linux-kernel - Re: [PATCH v4 5/8] mfd: cros_ec_dev: Register cros_ec_accel

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Message-ID: <20180328110330.y4pq5mhm73jfq6j6@dell>
Date:   Wed, 28 Mar 2018 12:03:30 +0100
From:   Lee Jones <lee.jones@...aro.org>
To:     Enric Balletbo i Serra <enric.balletbo@...labora.com>
Cc:     groeck@...omium.org, andy.shevchenko@...il.com,
        kernel@...labora.com, gwendal@...omium.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 5/8] mfd: cros_ec_dev: Register cros_ec_accel_legacy
 driver as a subdevice.

On Tue, 20 Mar 2018, Enric Balletbo i Serra wrote:

> With this patch, the cros_ec_ctl driver will register the legacy
> accelerometer driver (named cros_ec_accel_legacy) if it fails to
> register sensors through the usual path cros_ec_sensors_register().
> This legacy device is present on Chromebook devices with older EC
> firmware only supporting deprecated EC commands (Glimmer based devices).
> 
> Tested-by: Gwendal Grignou <gwendal@...omium.org>
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@...labora.com>
> Reviewed-by: Gwendal Grignou <gwendal@...omium.org>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>
> ---
> 
> Changes in v4:
> - [5/8] Nit: EC -> ECs (Lee Jones)
> - [5/8] Statically define cros_ec_accel_legacy_cells (Lee Jones)
> 
> Changes in v3:
> - [5/8] Add the Reviewed-by Andy Shevchenko.
> 
> Changes in v2:
> - [5/8] Add the Reviewed-by Gwendal.
> 
>  drivers/mfd/cros_ec_dev.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 70 insertions(+)
> 
> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> index f60a53f11942..0d541d59d6f5 100644
> --- a/drivers/mfd/cros_ec_dev.c
> +++ b/drivers/mfd/cros_ec_dev.c
> @@ -389,6 +389,73 @@ static void cros_ec_sensors_register(struct cros_ec_dev *ec)
>  	kfree(msg);
>  }
>  
> +static struct cros_ec_sensor_platform sensor_platforms[] = {
> +	{
> +		.sensor_num = 0,
> +	},
> +	{
> +		.sensor_num = 1,
> +	}
> +};

Also no need to be so many  lines.

Each one of these entries can be placed on a single line.

And there's no need for a comma if there is nothing to separate.

	{ .sensor_num = 0 },
	{ .sensor_num = 1 }

Also, this seems like a pretty pointless struct.

What is the sensor_num property used for?

Why does it care what sensor number it is?

> +static const struct mfd_cell cros_ec_accel_legacy_cells[] = {
> +	{
> +		.name = "cros-ec-accel-legacy",
> +		.id = 0,

What are you using this for?

> +		.platform_data = &sensor_platforms[0],
> +		.pdata_size = sizeof(struct cros_ec_sensor_platform),
> +	},
> +	{
> +		.name = "cros-ec-accel-legacy",
> +		.id = 1,

And this?

> +		.platform_data = &sensor_platforms[1],
> +		.pdata_size = sizeof(struct cros_ec_sensor_platform),
> +	}
> +};
> +
> +static void cros_ec_accel_legacy_register(struct cros_ec_dev *ec)
> +{
> +	struct cros_ec_device *ec_dev = ec->ec_dev;
> +	u8 status;
> +	int ret;
> +
> +	/*
> +	 * ECs that need legacy support are the main EC, directly connected to
> +	 * the AP.
> +	 */
> +	if (ec->cmd_offset != 0)
> +		return;
> +
> +	/*
> +	 * Check if EC supports direct memory reads and if EC has
> +	 * accelerometers.
> +	 */
> +	if (!ec_dev->cmd_readmem)
> +		return;
> +
> +	ret = ec_dev->cmd_readmem(ec_dev, EC_MEMMAP_ACC_STATUS, 1, &status);
> +	if (ret < 0) {
> +		dev_warn(ec->dev, "EC does not support direct reads.\n");
> +		return;
> +	}
> +
> +	/* Check if EC has accelerometers. */
> +	if (!(status & EC_MEMMAP_ACC_STATUS_PRESENCE_BIT)) {
> +		dev_info(ec->dev, "EC does not have accelerometers.\n");
> +		return;
> +	}
> +
> +	/*
> +	 * Register 2 accelerometers
> +	 */
> +	ret = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
> +			      cros_ec_accel_legacy_cells,
> +			      ARRAY_SIZE(cros_ec_accel_legacy_cells),
> +			      NULL, 0, NULL);
> +	if (ret)
> +		dev_err(ec_dev->dev, "failed to add EC sensors\n");
> +}
> +
>  static const struct mfd_cell cros_ec_rtc_cells[] = {
>  	{
>  		.name = "cros-ec-rtc",
> @@ -442,6 +509,9 @@ static int ec_device_probe(struct platform_device *pdev)
>  	/* check whether this EC is a sensor hub. */
>  	if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE))
>  		cros_ec_sensors_register(ec);
> +	else
> +		/* Workaroud for older EC firmware */
> +		cros_ec_accel_legacy_register(ec);
>  
>  	/* Check whether this EC instance has RTC host command support */
>  	if (cros_ec_check_features(ec, EC_FEATURE_RTC)) {

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