Date:	Tue, 17 Jun 2014 15:46:02 +0200
From:	Johan Hovold <johan@...nel.org>
To:	Janne Kanniainen <janne.kanniainen@...il.com>
Cc:	jkosina@...e.cz, johan@...nel.org, cooloney@...il.com,
	linux-kernel@...r.kernel.org, linux-leds@...r.kernel.org,
	linux-usb@...r.kernel.org, linux-input@...r.kernel.org
Subject: Re: [PATCH v6] leds: USB: HID: Add support for MSI GT683R led panels

On Tue, Jun 17, 2014 at 01:01:55AM +0300, Janne Kanniainen wrote:
> This driver adds support for USB controlled led panels that exists in
> MSI GT683R laptop
> 
> Signed-off-by: Janne Kanniainen <janne.kanniainen@...il.com>
> ---
> Changes in v2:
> 	- sorted headers to alphabetic order
> 	- using devm_kzalloc
> 	- using BIT(n)
> 	- using usb_control_msg instead of usb_submit_urb
> 	- removing unneeded code
> 
> Changes in v3:
> 	- implemented as HID device
> 	- some cleanups and bug fixes
> 
> Changes in v4:
> 	- more cleanups
> 	- support for selecting leds
> 	- suppport for selecting status
> 
> Changes in v5:
> 	- mode attribute documented under Documentation/ABI
> 	- made array for led_classdev
> 	- led devices uses now recommended naming scheme
> 
> Changes in v6:
> 	- flush_work added
> 	- using hid device name instead of hard coded gt683r
> 	- allocating name buffers with devm_kzalloc
> 
> There was a bug with "for", so I fixed it.

Then it really was a v7 and should have been marked as such, right?
 
>  .../ABI/testing/sysfs-class-hid-driver-gt683r      |  14 +
>  drivers/hid/Kconfig                                |  16 ++
>  drivers/hid/Makefile                               |   1 +
>  drivers/hid/hid-core.c                             |   1 +
>  drivers/hid/hid-gt683r.c                           | 318 +++++++++++++++++++++
>  drivers/hid/hid-ids.h                              |   2 +-
>  drivers/hid/usbhid/hid-quirks.c                    |   2 +-
>  7 files changed, 352 insertions(+), 2 deletions(-)
>  create mode 100644 Documentation/ABI/testing/sysfs-class-hid-driver-gt683r
>  create mode 100644 drivers/hid/hid-gt683r.c
> 
> diff --git a/Documentation/ABI/testing/sysfs-class-hid-driver-gt683r b/Documentation/ABI/testing/sysfs-class-hid-driver-gt683r
> new file mode 100644
> index 0000000..6d0bd80
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-class-hid-driver-gt683r
> @@ -0,0 +1,14 @@
> +What:		/sys/class/hidraw/<hidraw>/device/mode

Perhaps you should name this "leds_mode" or "led_panel_mode", or similar
(only change the attribute name, code is fine otherwise). This is an
attribute of the parent HID device, but it's not really apparent what
just "mode" would mean for such a device.

> +Date:		Jun 2014
> +KernelVersion:	3.17
> +Contact:	Janne Kanniainen <janne.kanniainen@...il.com>
> +Description:
> +		Set the mode of LEDs
> +
> +		0 - normal
> +		1 - audio
> +		2 - breathing
> +
> +		Normal: LEDs are on

Change this to "LEDs are fully on when enabled", or similar?

> +		Audio:  LEDs brightness depends on sound level
> +		Breathing: LEDs brightness varies at human breathing rate
> \ No newline at end of file
> diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
> index 7af9d0b..b88cabd 100644
> --- a/drivers/hid/Kconfig
> +++ b/drivers/hid/Kconfig
> @@ -261,6 +261,22 @@ config HOLTEK_FF
>  	  Say Y here if you have a Holtek On Line Grip based game controller
>  	  and want to have force feedback support for it.
>  
> +config HID_GT683R
> +	tristate "MSI GT68xR LED support"
> +	depends on LEDS_CLASS && USB_HID
> +	---help---
> +	Say Y here if you want to enable support for the MSI GT68xR LEDS
> +
> +	This driver support following modes:
> +	  - Normal: LEDs are on
> +	  - Audio:  LEDs brightness depends on sound level
> +	  - Breathing: LEDs brightness varies at human breathing rate

This might need an update as well.

