Re: [PATCH v3 3/4] mfd: cros_ec: instantiate properly CrOS FP MCU device

From: Benson Leung
Date: Mon Apr 08 2019 - 14:19:17 EST


Hi Enric,

On Mon, Apr 08, 2019 at 11:41:40AM +0200, Enric Balletbo i Serra wrote:
> Support Fingerprint MCU as a special of CrOS EC devices. The current FP
> MCU uses the same EC SPI protocol v3 as other CrOS EC devices on a SPI
> bus.
>
> When a MCU has fingerprint support (aka EC_FEATURE_FINGERPRINT), it is
> instantiated as a special CrOS EC device with device name 'cros_fp'. So
> regardless of the probing order between the actual cros_ec and cros_fp,
> the userspace and other kernel drivers should not confuse them.
>
> Signed-off-by: Vincent Palatin <vpalatin@xxxxxxxxxxxx>
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>

Reviewed-by: Benson Leung <bleung@xxxxxxxxxxxx>

> ---
>
> Changes in v3: None
> Changes in v2: None
>
> drivers/mfd/cros_ec_dev.c | 10 ++++++++++
> include/linux/mfd/cros_ec.h | 1 +
> 2 files changed, 11 insertions(+)
>
> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> index 1daccd4e05a3..79746e817cdb 100644
> --- a/drivers/mfd/cros_ec_dev.c
> +++ b/drivers/mfd/cros_ec_dev.c
> @@ -636,6 +636,16 @@ static int ec_device_probe(struct platform_device *pdev)
> device_initialize(&ec->class_dev);
> cdev_init(&ec->cdev, &fops);
>
> + /* 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.
> diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
> index ce50628aa5e7..b393bd4e4b73 100644
> --- a/include/linux/mfd/cros_ec.h
> +++ b/include/linux/mfd/cros_ec.h
> @@ -23,6 +23,7 @@
> #include <linux/mutex.h>
>
> #define CROS_EC_DEV_NAME "cros_ec"
> +#define CROS_EC_DEV_FP_NAME "cros_fp"
> #define CROS_EC_DEV_ISH_NAME "cros_ish"
> #define CROS_EC_DEV_PD_NAME "cros_pd"
>
> --
> 2.20.1
>

--
Benson Leung
Staff Software Engineer
Chrome OS Kernel
Google Inc.
bleung@xxxxxxxxxx
Chromium OS Project
bleung@xxxxxxxxxxxx

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