Re: [PATCH v2 1/3] x86: add support for Huawei WMI hotkeys.

[ayman.bagabas@gmail.com]

On Fri, 2018-11-02 at 20:20 +0200, Andy Shevchenko wrote:
> On Fri, Nov 2, 2018 at 6:11 AM Ayman Bagabas <ayman.bagabas@gmail.com
> > wrote:
> > 
> > This driver adds support for missing hotkeys on some Huawei
> > laptops.
> > Currently, only Huawei Matebook X Pro is supported. The driver
> > recognizes the following keys: brightness keys, micmute, wlan, and
> > Huawei special key. The brightness keys are ignored since they work
> > out
> > of the box.
> > +config HUAWEI_LAPTOP
> > +       tristate "Huawei WMI hotkeys driver"
> > +       depends on ACPI
> > +       depends on ACPI_WMI
> 
> 
> > +       depends on INPUT
> > +       select INPUT_SPARSEKMAP
> > +       help
> > +         This driver provides support for Huawei WMI hotkeys.
> > +         It enables the missing keys and adds support to micmute
> > +         led found on these laptops.q
> > +         Supported devices are:
> > +         - Matebook X Pro
> 
> 
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + *  Huawei WMI Hotkeys Driver
> > + *
> > + *  Copyright (C) 2018           Ayman Bagabas <
> > ayman.bagabas@gmail.com>
> > + *
> > + *  This program is free software: you can redistribute it and/or
> > modify
> > + *  it under the terms of the GNU General Public License as
> > published by
> > + *  the Free Software Foundation, either version 2 of the License,
> > or
> > + *  (at your option) any later version.
> > + *
> > + *  This program is distributed in the hope that it will be
> > useful,
> > + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > + *  GNU General Public License for more details.
> > + *
> > + *  You should have received a copy of the GNU General Public
> > License
> > + *  along with this program.  If not, see <
> > https://www.gnu.org/licenses/>.
> > + *
> > + */
> > +MODULE_LICENSE("GPL");
> 
> 
> Here you have the following issues:
> - inconsistency between IDs for license (fix accordingly)
> - SDPX _and_ License header (remove latter)
> 
> 
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/init.h>
> 
> Choose one of them.
> 
> > +#include <linux/input.h>
> > +#include <linux/input/sparse-keymap.h>
> > +#include <linux/acpi.h>
> > +#include <linux/wmi.h>
> 
> Please, keep in order.

What order do I have to follow? Does this look right?
module.h
init.h
apci.h
wmi.h
input.h
sparse-keymap.h

> 
> > +static const struct key_entry huawei_wmi_keymap[] __initconst = {
> > +               { KE_IGNORE, 0x281, { KEY_BRIGHTNESSDOWN } },
> > +               { KE_IGNORE, 0x282, { KEY_BRIGHTNESSUP } },
> > +               { KE_KEY,       0x287, { KEY_MICMUTE } },
> > +               { KE_KEY,       0x289, { KEY_WLAN } },
> > +               // Huawei |M| button
> > +               { KE_KEY,       0x28a, { KEY_PROG1 } },
> > +               { KE_END,       0 }
> > +};
> > +
> > +struct huawei_wmi_device {
> > +       struct input_dev *inputdev;
> > +};
> 
> Apparently no need to have this, you may use struct input_dev
> directly, isn't it?
> 
> > +static struct huawei_wmi_device *wmi_device;
> 
> No global variables, please.

What about input_dev as a global variable? How would
input_unregister_device access input_dev on exit if it wasn't global?

> 
> > +int huawei_wmi_micmute_led_set(bool on)
> > +{
> > +       u32 args = (on) ? MICMUTE_LED_ON : MICMUTE_LED_OFF;
> 
> Redundant parens.
> 
> > +       struct acpi_buffer input = { (acpi_size)sizeof(args), &args
> > };
> > +       acpi_status status;
> > +
> > +       status = wmi_evaluate_method(AMW0_GUID, 0, 1, &input,
> > NULL);
> > +       if (ACPI_FAILURE(status))
> > +               return status;
> > +
> > +       return 0;
> > +}
> > +static void huawei_wmi_process_key(struct input_dev *input_dev,
> > int code)
> > +{
> > +       const struct key_entry *key;
> > +
> > +       key = sparse_keymap_entry_from_scancode(input_dev, code);
> > +
> 
> This blank line is redundant.
> 
> > +       if (!key) {
> > +               pr_info("%s: Unknown key pressed, code: 0x%04x\n",
> > +                                       MODULE_NAME, code);
> 
> dev_info(); no MODULE_NAME, please.
> 
> > +               return;
> > +       }
> > +
> > +       sparse_keymap_report_entry(input_dev, key, 1, true);
> > +}
> > +static void huawei_wmi_notify(u32 value, void *context)
> > +{
> > +       struct acpi_buffer response = { ACPI_ALLOCATE_BUFFER, NULL
> > };
> > +       union acpi_object *obj;
> > +       acpi_status status;
> > +
> > +       status = wmi_get_event_data(value, &response);
> > +       if (ACPI_FAILURE(status)) {
> > +               pr_err("%s: Bad event status 0x%x\n",
> > +                                       MODULE_NAME, status);
> 
> No MODULE_NAME, please.
> If needed, use pr_fmt() macro.
> 
> But I'm pretty sure you may pass pointer to input device and use
> dev_err().
> 
> > +               return;
> > +       }
> > +
> > +       obj = (union acpi_object *)response.pointer;
> > +
> 
> No redundant blank lines, please.
> 
> > +       if (!obj)
> > +               return;
> > +
> > +       if (obj->type == ACPI_TYPE_INTEGER)
> > +               huawei_wmi_process_key(wmi_device->inputdev,
> > +                                                       obj-
> > >integer.value);
> > +       else
> > +               pr_info("%s: Unknown response received %d\n",
> > +                                       MODULE_NAME, obj->type);
> 
> Ditto about module name.
> 
> > +
> > +       kfree(response.pointer);
> > +}
> > +
> > +static int huawei_input_init(void)
> > +{
> > +       acpi_status status;
> > +       int err;
> > +       status = wmi_install_notify_handler(EVENT_GUID,
> > +                       huawei_wmi_notify,
> > +                       NULL);
> 
> Pointer to the input device instead of NULL.
> 
> > +
> 
> No redundant blank lines, please.
> 
> > +       if (ACPI_FAILURE(status)) {
> > +               err = -EIO;
> > +               goto err_free_dev;
> > +       }
> > +}
> 
> 
> > +       wmi_device = kmalloc(sizeof(struct huawei_wmi_device),
> > GFP_KERNEL);
> 
> sizeof(*wmi_device)
> 
> > +       if (!wmi_device)
> > +               return -ENOMEM;
> > +}
> 
> 
> > +       pr_debug("%s: Driver unloaded successfully\n",
> > MODULE_NAME);
> 
> Noise.
> 
> --
> With Best Regards,
> Andy Shevchenko