Re: [PATCH v3 1/3] i2c: mux: Add i2c-arbitrator-cros-ec 'mux' driver
From: Stephen Warren
Date: Fri Feb 15 2013 - 16:32:00 EST
On 02/15/2013 12:46 PM, Doug Anderson wrote:
> The i2c-arbitrator-cros-ec driver implements the arbitration scheme
> that the Embedded Controller (EC) on the ARM Chromebook expects to use
> for bus multimastering. This i2c-arbitrator-cros-ec driver could also
> be used in other places where standard I2C bus arbitration can't be
> used and two extra GPIOs are available for arbitration.
> This driver is based on code that Simon Glass added to the i2c-s3c2410
> driver in the Chrome OS kernel 3.4 tree. The current incarnation as a
> mux driver is as suggested by Grant Likely. See
> <https://patchwork.kernel.org/patch/1877311/> for some history.
Reviewed-by: Stephen Warren <swarren@xxxxxxxxxx>
> diff --git a/drivers/i2c/muxes/i2c-arbitrator-cros-ec.c b/drivers/i2c/muxes/i2c-arbitrator-cros-ec.c
> +static int i2c_arbitrator_probe(struct platform_device *pdev)
> + /* Request GPIOs */
> + ret = of_get_named_gpio_flags(np, "ap-claim-gpio", 0, &gpio_flags);
> + if (ret == -EPROBE_DEFER || WARN_ON(!gpio_is_valid(ret)))
> + return ret;
I think by the time that doesn't return -EPROBE_DEFER ...
> + arb->ap_gpio = ret;
> + arb->ap_gpio_release = !!(gpio_flags & OF_GPIO_ACTIVE_LOW);
> + out_init = (gpio_flags & OF_GPIO_ACTIVE_LOW) ?
> + GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
> + ret = devm_gpio_request_one(&pdev->dev, arb->ap_gpio, out_init,
> + "ap-claim-gpio");
> + if (ret == -EPROBE_DEFER || WARN_ON(ret))
> + return ret;
... that won't either, since of_get_named_gpio_flags()'s implementation
requires the relevant GPIO driver to be active already.
Still, there's no harm in the code as it stands, so no need to change.
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