Re: [PATCH v5 08/11] mfd: cros_ec: Add convenience struct to define dedicated CrOS EC MCUs

[Lee Jones <lee.jones@linaro.org>]

On Mon, 22 Jul 2019, Enric Balletbo i Serra wrote:

> With the increasing use of dedicated CrOS EC MCUs, it takes a fair amount
> of boiler plate code to add those devices, add a struct that can be used
> to specify a dedicated CrOS EC MCU so we can just add a new item to it to
> define a new dedicated MCU.
> 
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Reviewed-by: Gwendal Grignou <gwendal@chromium.org>
> Tested-by: Gwendal Grignou <gwendal@chromium.org>
> ---
> 
> Changes in v5: None
> Changes in v4: None
> Changes in v3: None
> Changes in v2: None
> 
>  drivers/mfd/cros_ec_dev.c | 87 +++++++++++++++++++++------------------
>  1 file changed, 48 insertions(+), 39 deletions(-)
> 
> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> index c6bf52d795f2..e0e18c0eb9f5 100644
> --- a/drivers/mfd/cros_ec_dev.c
> +++ b/drivers/mfd/cros_ec_dev.c
> @@ -22,6 +22,41 @@ static struct class cros_class = {
>  	.name           = "chromeos",
>  };
>  
> +/**
> + * cros_feature_to_name - CrOS feature id to name/short description.
> + * @id: The feature identifier.
> + * @name: Device name associated with the feature id.
> + * @desc: Short name that will be displayed.
> + */
> +struct cros_feature_to_name {
> +	unsigned int id;
> +	const char *name;
> +	const char *desc;
> +};
> +
> +static const struct cros_feature_to_name cros_mcu_devices[] = {
> +	{
> +		.id	= EC_FEATURE_FINGERPRINT,
> +		.name	= CROS_EC_DEV_FP_NAME,
> +		.desc	= "Fingerprint",
> +	},
> +	{
> +		.id	= EC_FEATURE_ISH,
> +		.name	= CROS_EC_DEV_ISH_NAME,
> +		.desc	= "Integrated Sensor Hub",
> +	},
> +	{
> +		.id	= EC_FEATURE_SCP,
> +		.name	= CROS_EC_DEV_SCP_NAME,
> +		.desc	= "System Control Processor",
> +	},
> +	{
> +		.id	= EC_FEATURE_TOUCHPAD,
> +		.name	= CROS_EC_DEV_TP_NAME,
> +		.desc	= "Touchpad",
> +	},
> +};
> +
>  static int cros_ec_check_features(struct cros_ec_dev *ec, int feature)
>  {
>  	struct cros_ec_command *msg;
> @@ -278,6 +313,7 @@ static int ec_device_probe(struct platform_device *pdev)
>  	struct device *dev = &pdev->dev;
>  	struct cros_ec_platform *ec_platform = dev_get_platdata(dev);
>  	struct cros_ec_dev *ec = kzalloc(sizeof(*ec), GFP_KERNEL);
> +	int i;
>  
>  	if (!ec)
>  		return retval;
> @@ -290,47 +326,20 @@ static int ec_device_probe(struct platform_device *pdev)
>  	ec->features[1] = -1U; /* Not cached yet */
>  	device_initialize(&ec->class_dev);
>  
> -	/* Check whether this is actually a Fingerprint MCU rather than an EC */
> -	if (cros_ec_check_features(ec, EC_FEATURE_FINGERPRINT)) {
> -		dev_info(dev, "CrOS Fingerprint MCU detected.\n");
> -		/*
> -		 * Help userspace differentiating ECs from FP MCU,
> -		 * regardless of the probing order.
> -		 */
> -		ec_platform->ec_name = CROS_EC_DEV_FP_NAME;
> -	}
> -
> -	/*
> -	 * Check whether this is actually an Integrated Sensor Hub (ISH)
> -	 * rather than an EC.
> -	 */
> -	if (cros_ec_check_features(ec, EC_FEATURE_ISH)) {
> -		dev_info(dev, "CrOS ISH MCU detected.\n");
> -		/*
> -		 * Help userspace differentiating ECs from ISH MCU,
> -		 * regardless of the probing order.
> -		 */
> -		ec_platform->ec_name = CROS_EC_DEV_ISH_NAME;
> -	}
> -
> -	/* Check whether this is actually a Touchpad MCU rather than an EC */
> -	if (cros_ec_check_features(ec, EC_FEATURE_TOUCHPAD)) {
> -		dev_info(dev, "CrOS Touchpad MCU detected.\n");
> +	for (i = 0; i < ARRAY_SIZE(cros_mcu_devices); i++) {
>  		/*
> -		 * Help userspace differentiating ECs from TP MCU,
> -		 * regardless of the probing order.
> +		 * Check whether this is actually a dedicated MCU rather
> +		 * than an standard EC.
>  		 */
> -		ec_platform->ec_name = CROS_EC_DEV_TP_NAME;
> -	}
> -
> -	/* Check whether this is actually a SCP rather than an EC. */
> -	if (cros_ec_check_features(ec, EC_FEATURE_SCP)) {
> -		dev_info(dev, "CrOS SCP MCU detected.\n");
> -		/*
> -		 * Help userspace differentiating ECs from SCP,
> -		 * regardless of the probing order.
> -		 */
> -		ec_platform->ec_name = CROS_EC_DEV_SCP_NAME;
> +		if (cros_ec_check_features(ec, cros_mcu_devices[i].id)) {
> +			dev_info(dev, "CrOS %s MCU detected\n",
> +				 cros_mcu_devices[i].desc);
> +			/*
> +			 * Help userspace differentiating ECs from other MCU,
> +			 * regardless of the probing order.
> +			 */
> +			ec_platform->ec_name = cros_mcu_devices[i].name;

I assume by "dedicated MCU", you mean it can only support one of these
at a time?  If so, please make that clear by adding a break statement
once the MCU type has been determined.

> +		}
>  	}
>  
>  	/*

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
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