i2c: gpio: flag atomic capability if possible

If switching GPIOs does not sleep, then we can support atomic transfers.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/i2c-gpio.c

@@ -413,6 +413,8 @@ static int i2c_gpio_probe(struct platform_device *pdev)
 
 	if (gpiod_cansleep(priv->sda) || gpiod_cansleep(priv->scl))
 		dev_warn(dev, "Slow GPIO pins might wreak havoc into I2C/SMBus bus timing");
+	else
+		bit_data->can_do_atomic = true;
 
 	bit_data->setsda = i2c_gpio_setsda_val;
 	bit_data->setscl = i2c_gpio_setscl_val;