Date:   Thu, 9 Mar 2023 08:52:24 +0100
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Ye Xiang <xiang.ye@intel.com>
Cc:     Arnd Bergmann <arnd@arndb.de>,
        Matthias Kaehlcke <mka@chromium.org>,
        Lee Jones <lee@kernel.org>, Wolfram Sang <wsa@kernel.org>,
        Tyrone Ting <kfting@nuvoton.com>,
        Mark Brown <broonie@kernel.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        Bartosz Golaszewski <brgl@bgdev.pl>, linux-usb@vger.kernel.org,
        linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-spi@vger.kernel.org, linux-gpio@vger.kernel.org,
        srinivas.pandruvada@intel.com, heikki.krogerus@linux.intel.com,
        andriy.shevchenko@linux.intel.com, sakari.ailus@linux.intel.com,
        zhifeng.wang@intel.com, wentong.wu@intel.com, lixu.zhang@intel.com
Subject: Re: [PATCH v4 1/5] mfd: Add support for Intel LJCA device
Message-ID: <ZAmQOIh/71rY4Pa4@kroah.com>
References: <20230309071100.2856899-1-xiang.ye@intel.com>
 <20230309071100.2856899-2-xiang.ye@intel.com>
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Precedence: bulk

On Thu, Mar 09, 2023 at 03:10:56PM +0800, Ye Xiang wrote:
> +static int ljca_mng_get_version(struct ljca_stub *stub, char *buf)
> +{
> +	struct fw_version version = {};
> +	unsigned int len = sizeof(version);
> +	int ret;
> +
> +	ret = ljca_stub_write(stub, LJCA_MNG_GET_VERSION, NULL, 0, &version, &len, true,
> +			      LJCA_USB_WRITE_ACK_TIMEOUT_MS);
> +	if (ret)
> +		return ret;
> +
> +	if (len != sizeof(version)) {
> +		dev_err(&stub->intf->dev, "get version failed, len:%d\n", len);
> +		return -EINVAL;
> +	}
> +
> +	return sysfs_emit(buf, "%d.%d.%d.%d\n", version.major, version.minor,
> +			  le16_to_cpu(version.patch), le16_to_cpu(version.build));
> +}

You have sysfs files, yet no Documentation/ABI/ entries?  That's not
allowed, you know this :(

> +static ssize_t cmd_store(struct device *dev, struct device_attribute *attr, const char *buf,
> +			 size_t count)
> +{
> +	struct usb_interface *intf = to_usb_interface(dev);
> +	struct ljca_dev *ljca_dev = usb_get_intfdata(intf);
> +	struct ljca_stub *mng_stub = ljca_stub_find(ljca_dev, LJCA_MNG_STUB);
> +	struct ljca_stub *diag_stub = ljca_stub_find(ljca_dev, LJCA_DIAG_STUB);
> +
> +	if (sysfs_streq(buf, "dfu"))
> +		ljca_mng_set_dfu_mode(mng_stub);
> +	else if (sysfs_streq(buf, "debug"))
> +		ljca_diag_set_trace_level(diag_stub, 3);

Sorry, but no, you can't do this in a sysfs file.

> +
> +	return count;
> +}
> +
> +static ssize_t cmd_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +	return sysfs_emit(buf, "%s\n", "supported cmd: [dfu, debug]");

sysfs files do not show "help text".

thanks,

greg k-h