Re: [PATCH 1/7] USB: add devicetree helpers for determining dr_mode and phy_type

[Michael Grzeschik <mgr-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>]

On Mon, Jun 03, 2013 at 03:32:50PM +0300, Alexander Shishkin wrote:
> Michael Grzeschik <mgr-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> writes:
> 
> > From: Michael Grzeschik <m.grzeschik-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
> >
> > This adds two little devicetree helper functions for determining the
> > dr_mode (host, peripheral, otg) and phy_type (utmi, ulpi,...) from
> > the devicetree.
> 
> This one needs an ack from Felipe.

Right, we currently also wait for his answer in another thread.

http://www.spinics.net/lists/linux-usb/msg86906.html

> > Signed-off-by: Michael Grzeschik <m.grzeschik-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
> > Signed-off-by: Marc Kleine-Budde <mkl-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
> > Signed-off-by: Sascha Hauer <s.hauer-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
> > ---
> >  drivers/usb/phy/Makefile |  1 +
> >  drivers/usb/phy/of.c     | 47 +++++++++++++++++++++++++++++++++++++++++++++++
> >  drivers/usb/usb-common.c | 35 +++++++++++++++++++++++++++++++++++
> >  include/linux/usb/of.h   | 28 ++++++++++++++++++++++++++++
> >  include/linux/usb/otg.h  |  7 +++++++
> >  include/linux/usb/phy.h  |  9 +++++++++
> >  6 files changed, 127 insertions(+)
> >  create mode 100644 drivers/usb/phy/of.c
> >  create mode 100644 include/linux/usb/of.h
> >
> > diff --git a/drivers/usb/phy/Makefile b/drivers/usb/phy/Makefile
> > index a9169cb..070eca3 100644
> > --- a/drivers/usb/phy/Makefile
> > +++ b/drivers/usb/phy/Makefile
> > @@ -5,6 +5,7 @@
> >  ccflags-$(CONFIG_USB_DEBUG) := -DDEBUG
> >  
> >  obj-$(CONFIG_USB_PHY)			+= phy.o
> > +obj-$(CONFIG_OF)			+= of.o
> >  
> >  # transceiver drivers, keep the list sorted
> >  
> > diff --git a/drivers/usb/phy/of.c b/drivers/usb/phy/of.c
> > new file mode 100644
> > index 0000000..e6f3b74
> > --- /dev/null
> > +++ b/drivers/usb/phy/of.c
> > @@ -0,0 +1,47 @@
> > +/*
> > + * USB of helper code
> > + *
> > + * 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/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/usb/of.h>
> > +#include <linux/usb/otg.h>
> > +
> > +static const char *usbphy_modes[] = {
> > +	[USBPHY_INTERFACE_MODE_UNKNOWN]	= "",
> > +	[USBPHY_INTERFACE_MODE_UTMI]	= "utmi",
> > +	[USBPHY_INTERFACE_MODE_UTMIW]	= "utmi_wide",
> > +	[USBPHY_INTERFACE_MODE_ULPI]	= "ulpi",
> > +	[USBPHY_INTERFACE_MODE_SERIAL]	= "serial",
> > +	[USBPHY_INTERFACE_MODE_HSIC]	= "hsic",
> > +};
> > +
> > +/**
> > + * of_usb_get_phy_mode - Get phy mode for given device_node
> > + * @np:	Pointer to the given device_node
> > + *
> > + * The function gets phy interface string from property 'phy_type',
> > + * and returns the correspondig enum usb_phy_interface
> > + */
> > +enum usb_phy_interface of_usb_get_phy_mode(struct device_node *np)
> > +{
> > +	const char *phy_type;
> > +	int err, i;
> > +
> > +	err = of_property_read_string(np, "phy_type", &phy_type);
> > +	if (err < 0)
> > +		return USBPHY_INTERFACE_MODE_UNKNOWN;
> > +
> > +	for (i = 0; i < ARRAY_SIZE(usbphy_modes); i++)
> > +		if (!strcmp(phy_type, usbphy_modes[i]))
> > +			return i;
> > +
> > +	return USBPHY_INTERFACE_MODE_UNKNOWN;
> > +}
> > +EXPORT_SYMBOL_GPL(of_usb_get_phy_mode);
> > diff --git a/drivers/usb/usb-common.c b/drivers/usb/usb-common.c
