linux-kernel - Re: [PATCH v4] platform/chrome: wilco_ec: Add debugfs test

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Date:   Mon, 23 Sep 2019 17:11:16 -0700
From:   Benson Leung <bleung@...gle.com>
To:     Daniel Campello <campello@...omium.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Enric Balletbo i Serra <enric.balletbo@...labora.com>,
        Benson Leung <bleung@...omium.org>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Duncan Laurie <dlaurie@...gle.com>,
        Nick Crews <ncrews@...omium.org>
Subject: Re: [PATCH v4] platform/chrome: wilco_ec: Add debugfs test_event file

Hi Daniel,

Thanks for sending this.

On Wed, Sep 18, 2019 at 02:43:16PM -0600, Daniel Campello wrote:
> This change introduces a new debugfs file 'test_event' that when written
> to causes the EC to generate a test event.

Please mention that this adds a second sub cmd for the test event, and
pulls out send_ec_cmd to be a common helper between h1_gpio_get and
test_event_set.

> 
> Signed-off-by: Daniel Campello <campello@...omium.org>
> ---
> Changes for v2:
>   - Cleaned up and added comments.
>   - Renamed and updated function signature from write_to_mailbox to
>     send_ec_cmd.
> Changes for v3:
>   - Switched NULL format string to empty format string
>   - Renamed val parameter on send_ec_cmd to out_val
> Changes for v4:
>   - Provided a format string to avoid -Wformat-zero-length warning
> 
>  drivers/platform/chrome/wilco_ec/debugfs.c | 46 +++++++++++++++++-----
>  1 file changed, 36 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/platform/chrome/wilco_ec/debugfs.c b/drivers/platform/chrome/wilco_ec/debugfs.c
> index 8d65a1e2f1a3..ba86c38421ff 100644
> --- a/drivers/platform/chrome/wilco_ec/debugfs.c
> +++ b/drivers/platform/chrome/wilco_ec/debugfs.c
> @@ -160,29 +160,29 @@ static const struct file_operations fops_raw = {
> 
>  #define CMD_KB_CHROME		0x88
>  #define SUB_CMD_H1_GPIO		0x0A
> +#define SUB_CMD_TEST_EVENT	0x0B
> 
> -struct h1_gpio_status_request {
> +struct ec_request {
>  	u8 cmd;		/* Always CMD_KB_CHROME */
>  	u8 reserved;
> -	u8 sub_cmd;	/* Always SUB_CMD_H1_GPIO */
> +	u8 sub_cmd;
>  } __packed;
> 
> -struct hi_gpio_status_response {
> +struct ec_response {
>  	u8 status;	/* 0 if allowed */
> -	u8 val;		/* BIT(0)=ENTRY_TO_FACT_MODE, BIT(1)=SPI_CHROME_SEL */
> +	u8 val;
>  } __packed;
> 
> -static int h1_gpio_get(void *arg, u64 *val)
> +static int send_ec_cmd(struct wilco_ec_device *ec, u8 sub_cmd, u8 *out_val)
>  {
> -	struct wilco_ec_device *ec = arg;
> -	struct h1_gpio_status_request rq;
> -	struct hi_gpio_status_response rs;
> +	struct ec_request rq;
> +	struct ec_response rs;
>  	struct wilco_ec_message msg;
>  	int ret;
> 
>  	memset(&rq, 0, sizeof(rq));
>  	rq.cmd = CMD_KB_CHROME;
> -	rq.sub_cmd = SUB_CMD_H1_GPIO;
> +	rq.sub_cmd = sub_cmd;
> 
>  	memset(&msg, 0, sizeof(msg));
>  	msg.type = WILCO_EC_MSG_LEGACY;
> @@ -196,13 +196,37 @@ static int h1_gpio_get(void *arg, u64 *val)
>  	if (rs.status)
>  		return -EIO;
> 
> -	*val = rs.val;
> +	*out_val = rs.val;
> 
>  	return 0;
>  }
> +/**

Minor nit. Add one line of whitespace before this comment start.

> + * h1_gpio_get() - Gets h1 gpio status.
> + * @arg: The wilco EC device.
> + * @val: BIT(0)=ENTRY_TO_FACT_MODE, BIT(1)=SPI_CHROME_SEL
> + */
> +static int h1_gpio_get(void *arg, u64 *val)
> +{
> +	return send_ec_cmd(arg, SUB_CMD_H1_GPIO, (u8 *)val);
> +}
> 
>  DEFINE_DEBUGFS_ATTRIBUTE(fops_h1_gpio, h1_gpio_get, NULL, "0x%02llx\n");
> 
> +/**
> + * test_event_set() - Sends command to EC to cause an EC test event.
> + * @arg: The wilco EC device.
> + * @val: unused.
> + */
> +static int test_event_set(void *arg, u64 val)
> +{
> +	u8 ret;
> +
> +	return send_ec_cmd(arg, SUB_CMD_TEST_EVENT, &ret);
> +}
> +
> +/* Format is unused since it is only required for get method which is NULL */
> +DEFINE_DEBUGFS_ATTRIBUTE(fops_test_event, NULL, test_event_set, "%llu\n");
> +
>  /**
>   * wilco_ec_debugfs_probe() - Create the debugfs node
>   * @pdev: The platform device, probably created in core.c
> @@ -226,6 +250,8 @@ static int wilco_ec_debugfs_probe(struct platform_device *pdev)
>  	debugfs_create_file("raw", 0644, debug_info->dir, NULL, &fops_raw);
>  	debugfs_create_file("h1_gpio", 0444, debug_info->dir, ec,
>  			    &fops_h1_gpio);
> +	debugfs_create_file("test_event", 0200, debug_info->dir, ec,
> +			    &fops_test_event);
> 
>  	return 0;
>  }
> --
> 2.23.0.237.gc6a4ce50a0-goog
> 

-- 
Benson Leung
Staff Software Engineer
Chrome OS Kernel
Google Inc.
bleung@...gle.com
Chromium OS Project
bleung@...omium.org

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