| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Fri, 08 Aug 2014 07:17:01 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Andreas Werner <andreas.werner@....de>
CC: Wim Van Sebroeck <wim@...ana.be>, Bryan Wu <cooloney@...il.com>,
lkml <linux-kernel@...r.kernel.org>,
Samuel Ortiz <sameo@...ux.intel.com>,
Lee Jones <lee.jones@...aro.org>,
"rpurdie@...ys.net" <rpurdie@...ys.net>,
Linux LED Subsystem <linux-leds@...r.kernel.org>,
linux-watchdog@...r.kernel.org
Subject: Re: [PATCH v3 3/3] drivers/leds/leds-menf21bmc: introduce MEN 14F021P00
BMC LED driver
On 08/08/2014 12:49 AM, Andreas Werner wrote:
> On Wed, Jul 30, 2014 at 06:57:46AM -0700, Guenter Roeck wrote:
>> On 07/30/2014 01:08 AM, Andreas Werner wrote:
>>> On Tue, Jul 29, 2014 at 02:47:08PM -0700, Guenter Roeck wrote:
>>>> On 07/29/2014 02:12 PM, Wim Van Sebroeck wrote:
>>>>> Hi Andreas,
>>>>>
>>>>>> aOn Thu, Jul 24, 2014 at 03:00:09PM -0700, Bryan Wu wrote:
>>>>>>> On Thu, Jul 17, 2014 at 6:18 AM, Andreas Werner <andreas.werner@....de> wrote:
>>>>>>>> Added driver to support the 14F021P00 BMC LEDs.
>>>>>>>> The BMC is a Board Management Controll include four LEDs which
>>>>>>>> can be switched on and off.
>>>>>>>>
>>>>>>>> This driver use the I2C interface to the BMC using the menf21bmc MFD Core driver.
>>>>>>>>
>>>>>>>> Signed-off-by: Andreas Werner <andreas.werner@....de>
>>>>>>>> ---
>>>>>>>> drivers/leds/Kconfig | 6 ++
>>>>>>>> drivers/leds/Makefile | 1 +
>>>>>>>> drivers/leds/leds-menf21bmc.c | 134 ++++++++++++++++++++++++++++++++++++++++++
>>>>>>>> 3 files changed, 141 insertions(+)
>>>>>>>> create mode 100644 drivers/leds/leds-menf21bmc.c
>>>>>>>>
>>>>>>>> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
>>>>>>>> index 27cf0cd..d38ff3f 100644
>>>>>>>> --- a/drivers/leds/Kconfig
>>>>>>>> +++ b/drivers/leds/Kconfig
>>>>>>>> @@ -458,6 +458,12 @@ config LEDS_OT200
>>>>>>>> This option enables support for the LEDs on the Bachmann OT200.
>>>>>>>> Say Y to enable LEDs on the Bachmann OT200.
>>>>>>>>
>>>>>>>> +config LEDS_MENF21BMC
>>>>>>>> + tristate "LED support for the MEN 14F021P00 BMC"
>>>>>>>> + depends on LEDS_CLASS && MFD_MENF21BMC
>>>>>>>
>>>>>>> I think it also depends on I2C.
>>>>>>
>>>>>> Yes you are right.
>>>>>>
>>>>>>>
>>>>>>>> + help
>>>>>>>> + Say Y here to include support for the MEN 14F021P00 BMC LEDs.
>>>>>>>> +
>>>>>>>> comment "LED driver for blink(1) USB RGB LED is under Special HID drivers (HID_THINGM)"
>>>>>>>>
>>>>>>>> config LEDS_BLINKM
>>>>>>>> diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
>>>>>>>> index 3c03666..cadc433 100644
>>>>>>>> --- a/drivers/leds/Makefile
>>>>>>>> +++ b/drivers/leds/Makefile
>>>>>>>> @@ -53,6 +53,7 @@ obj-$(CONFIG_LEDS_MAX8997) += leds-max8997.o
>>>>>>>> obj-$(CONFIG_LEDS_LM355x) += leds-lm355x.o
>>>>>>>> obj-$(CONFIG_LEDS_BLINKM) += leds-blinkm.o
>>>>>>>> obj-$(CONFIG_LEDS_VERSATILE) += leds-versatile.o
>>>>>>>> +obj-$(CONFIG_LEDS_MENF21BMC) += leds-menf21bmc.o
>>>>>>>>
>>>>>>>> # LED SPI Drivers
>>>>>>>> obj-$(CONFIG_LEDS_DAC124S085) += leds-dac124s085.o
>>>>>>>> diff --git a/drivers/leds/leds-menf21bmc.c b/drivers/leds/leds-menf21bmc.c
>>>>>>>> new file mode 100644
>>>>>>>> index 0000000..5eaa119
>>>>>>>> --- /dev/null
>>>>>>>> +++ b/drivers/leds/leds-menf21bmc.c
>>>>>>>> @@ -0,0 +1,134 @@
>>>>>>>> +/*
>>>>>>>> + * MEN 14F021P00 Board Management Controller (BMC) LEDs Driver.
