Re: [PATCH v4 3/4] drivers/leds/leds-menf21bmc: introduce MEN 14F021P00 BMC LED driver

[Guenter Roeck <linux@roeck-us.net>]

On Mon, Aug 25, 2014 at 11:53:32AM -0700, Bryan Wu wrote:
> On Wed, Aug 13, 2014 at 1:40 AM, Andreas Werner <andreas.werner@men.de> wrote:
> > Added driver to support the 14F021P00 BMC LEDs.
> > The BMC is a Board Management Controller including four LEDs which
> > can be switched on and off.
> >
> > Signed-off-by: Andreas Werner <andreas.werner@men.de>
> > ---
> >  drivers/leds/Kconfig          |   6 ++
> >  drivers/leds/Makefile         |   1 +
> >  drivers/leds/leds-menf21bmc.c | 131 ++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 138 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
> > +       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..4621f72
> > --- /dev/null
> > +++ b/drivers/leds/leds-menf21bmc.c
> > @@ -0,0 +1,131 @@
> > +/*
> > + *  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
> > + *
> > + *  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,
> > +       },
> > +};
> > +
> 
> I still think this driver should be an I2C driver which is simply than
> a platform driver.
> Did I miss some discussion about this in our email?
> 
It is not possible to instantiate multiple drivers (watchdog, hwmon, led
in this case) with a single i2c chip.

Thanks,
Guenter