b/drivers/i2c/muxes/i2c-mux-pca954x.c @@ -35,6 +35,7 @@ * warranty of any kind, whether express or implied. */ +#include #include #include #include @@ -78,6 +79,7 @@ struct chip_desc { struct pca954x { const struct chip_desc *chip; + struct gpio_desc *gpio; /* reset gpio */ u8 last_chan; /* last register value */ u8 deselect; struct i2c_client *client; @@ -217,13 +219,24 @@ static int pca954x_deselect_mux(struct i2c_mux_core *muxc, u32 chan) { struct pca954x *data = i2c_mux_priv(muxc); struct i2c_client *client = data->client; + int ret; if (!(data->deselect & (1 << chan))) return 0; /* Deselect active channel */ data->last_chan = 0; - return pca954x_reg_write(muxc->parent, client, data->last_chan); + ret = pca954x_reg_write(muxc->parent, client, data->last_chan); + if ((ret < 0) && (data->gpio)) { + gpiod_set_value(data->gpio, GPIOD_OUT_HIGH); + udelay(5); + gpiod_set_value(data->gpio, GPIOD_OUT_LOW); + /* retry */ + ret = pca954x_reg_write(muxc->parent, client, data->last_chan); + if (ret < 0) + dev_err(&data->client->dev, "error deselecting channed %d: %d\n", chan, ret); + } + return ret; } static irqreturn_t pca954x_irq_handler(int irq, void *dev_id) @@ -344,7 +357,6 @@ static int pca954x_probe(struct i2c_client *client, struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev); struct device_node *of_node = client->dev.of_node; bool idle_disconnect_dt; - struct gpio_desc *gpio; int num, force, class; struct i2c_mux_core *muxc; struct pca954x *data; @@ -365,9 +377,16 @@ static int pca954x_probe(struct i2c_client *client, 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); - if (IS_ERR(gpio)) - return PTR_ERR(gpio); + data->gpio = devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH); + if (IS_ERR(data->gpio)) + return PTR_ERR(data->gpio); + + if (data->gpio) { + /* delay and release reset */ + udelay(1); + gpiod_set_value(data->gpio, 0); + udelay(1); + } /* Write the mux register at addr to verify * that the mux is in fact present. This also -- 1.9.1