linux-kernel - Re: [PATCH v2 7/9] iio: imu: adis: add support product ID check in adis_initial

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Date:   Fri, 14 Feb 2020 14:41:21 +0000
From:   Jonathan Cameron <jic23@...nel.org>
To:     Alexandru Ardelean <alexandru.ardelean@...log.com>
Cc:     <linux-iio@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <nuno.sa@...log.com>
Subject: Re: [PATCH v2 7/9] iio: imu: adis: add support product ID check in
 adis_initial_startup

On Mon, 10 Feb 2020 15:26:04 +0200
Alexandru Ardelean <alexandru.ardelean@...log.com> wrote:

> Each driver/chip that wants to validate it's product id, can now
> specify a 'prod_id_reg' and an expected 'prod_id' value.
> The 'prod_id' value is intentionally left 0 (uninitialized). There aren't
> (yet) any product IDs with value 0; this enforces that both 'prod_id_reg'
> and 'prod_id' are specified.
> 
> At the very least, this routine validates that the SPI connection to the
> ADIS chip[s] works well.
> 
> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@...log.com>
Applied.  Thanks,

Jonathan

> ---
>  drivers/iio/imu/adis.c       | 23 ++++++++++++++++++++++-
>  include/linux/iio/imu/adis.h |  5 +++++
>  2 files changed, 27 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/imu/adis.c b/drivers/iio/imu/adis.c
> index 0bd6e32cf577..a8afd01de4f3 100644
> --- a/drivers/iio/imu/adis.c
> +++ b/drivers/iio/imu/adis.c
> @@ -373,6 +373,10 @@ static int adis_self_test(struct adis *adis)
>   * via GPIOLIB. If no pin is configured a SW reset will be performed.
>   * The RST pin for the ADIS devices should be configured as ACTIVE_LOW.
>   *
> + * After the self-test operation is performed, the function will also check
> + * that the product ID is as expected. This assumes that drivers providing
> + * 'prod_id_reg' will also provide the 'prod_id'.
> + *
>   * Returns 0 if the device is operational, a negative error code otherwise.
>   *
>   * This function should be called early on in the device initialization sequence
> @@ -382,6 +386,7 @@ int __adis_initial_startup(struct adis *adis)
>  {
>  	const struct adis_timeout *timeouts = adis->data->timeouts;
>  	struct gpio_desc *gpio;
> +	uint16_t prod_id;
>  	int ret;
>  
>  	/* check if the device has rst pin low */
> @@ -401,7 +406,23 @@ int __adis_initial_startup(struct adis *adis)
>  			return ret;
>  	}
>  
> -	return adis_self_test(adis);
> +	ret = adis_self_test(adis);
> +	if (ret)
> +		return ret;
> +
> +	if (!adis->data->prod_id_reg)
> +		return 0;
> +
> +	ret = adis_read_reg_16(adis, adis->data->prod_id_reg, &prod_id);
> +	if (ret)
> +		return ret;
> +
> +	if (prod_id != adis->data->prod_id)
> +		dev_warn(&adis->spi->dev,
> +			 "Device ID(%u) and product ID(%u) do not match.",
> +			 adis->data->prod_id, prod_id);
> +
> +	return 0;
>  }
>  EXPORT_SYMBOL_GPL(__adis_initial_startup);
>  
> diff --git a/include/linux/iio/imu/adis.h b/include/linux/iio/imu/adis.h
> index b7feca4e5f26..ac7cfd073804 100644
> --- a/include/linux/iio/imu/adis.h
> +++ b/include/linux/iio/imu/adis.h
> @@ -41,6 +41,8 @@ struct adis_timeout {
>   * @glob_cmd_reg: Register address of the GLOB_CMD register
>   * @msc_ctrl_reg: Register address of the MSC_CTRL register
>   * @diag_stat_reg: Register address of the DIAG_STAT register
> + * @prod_id_reg: Register address of the PROD_ID register
> + * @prod_id: Product ID code that should be expected when reading @prod_id_reg
>   * @self_test_reg: Register address to request self test command
>   * @status_error_msgs: Array of error messgaes
>   * @status_error_mask:
> @@ -54,6 +56,9 @@ struct adis_data {
>  	unsigned int glob_cmd_reg;
>  	unsigned int msc_ctrl_reg;
>  	unsigned int diag_stat_reg;
> +	unsigned int prod_id_reg;
> +
> +	unsigned int prod_id;
>  
>  	unsigned int self_test_mask;
>  	unsigned int self_test_reg;