> > index 0db0a91..027582d 100644
> > --- a/drivers/usb/usb-common.c
> > +++ b/drivers/usb/usb-common.c
> > @@ -13,7 +13,9 @@
> >  
> >  #include <linux/kernel.h>
> >  #include <linux/module.h>
> > +#include <linux/of.h>
> >  #include <linux/usb/ch9.h>
> > +#include <linux/usb/of.h>
> >  #include <linux/usb/otg.h>
> >  
> >  const char *usb_otg_state_string(enum usb_otg_state state)
> > @@ -79,4 +81,37 @@ const char *usb_state_string(enum usb_device_state state)
> >  }
> >  EXPORT_SYMBOL_GPL(usb_state_string);
> >  
> > +#ifdef CONFIG_OF
> > +static const char *usb_dr_modes[] = {
> > +	[USB_DR_MODE_UNKNOWN]		= "",
> > +	[USB_DR_MODE_HOST]		= "host",
> > +	[USB_DR_MODE_PERIPHERAL]	= "peripheral",
> > +	[USB_DR_MODE_OTG]		= "otg",
> > +};
> > +
> > +/**
> > + * of_usb_get_dr_mode - Get dual role mode for given device_node
> > + * @np:	Pointer to the given device_node
> > + *
> > + * The function gets phy interface string from property 'dr_mode',
> > + * and returns the correspondig enum usb_dr_mode
> > + */
> > +enum usb_dr_mode of_usb_get_dr_mode(struct device_node *np)
> > +{
> > +	const char *dr_mode;
> > +	int err, i;
> > +
> > +	err = of_property_read_string(np, "dr_mode", &dr_mode);
> > +	if (err < 0)
> > +		return USB_DR_MODE_UNKNOWN;
> > +
> > +	for (i = 0; i < ARRAY_SIZE(usb_dr_modes); i++)
> > +		if (!strcmp(dr_mode, usb_dr_modes[i]))
> > +			return i;
> > +
> > +	return USB_DR_MODE_UNKNOWN;
> > +}
> > +EXPORT_SYMBOL_GPL(of_usb_get_dr_mode);
> > +#endif
> > +
> >  MODULE_LICENSE("GPL");
> > diff --git a/include/linux/usb/of.h b/include/linux/usb/of.h
> > new file mode 100644
> > index 0000000..e460a24
> > --- /dev/null
> > +++ b/include/linux/usb/of.h
> > @@ -0,0 +1,28 @@
> > +/*
> > + * OF helpers for usb devices.
> > + *
> > + * This file is released under the GPLv2
> > + */
> > +
> > +#ifndef __LINUX_USB_OF_H
> > +#define __LINUX_USB_OF_H
> > +
> > +#include <linux/usb/otg.h>
> > +#include <linux/usb/phy.h>
> > +
> > +#ifdef CONFIG_OF
> > +enum usb_phy_interface of_usb_get_phy_mode(struct device_node *np);
> > +enum usb_dr_mode of_usb_get_dr_mode(struct device_node *np);
> > +#else
> > +static inline enum usb_phy_interface of_usb_get_phy_mode(struct device_node *np)
> > +{
> > +	return USBPHY_INTERFACE_MODE_UNKNOWN;
> > +}
> > +
> > +static inline enum usb_dr_mode of_usb_get_dr_mode(struct device_node *np)
> > +{
> > +	return USB_DR_MODE_UNKNOWN;
> > +}
> > +#endif
> > +
> > +#endif /* __LINUX_USB_OF_H */
> > diff --git a/include/linux/usb/otg.h b/include/linux/usb/otg.h
> > index 291e01b..154332b 100644
> > --- a/include/linux/usb/otg.h
> > +++ b/include/linux/usb/otg.h
> > @@ -92,4 +92,11 @@ otg_start_srp(struct usb_otg *otg)
> >  /* for OTG controller drivers (and maybe other stuff) */
> >  extern int usb_bus_start_enum(struct usb_bus *bus, unsigned port_num);
> >  
> > +enum usb_dr_mode {
> > +	USB_DR_MODE_UNKNOWN,
> > +	USB_DR_MODE_HOST,
> > +	USB_DR_MODE_PERIPHERAL,
> > +	USB_DR_MODE_OTG,
> > +};
> > +
> 
> I would suggest turning this into a bitmask, so that further tests look
> like
> 
>   if (dr_mode & USB_DR_MODE_HOST) {...}
>
> instead of how they currently look like in the other patch.

You mean 32 modes will be enough? :)

These helpers are derived from drivers/of/of_net.c. Its enums are
commonly used all over the kernel. We should align to already used
coding patterns. I also prefer to switch over an enum than compare bits.

Thanks,
Michael

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