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Message-ID: <8bd83f45-5278-e817-3f65-88fafd0ad3f4@collabora.com>
Date: Wed, 11 May 2022 20:59:07 +0500
From: Muhammad Usama Anjum <usama.anjum@...labora.com>
To: Andy Shevchenko <andy.shevchenko@...il.com>
Cc: usama.anjum@...labora.com, "Rafael J. Wysocki" <rafael@...nel.org>,
Len Brown <lenb@...nel.org>,
Hans de Goede <hdegoede@...hat.com>,
Mark Gross <markgross@...nel.org>,
Benson Leung <bleung@...omium.org>,
Enric Balletbo i Serra <eballetbo@...il.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Collabora Kernel ML <kernel@...labora.com>,
Guenter Roeck <groeck@...omium.org>,
Dmitry Torokhov <dtor@...omium.org>,
Gwendal Grignou <gwendal@...omium.org>, vbendeb@...omium.org,
Andy Shevchenko <andy@...radead.org>,
Ayman Bagabas <ayman.bagabas@...il.com>,
Benjamin Tissoires <benjamin.tissoires@...hat.com>,
Blaž Hrastnik <blaz@...n.io>,
Darren Hart <dvhart@...radead.org>,
Dmitry Torokhov <dmitry.torokhov@...il.com>,
Jeremy Soller <jeremy@...tem76.com>,
Mattias Jacobsson <2pi@....nu>,
Mauro Carvalho Chehab <mchehab+samsung@...nel.org>,
Rajat Jain <rajatja@...gle.com>,
Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
Platform Driver <platform-driver-x86@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
"Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
chrome-platform@...ts.linux.dev
Subject: Re: [PATCH RESEND v11] platform/chrome: Add ChromeOS ACPI device
driver
Hi Andy,
Thank you for reviewing.
On 5/10/22 2:33 PM, Andy Shevchenko wrote:
> On Tue, May 10, 2022 at 8:44 AM Muhammad Usama Anjum
> <usama.anjum@...labora.com> wrote:
>>
>> From: Enric Balletbo i Serra <enric.balletbo@...labora.com>
>>
>> The x86 Chromebooks have the ChromeOS ACPI device. This driver attaches
>> to the ChromeOS ACPI device and exports the values reported by ACPI in a
>> sysfs directory. This data isn't present in ACPI tables when read
>> through ACPI tools, hence a driver is needed to do it. The driver gets
>> data from firmware using the ACPI component of the kernel. The ACPI values
>> are presented in string form (numbers as decimal values) or binary
>> blobs, and can be accessed as the contents of the appropriate read only
>> files in the standard ACPI device's sysfs directory tree. This data is
>> consumed by the ChromeOS user space.
>
>> Cc: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>> Cc: Dmitry Torokhov <dmitry.torokhov@...il.com>
>> Cc: Hans de Goede <hdegoede@...hat.com>
>
> You can use --cc parameter to `git send-email` instead of putting
> these lines in the commit message.
>
> ...
>
>> +#define DEV_ATTR(_var, _name) \
>> + static struct device_attribute dev_attr_##_var = \
>> + __ATTR(_name, 0444, chromeos_first_level_attr_show, NULL);
>> +
>
> Why not ATTR_RO()?
It'll not work as attribute name has . in it.
>
> ...
>
>> +#define GPIO_ATTR_GROUP(_group, _name, _num) \
>> + static umode_t attr_is_visible_gpio_##_num(struct kobject *kobj, \
>> + struct attribute *attr, int n) \
>> + { \
>> + if (_num < chromeos_acpi_gpio_groups) \
>> + return attr->mode; \
>
>> + else \
>
> Redundant.
We are deciding on run time that how many GPIO attribute groups need to
be shown. chromeos_acpi_gpio_groups is set at run time. I don't see why
`else` can be redundant here.
>
>> + return 0; \
>> + } \
>> + static ssize_t chromeos_attr_show_gpio_##_num(struct device *dev, \
>> + struct device_attribute *attr, \
>> + char *buf) \
>> + { \
>> + char name[ACPI_ATTR_NAME_LEN + 1]; \
>> + int ret, num; \
>> + \
>> + ret = parse_attr_name(attr->attr.name, name, &num); \
>> + if (ret) \
>> + return ret; \
>
>> + ret = chromeos_acpi_evaluate_method(dev, _num, num, name, buf); \
>> + if (ret < 0) \
>> + ret = 0; \
>
> Below I saw the same code, why is the error ignored?
>
I'll return the error in both places.
>> + return ret; \
>> + } \
>> + static struct device_attribute dev_attr_0_##_group = \
>> + __ATTR(GPIO.0, 0444, chromeos_attr_show_gpio_##_num, NULL); \
>> + static struct device_attribute dev_attr_1_##_group = \
>> + __ATTR(GPIO.1, 0444, chromeos_attr_show_gpio_##_num, NULL); \
>> + static struct device_attribute dev_attr_2_##_group = \
>> + __ATTR(GPIO.2, 0444, chromeos_attr_show_gpio_##_num, NULL); \
>> + static struct device_attribute dev_attr_3_##_group = \
>> + __ATTR(GPIO.3, 0444, chromeos_attr_show_gpio_##_num, NULL); \
>> + \
>> + static struct attribute *attrs_##_group[] = { \
>> + &dev_attr_0_##_group.attr, \
>> + &dev_attr_1_##_group.attr, \
>> + &dev_attr_2_##_group.attr, \
>> + &dev_attr_3_##_group.attr, \
>> + NULL \
>> + }; \
>> + static const struct attribute_group attr_group_##_group = { \
>> + .name = _name, \
>> + .is_visible = attr_is_visible_gpio_##_num, \
>
>> + .attrs = attrs_##_group \
>
> Keep a comma here.
Is there any particular reason for it? If there is, I'll add commas to
all the structures.
...
>
> ...
>
>> +static int parse_attr_name(const char *name, char *attr_name, int *attr_num)
>> +{
>> + int ret = 0;
>> +
>> + strscpy(attr_name, name, ACPI_ATTR_NAME_LEN + 1);
>> +
>> + if (strlen(name) > ACPI_ATTR_NAME_LEN)
>
> This seems strange, esp. taking into account that strscpy() returns that.
>
> int ret;
>
> ret = strscpy(...);
> if (ret == -E2BIG)
> return kstrtoint(...);
>
> return 0;
This is very nice way to do it. I'll update.
...
--
Muhammad Usama Anjum
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