>>>>>>>> + *
>>>>>>>> + * This is the core LED driver of the MEN 14F021P00 BMC.
>>>>>>>> + * There are four LEDs available which can be switched on and off.
>>>>>>>> + * STATUS LED, HOT SWAP LED, USER LED 1, USER LED 2
>>>>>>>> + *
>>>>>>>> + * Copyright (C) 2014 MEN Mikro Elektronik Nuernberg GmbH
>>>>>>>> + * Author: Andreas Werner <andreas.werner@....de>
>>>>>>>> + * All rights reserved.
>>>>>>>> + *
>>>>>>>> + * 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.
>>>>>>>> + *
>>>>>>>> + */
>>>>>>>> +
>>>>>>>> +#include <linux/module.h>
>>>>>>>> +#include <linux/kernel.h>
>>>>>>>> +#include <linux/platform_device.h>
>>>>>>>> +#include <linux/leds.h>
>>>>>>>> +#include <linux/i2c.h>
>>>>>>>> +
>>>>>>>> +#define BMC_CMD_LED_GET_SET 0xA0
>>>>>>>> +#define BMC_BIT_LED_STATUS BIT(0)
>>>>>>>> +#define BMC_BIT_LED_HOTSWAP BIT(1)
>>>>>>>> +#define BMC_BIT_LED_USER1 BIT(2)
>>>>>>>> +#define BMC_BIT_LED_USER2 BIT(3)
>>>>>>>> +
>>>>>>>> +struct menf21bmc_led {
>>>>>>>> + struct led_classdev cdev;
>>>>>>>> + u8 led_bit;
>>>>>>>> + const char *name;
>>>>>>>> + struct i2c_client *i2c_client;
>>>>>>>> +};
>>>>>>>> +
>>>>>>>> +static struct menf21bmc_led leds[] = {
>>>>>>>> + {
>>>>>>>> + .name = "menf21bmc:led_status",
>>>>>>>> + .led_bit = BMC_BIT_LED_STATUS,
>>>>>>>> + },
>>>>>>>> + {
>>>>>>>> + .name = "menf21bmc:led_hotswap",
>>>>>>>> + .led_bit = BMC_BIT_LED_HOTSWAP,
>>>>>>>> + },
>>>>>>>> + {
>>>>>>>> + .name = "menf21bmc:led_user1",
>>>>>>>> + .led_bit = BMC_BIT_LED_USER1,
>>>>>>>> + },
>>>>>>>> + {
>>>>>>>> + .name = "menf21bmc:led_user2",
>>>>>>>> + .led_bit = BMC_BIT_LED_USER2,
>>>>>>>> + }
>>>>>>>> +};
>>>>>>>> +
>>>>>>>> +static DEFINE_MUTEX(led_lock);
>>>>>>>> +
>>>>>>>> +static void
>>>>>>>> +menf21bmc_led_set(struct led_classdev *led_cdev, enum led_brightness value)
>>>>>>>> +{
>>>>>>>> + int led_val;
>>>>>>>> + struct menf21bmc_led *led = container_of(led_cdev,
>>>>>>>> + struct menf21bmc_led, cdev);
>>>>>>>> +
>>>>>>>> + mutex_lock(&led_lock);
>>>>>>>> + led_val = i2c_smbus_read_byte_data(led->i2c_client,
>>>>>>>> + BMC_CMD_LED_GET_SET);
>>>>>>>> + if (led_val < 0)
>>>>>>>> + goto err_out;
>>>>>>>> +
>>>>>>>> + if (value == LED_OFF)
>>>>>>>> + led_val &= ~led->led_bit;
>>>>>>>> + else
>>>>>>>> + led_val |= led->led_bit;
>>>>>>>> +
>>>>>>>> + i2c_smbus_write_byte_data(led->i2c_client,
>>>>>>>> + BMC_CMD_LED_GET_SET, led_val);
>>>>>>>> +err_out:
>>>>>>>> + mutex_unlock(&led_lock);
>>>>>>>> +}
>>>>>>>> +
>>>>>>>> +static int menf21bmc_led_probe(struct platform_device *pdev)
>>>>>>>> +{
>>>>>>>> + int i;
>>>>>>>> + int ret;
>>>>>>>> + struct i2c_client *i2c_client = to_i2c_client(pdev->dev.parent);
>>>>>>>> +
>>>>>>>> + for (i = 0; i < ARRAY_SIZE(leds); i++) {
>>>>>>>> + leds[i].cdev.name = leds[i].name;
>>>>>>>> + leds[i].cdev.brightness_set = menf21bmc_led_set;
>>>>>>>> + leds[i].i2c_client = i2c_client;
>>>>>>>> + ret = led_classdev_register(&pdev->dev, &leds[i].cdev);
>>>>>>>> + if (ret < 0)