> +
> +	You can also select which leds you want to enable.

You could drop this line, and just say "enable support for the three
MSI" LEDs above?

> +
> +	Currently the following devices are know to be supported:
> +	  - MSI GT683R
> +
>  config HID_HUION
>  	tristate "Huion tablets"
>  	depends on USB_HID
> diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
> index fc712dd..7129311 100644
> --- a/drivers/hid/Makefile
> +++ b/drivers/hid/Makefile
> @@ -48,6 +48,7 @@ obj-$(CONFIG_HID_EMS_FF)	+= hid-emsff.o
>  obj-$(CONFIG_HID_ELECOM)	+= hid-elecom.o
>  obj-$(CONFIG_HID_ELO)		+= hid-elo.o
>  obj-$(CONFIG_HID_EZKEY)		+= hid-ezkey.o
> +obj-$(CONFIG_HID_GT683R)	+= hid-gt683r.o
>  obj-$(CONFIG_HID_GYRATION)	+= hid-gyration.o
>  obj-$(CONFIG_HID_HOLTEK)	+= hid-holtek-kbd.o
>  obj-$(CONFIG_HID_HOLTEK)	+= hid-holtek-mouse.o
> diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
> index da52279..ec88fdb 100644
> --- a/drivers/hid/hid-core.c
> +++ b/drivers/hid/hid-core.c
> @@ -1827,6 +1827,7 @@ static const struct hid_device_id hid_have_special_driver[] = {
>  	{ HID_USB_DEVICE(USB_VENDOR_ID_MICROSOFT, USB_DEVICE_ID_WIRELESS_OPTICAL_DESKTOP_3_0) },
>  	{ HID_USB_DEVICE(USB_VENDOR_ID_MICROSOFT, USB_DEVICE_ID_MS_OFFICE_KB) },
>  	{ HID_USB_DEVICE(USB_VENDOR_ID_MONTEREY, USB_DEVICE_ID_GENIUS_KB29E) },
> +	{ HID_USB_DEVICE(USB_VENDOR_ID_MSI, USB_DEVICE_ID_MSI_GT683R_LED_PANEL) },
>  	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN) },
>  	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_1) },
>  	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_2) },
> diff --git a/drivers/hid/hid-gt683r.c b/drivers/hid/hid-gt683r.c
> new file mode 100644
> index 0000000..1b16250
> --- /dev/null
> +++ b/drivers/hid/hid-gt683r.c
> @@ -0,0 +1,318 @@
> +/*
> + * MSI GT683R led driver
> + *
> + * Copyright (c) 2014 Janne Kanniainen <janne.kanniainen@...il.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.
> + *
> + */
> +
> +#include <linux/device.h>
> +#include <linux/hid.h>
> +#include <linux/kernel.h>
> +#include <linux/leds.h>
> +#include <linux/module.h>
> +
> +#include "hid-ids.h"
> +
> +#define GT683R_BUFFER_SIZE			8
> +
> +/*
> + * GT683R_LED_OFF: all LEDs are off
> + * GT683R_LED_AUDIO: LEDs brightness depends
> + * on sound level
> + * GT683R_LED_BREATHING: LEDs brightness varies
> + * at human breathing rate

No need to break these two lines (they would still be below 80 cols
wide).

> + * GT683R_LED_NORMAL: LEDs are on
> + */
> +enum gt683r_led_mode {
> +	GT683R_LED_OFF = 0,
> +	GT683R_LED_AUDIO = 2,
> +	GT683R_LED_BREATHING = 3,
> +	GT683R_LED_NORMAL = 5
> +};
> +
> +enum gt683r_panels {
> +	GT683R_LED_BACK,
> +	GT683R_LED_SIDE,
> +	GT683R_LED_FRONT,

Perhaps initialise these three explicitly as the order really isn't
arbitrary?

> +	GT683R_LED_COUNT,
> +};
> +
> +static const char * const gt683r_panel_names[] = {
> +	"back",
> +	"side",
> +	"front",
> +};
> +
> +struct gt683r_led {
> +	struct hid_device *hdev;
> +	struct led_classdev led_devs[GT683R_LED_COUNT];
> +	struct mutex lock;
> +	struct work_struct work;
> +	enum led_brightness brightnesses[GT683R_LED_COUNT];
> +	enum gt683r_led_mode mode;
> +};
> +
> +static const struct hid_device_id gt683r_led_id[] = {
> +	{ HID_USB_DEVICE(USB_VENDOR_ID_MSI, USB_DEVICE_ID_MSI_GT683R_LED_PANEL) },
> +	{ }
> +};
> +
> +static void gt683r_brightness_set(struct led_classdev *led_cdev,
> +				enum led_brightness brightness)
> +{
> +	int i;
> +	struct device *dev = led_cdev->dev->parent;
> +	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
> +	struct gt683r_led *led = hid_get_drvdata(hdev);
> +
> +	for (i = 0; i < GT683R_LED_COUNT; i++) {
> +		if (&led->led_devs[i] == led_cdev)
> +			break;
> +	}
> +
> +	if (i < GT683R_LED_COUNT) {
> +		led->brightnesses[i] = brightness;
> +		schedule_work(&led->work);
> +	}
> +}
> +
> +static ssize_t mode_show(struct device *dev,
> +				struct device_attribute *attr,
> +				char *buf)
> +{
> +	u8 sysfs_mode;
> +	struct hid_device *hdev =
> +		container_of(dev, struct hid_device, dev);

No need to break this (still < 80 cols).

> +	struct gt683r_led *led = hid_get_drvdata(hdev);
> +
> +	if (led->mode == GT683R_LED_NORMAL)
> +		sysfs_mode = 0;
> +	else if (led->mode == GT683R_LED_AUDIO)
> +		sysfs_mode = 1;
> +	else
> +		sysfs_mode = 2;
> +
> +	return scnprintf(buf, PAGE_SIZE, "%u\n", sysfs_mode);
> +}
> +
> +static ssize_t mode_store(struct device *dev,
> +				struct device_attribute *attr,
> +				const char *buf, size_t count)
> +{
> +	u8 sysfs_mode;
> +	struct hid_device *hdev =
> +		container_of(dev, struct hid_device, dev);

No need to break this (still < 80 cols).

> +	struct gt683r_led *led = hid_get_drvdata(hdev);
> +
> +	mutex_lock(&led->lock);
> +
> +	if (kstrtou8(buf, 10, &sysfs_mode) || sysfs_mode > 2) {
> +		count = -EINVAL;
> +		goto fail;
> +	}
> +
> +	if (sysfs_mode == 0)
> +		led->mode = GT683R_LED_NORMAL;
> +	else if (sysfs_mode == 1)
> +		led->mode = GT683R_LED_AUDIO;
> +	else
> +		led->mode = GT683R_LED_BREATHING;
> +
> +fail:
> +	mutex_unlock(&led->lock);
> +
> +	if (count != -EINVAL)
> +		schedule_work(&led->work);
> +
> +	return count;
> +}

This could be simplified somewhat as the lock only needs to protect the
assignment to led->mode.

(Glad to see you realised I meant kstrouX when I wrote snprintf. ;))

> +
> +static int gt683r_led_snd_msg(struct gt683r_led *led, u8 *msg)
> +{
> +	int ret;
> +
> +	ret = hid_hw_raw_request(led->hdev, msg[0], msg, GT683R_BUFFER_SIZE,
> +				HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
> +	if (ret != GT683R_BUFFER_SIZE) {
> +		hid_err(led->hdev,
> +			"failed to send set report request: %i\n", ret);
> +		if (ret < 0)
> +			return ret;
> +		return -EIO;
> +	}
> +
> +	return 0;
> +}
> +
> +static int gt683r_leds_set(struct gt683r_led *led, u8 leds)
> +{
> +	int ret;
> +	u8 *buffer;
> +
> +	buffer = kzalloc(GT683R_BUFFER_SIZE, GFP_KERNEL);
> +	if (!buffer)
> +		return -ENOMEM;
> +
> +	buffer[0] = 0x01;
> +	buffer[1] = 0x02;
> +	buffer[2] = 0x30;
> +	buffer[3] = leds;
> +	ret = gt683r_led_snd_msg(led, buffer);
> +
> +	kfree(buffer);
> +	return ret;
> +}
> +
> +static int gt683r_mode_set(struct gt683r_led *led, u8 mode)
> +{
> +	int ret;
> +	u8 *buffer;
> +
> +	buffer = kzalloc(GT683R_BUFFER_SIZE, GFP_KERNEL);
> +	if (!buffer)
> +		return -ENOMEM;
> +
> +	buffer[0] = 0x01;
> +	buffer[1] = 0x02;
> +	buffer[2] = 0x20;
> +	buffer[3] = mode;
> +	buffer[4] = 0x01;
> +	ret = gt683r_led_snd_msg(led, buffer);
> +
> +	kfree(buffer);
> +	return ret;
> +}
> +
> +static void gt683r_led_work(struct work_struct *work)
> +{
> +	u8 leds = 0, mode;

Try to stick to one definition per line (throughout), especially if
you're initialising as well.

> +	struct gt683r_led *led =
> +		container_of(work, struct gt683r_led, work);
> +
> +	mutex_lock(&led->lock);
> +
> +	if (led->brightnesses[GT683R_LED_BACK])
> +		leds |= BIT(GT683R_LED_BACK);
> +
> +	if (led->brightnesses[GT683R_LED_SIDE])
> +		leds |= BIT(GT683R_LED_SIDE);
> +
> +	if (led->brightnesses[GT683R_LED_FRONT])
> +		leds |= BIT(GT683R_LED_FRONT);

This could of course be implemented as a loop as well, if you want...

> +
> +	if (gt683r_leds_set(led, leds))
> +		goto fail;
> +
> +	if (leds)
> +		mode = led->mode;
> +	else
> +		mode = GT683R_LED_OFF;
> +
> +	gt683r_mode_set(led, mode);
> +fail:
> +	mutex_unlock(&led->lock);
> +}
> +
> +static DEVICE_ATTR_RW(mode);
> +
> +static int gt683r_led_probe(struct hid_device *hdev,
> +			const struct hid_device_id *id)
> +{
> +	int ret, i, name_sz;
> +	char *name;
> +	struct gt683r_led *led;
> +
> +	led = devm_kzalloc(&hdev->dev, sizeof(struct gt683r_led), GFP_KERNEL);
> +	if (!led)
> +		return -ENOMEM;
> +
> +	led->mode = GT683R_LED_NORMAL;
> +	led->hdev = hdev;
> +	hid_set_drvdata(hdev, led);
> +
> +	ret = hid_parse(hdev);
> +	if (ret) {
> +		hid_err(hdev, "hid parsing failed\n");
> +		goto fail;

Just return ret here.

> +	}
> +
> +	ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
> +	if (ret) {
> +		hid_err(hdev, "hw start failed\n");
> +		goto fail;
> +	}
> +
> +	for (i = 0; i < GT683R_LED_COUNT; i++) {
> +		name_sz = strlen(dev_name(&hdev->dev)) +
> +			strlen(gt683r_panel_names[i]) + 3;
> +
> +		name = devm_kzalloc(&hdev->dev, sizeof(char) * name_sz,
> +				GFP_KERNEL);

Must check for allocation failure still.

> +
> +		snprintf(name, name_sz, "%s::%s",
> +			dev_name(&hdev->dev), gt683r_panel_names[i]);
> +		led->led_devs[i].name = name;
> +		led->led_devs[i].max_brightness = 1;
> +		led->led_devs[i].brightness_set = gt683r_brightness_set;
> +		ret = led_classdev_register(&hdev->dev, &led->led_devs[i]);
> +		if (ret) {
> +			hid_err(hdev, "could not register led device\n");
> +			goto fail2;
> +		}
> +	}
> +
> +	ret = device_create_file(&led->hdev->dev,
> +				&dev_attr_mode);

No need to break line.

> +	if (ret) {
> +		hid_err(hdev, "could not make mode attribute file\n");
> +		goto fail2;
> +	}
> +
> +	mutex_init(&led->lock);
> +	INIT_WORK(&led->work, gt683r_led_work);
> +
> +	return 0;
> +
> +fail2:
> +	for (; i >= 0; i--)

You must initialise i to (i - 1) as well (either led_class_devregister
failed or i == GT683R_LED_COUNT here).

> +		led_classdev_unregister(&led->led_devs[i]);
> +	hid_hw_stop(hdev);
> +fail:
> +	return ret;
> +}
> +
> +static void gt683r_led_remove(struct hid_device *hdev)
> +{
> +	int i;
> +	struct gt683r_led *led = hid_get_drvdata(hdev);
> +
> +	for (i = 0; i < GT683R_LED_COUNT; i++)
> +		led_classdev_unregister(&led->led_devs[i]);
> +	device_remove_file(&hdev->dev,
> +			&dev_attr_mode);

No need to break line.

Perhaps do the removal before unregistering to reverse probe.

> +	flush_work(&led->work);
> +	hid_hw_stop(hdev);
> +}
> +
> +static struct hid_driver gt683r_led_driver = {
> +	.probe = gt683r_led_probe,
> +	.remove = gt683r_led_remove,
> +	.name = "gt683r_led",
> +	.id_table = gt683r_led_id,
> +};
> +
> +module_hid_driver(gt683r_led_driver);
> +
> +MODULE_AUTHOR("Janne Kanniainen");
> +MODULE_DESCRIPTION("MSI GT683R led driver");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
> index 34bb220..3692d37 100644
> --- a/drivers/hid/hid-ids.h
> +++ b/drivers/hid/hid-ids.h
> @@ -641,7 +641,7 @@
>  #define USB_DEVICE_ID_GENIUS_KB29E	0x3004
>  
>  #define USB_VENDOR_ID_MSI		0x1770
> -#define USB_DEVICE_ID_MSI_GX680R_LED_PANEL	0xff00
> +#define USB_DEVICE_ID_MSI_GT683R_LED_PANEL 0xff00
>  
>  #define USB_VENDOR_ID_NATIONAL_SEMICONDUCTOR 0x0400
>  #define USB_DEVICE_ID_N_S_HARMONY	0xc359
> diff --git a/drivers/hid/usbhid/hid-quirks.c b/drivers/hid/usbhid/hid-quirks.c
> index 8e4ddb3..c640e1d 100644
> --- a/drivers/hid/usbhid/hid-quirks.c
> +++ b/drivers/hid/usbhid/hid-quirks.c
> @@ -73,7 +73,7 @@ static const struct hid_blacklist {
>  	{ USB_VENDOR_ID_FORMOSA, USB_DEVICE_ID_FORMOSA_IR_RECEIVER, HID_QUIRK_NO_INIT_REPORTS },
>  	{ USB_VENDOR_ID_FREESCALE, USB_DEVICE_ID_FREESCALE_MX28, HID_QUIRK_NOGET },
>  	{ USB_VENDOR_ID_MGE, USB_DEVICE_ID_MGE_UPS, HID_QUIRK_NOGET },
> -	{ USB_VENDOR_ID_MSI, USB_DEVICE_ID_MSI_GX680R_LED_PANEL, HID_QUIRK_NO_INIT_REPORTS },
> +	{ USB_VENDOR_ID_MSI, USB_DEVICE_ID_MSI_GT683R_LED_PANEL, HID_QUIRK_NO_INIT_REPORTS },
>  	{ USB_VENDOR_ID_NEXIO, USB_DEVICE_ID_NEXIO_MULTITOUCH_PTI0750, HID_QUIRK_NO_INIT_REPORTS },
>  	{ USB_VENDOR_ID_NOVATEK, USB_DEVICE_ID_NOVATEK_MOUSE, HID_QUIRK_NO_INIT_REPORTS },
>  	{ USB_VENDOR_ID_PIXART, USB_DEVICE_ID_PIXART_OPTICAL_TOUCH_SCREEN, HID_QUIRK_NO_INIT_REPORTS },

Johan
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