Re: [PATCH v5] extcon-axp288: Add axp288 extcon driver support

[Lee Jones <lee.jones@linaro.org>]

On Tue, 28 Apr 2015, Pallala, Ramakrishna wrote:

> > > This patch adds the extcon support for AXP288 PMIC which has the BC1.2
> > > charger detection capability. Additionally it also adds the USB mux
> > > switching support b/w SOC and PMIC based on GPIO control.
> > >
> > > Signed-off-by: Ramakrishna Pallala <ramakrishna.pallala@intel.com>
> > > ---
> > >  drivers/extcon/Kconfig         |    7 +
> > >  drivers/extcon/Makefile        |    1 +
> > >  drivers/extcon/extcon-axp288.c |  399
> > ++++++++++++++++++++++++++++++++++++++++
> > >  include/linux/mfd/axp20x.h     |    9 +
> > >  4 files changed, 416 insertions(+)
> > >  create mode 100644 drivers/extcon/extcon-axp288.c
> > >
> > > diff --git a/drivers/extcon/Kconfig b/drivers/extcon/Kconfig index
> > > fdc0bf0..2305edc 100644
> > > --- a/drivers/extcon/Kconfig
> > > +++ b/drivers/extcon/Kconfig
> > > @@ -28,6 +28,13 @@ config EXTCON_ARIZONA
> > >  	  with Wolfson Arizona devices. These are audio CODECs with
> > >  	  advanced audio accessory detection support.
> > >
> > > +config EXTCON_AXP288
> > > +	tristate "X-Power AXP288 EXTCON support"
> > > +	depends on MFD_AXP20X && USB_PHY
> > > +	help
> > > +	  Say Y here to enable support for USB peripheral detection
> > > +	  and USB MUX switching by X-Power AXP288 PMIC.
> > > +
> > >  config EXTCON_GPIO
> > >  	tristate "GPIO extcon support"
> > >  	depends on GPIOLIB
> > > diff --git a/drivers/extcon/Makefile b/drivers/extcon/Makefile index
> > > 9204114..ba787d0 100644
> > > --- a/drivers/extcon/Makefile
> > > +++ b/drivers/extcon/Makefile
> > > @@ -5,6 +5,7 @@
> > >  obj-$(CONFIG_EXTCON)		+= extcon.o
> > >  obj-$(CONFIG_EXTCON_ADC_JACK)	+= extcon-adc-jack.o
> > >  obj-$(CONFIG_EXTCON_ARIZONA)	+= extcon-arizona.o
> > > +obj-$(CONFIG_EXTCON_AXP288)	+= extcon-axp288.o
> > >  obj-$(CONFIG_EXTCON_GPIO)	+= extcon-gpio.o
> > >  obj-$(CONFIG_EXTCON_MAX14577)	+= extcon-max14577.o
> > >  obj-$(CONFIG_EXTCON_MAX77693)	+= extcon-max77693.o
> > > diff --git a/drivers/extcon/extcon-axp288.c
> > > b/drivers/extcon/extcon-axp288.c new file mode 100644 index
> > > 0000000..91d764c
> > > --- /dev/null
> > > +++ b/drivers/extcon/extcon-axp288.c
> > > @@ -0,0 +1,399 @@
> > > +/*
> > > + * extcon-axp288.c - X-Power AXP288 PMIC extcon cable detection
> > > +driver
> > > + *
> > > + * Copyright (C) 2014 Intel Corporation
> > > + * Author: Ramakrishna Pallala <ramakrishna.pallala@intel.com>
> > > + *
> > > + * This program is free software; you can redistribute it and/or
> > > +modify
> > > + * it under the terms of the GNU General Public License version 2 as
> > > + * published by the Free Software Foundation.
> > > + *
> > > + * 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/module.h>
> > > +#include <linux/kernel.h>
> > > +#include <linux/io.h>
> > > +#include <linux/slab.h>
> > > +#include <linux/interrupt.h>
> > > +#include <linux/platform_device.h>
> > > +#include <linux/property.h>
> > > +#include <linux/usb/phy.h>
> > > +#include <linux/notifier.h>
> > > +#include <linux/extcon.h>
> > > +#include <linux/regmap.h>
> > > +#include <linux/gpio.h>
> > > +#include <linux/gpio/consumer.h>
> > > +#include <linux/mfd/axp20x.h>
> 
> [snip]
> 
> > > +module_platform_driver(axp288_extcon_driver);
> > > +
> > > +MODULE_AUTHOR("Ramakrishna Pallala <ramakrishna.pallala@intel.com>");
> > > +MODULE_DESCRIPTION("X-Powers AXP288 extcon driver");
> > > +MODULE_LICENSE("GPL v2");
> > > diff --git a/include/linux/mfd/axp20x.h b/include/linux/mfd/axp20x.h
> > > index dfabd6d..81152e2 100644
> > > --- a/include/linux/mfd/axp20x.h
> > > +++ b/include/linux/mfd/axp20x.h
> > > @@ -275,4 +275,13 @@ struct axp20x_fg_pdata {
> > >  	int thermistor_curve[MAX_THERM_CURVE_SIZE][2];
> > >  };
> > >
> > > +#define AXP288_EXTCON_CABLE_SDP		"SLOW-CHARGER"
> > > +#define AXP288_EXTCON_CABLE_CDP		"CHARGE-
> > DOWNSTREAM"
> > > +#define AXP288_EXTCON_CABLE_DCP		"FAST-CHARGER"
> > 
> > #defines are meant to make things *easier* for humans to read. It is my opinion
> > that these negatively impact the readability of the code.
> These macros will be used in extcon and charger drivers. How can I make it more readable?

If the things you're defining are more readable than the defines
themselves you're doing the opposite of what I'd expect.

How about:

  AXP288_EXTCON_SLOW_CHARGER_CABLE
  AXP288_EXTCON_FAST_CHARGER_CABLE
  AXP288_EXTCON_CHARGE_DOWNSTREAM_CABLE

> > > +struct axp288_extcon_pdata {
> > > +	/* GPIO pin control to switch D+/D- lines b/w PMIC and SOC */
> > > +	struct gpio_desc *gpio_mux_cntl;
> > > +};
> > 
> > Are you going to add to this?
> Yes, this is needed.
> 
> Thanks,
> Ram

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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