>>>>>>>> + goto err_free_leds;
>>>>>>>> + }
>>>>>>>> + dev_info(&pdev->dev, "MEN 140F21P00 BMC LED device enabled\n");
>>>>>>>> +
>>>>>>>> + return 0;
>>>>>>>> +
>>>>>>>> +err_free_leds:
>>>>>>>> + dev_err(&pdev->dev, "failed to register LED device\n");
>>>>>>>> +
>>>>>>>> + for (i = i - 1; i >= 0; i--)
>>>>>>>> + led_classdev_unregister(&leds[i].cdev);
>>>>>>>> +
>>>>>>>> + return ret;
>>>>>>>> +}
>>>>>>>> +
>>>>>>>> +static int menf21bmc_led_remove(struct platform_device *pdev)
>>>>>>>> +{
>>>>>>>> + int i;
>>>>>>>> +
>>>>>>>> + for (i = 0; i < ARRAY_SIZE(leds); i++)
>>>>>>>> + led_classdev_unregister(&leds[i].cdev);
>>>>>>>> +
>>>>>>>> + return 0;
>>>>>>>> +}
>>>>>>>> +
>>>>>>>> +static struct platform_driver menf21bmc_led = {
>>>>>>>> + .probe = menf21bmc_led_probe,
>>>>>>>> + .remove = menf21bmc_led_remove,
>>>>>>>> + .driver = {
>>>>>>>> + .name = "menf21bmc_led",
>>>>>>>> + .owner = THIS_MODULE,
>>>>>>>> + },
>>>>>>>> +};
>>>>>>>> +
>>>>>>>
>>>>>>> This is not a normal platform driver, it should be a I2C driver.
>>>>>>>
>>>>>>>> +module_platform_driver(menf21bmc_led);
>>>>>>>
>>>>>>> So please move to use module_i2c_driver.
>>>>>>
>>>>>> Ok, but then I have to change that in the watchdog driver too, which
>>>>>> is quite the same as here.
>>>>>>
>>>>>> Lee, Guenther what do you think regarding the watchdog driver?
>>>>>
>>>>> If the watchdog part is indeed also i2c alike device then the watchdog part should also be an i2c driver...
>>>>>
>>>>
>>>> Isn't this all the same chip ? If so, there should be only one i2c driver.
>>>> Unless the i2c access is too complicated, it might make sense to use regmap
>>>> to access the chip, and pass the regmap pointer to the mfd slave drivers
>>>> to handle the actual communication with the chip.
>>>>
>>>> Guenter
>>>>
>>>
>>> Yes this is all the same chip which has different features like LEDs and Watchdog.
>>> This is why the mfd is the i2c_driver which instantiates the slave devices which
>>> are platform drivers.
>>>
>>> Is that not the normal way to handle those device?
>>> Is it really necessary to handle this to regmap?
>>>
>>
>> Not really sure if 'necessary' is the right term, it is just convenient.
>> Regmap takes care of register caching, for example, so you would not have to
>> re-read register values again and again from the chip just to modify a bit
>> of a register.
>> You can pass the regmap pointer in the platform data, or you can pass the
>> pointer to the i2c client. Using regmap makes the client driver independent
>> of the i2c subsystem. The one thing you can _not_ do is to declare the client
>> drivers to be i2c drivers.
>>
>> Guenter
>>
> I've checked out the regmap and it really sounds good.
> Before I will made those changes which is almost a complete replacement
> of the interface, i would like to know exactly why the slaves are no platform
> devices.
>
Did I say that ?
Guenter
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists