RE: [PATCH 0/4 RFC]OMAP:GPIO: Make GPIO an early init device

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Tony, 

> > > >
> > > > http://www.pwsan.com/omap/patches/gpio/0002-OMAP-GPIO-split-omap1-and-
> > > omap2.patch
> > >
> > > What, make two almost identical copies of the shared code? No way!
> > > Instead, please keep the common code under plat-omap:
> > >
> > > arch/arm/plat-omap/gpio.c
> > >
> > > Then implement the processor specific functions:
> > >
> > > arch/arm/mach-omap1/gpio.c
> > > arch/arm/mach-omap2/gpio.c
> > > arch/arm/mach-omap2/gpio24xx.c
> > > arch/arm/mach-omap2/gpio44xx.c
> > >
> > > Then have a subsys_initcall in processor specific implementation
> > > that sets the function pointers in the common code.
> > >
> > Tony,
> >
> > The current gpio.c has functions with code similar as mentioned below:
> > {
> > 	#ifdef CONFIG_ARCH_OMAP1
> > 		Get the reg offset for OMAP1
> > 	#endif
> > 	#ifdef CONFIG_ARCH_OMAP15XX
> > 		Get the reg offset for OMAP15XX
> > 	#endif
> > 	#ifdef CONFIG_ARCH_OMAP16XX
> > 		Get the reg offset for OMAP16XX
> > 	#endif
> > 	#if defined(CONFIG_ARCH_OMAP730) || defined(CONFIG_ARCH_OMAP850)
> > 		Get the reg offset for this OMAP
> > 	#endif
> > 	#if defined(CONFIG_ARCH_OMAP2) || defined(CONFIG_ARCH_OMAP3)
> > 		Get the reg offset for OMAP2&3
> > 	#endif
> > 	#if defined(CONFIG_ARCH_OMAP4)
> > 		Get the reg offset for OMAP4
> > 	#endif
> >
> > 	Read/write the register
> > }
> >
> > If function pointers are used in common code (plat-omap/gpio.c), the API's in
> this file would essentially do nothing but invoke these pointers. IMHO this is
> simply adding one unnecessary level of indirection.
> > Please correct me if I am missing out something.
> 
> For those you can just set the various reg offsets once
> during __init based on the omap type and then the function
> stays the same.
> 
> For example, in arch/arm/mach-omap2/gpio44xx.c you could
> have something like the following (completely untested):
> 
> static const struct gpio_reg omap4_gpio_reg[] = {
> 	...
> };
> 
> static const struct gpio_bank omap4_gpio_bank[] = {
> 	...
> };
> 
> static int omap_gpio_suspend(struct sys_device *dev, pm_message_t mesg)
> {
> 	...
> }
> 
> static int omap_gpio_resume(struct sys_device *dev)
> {
> 	...
> }
> 
> const struct omap_gpio omap4_gpio = {
> 	.regs		= omap4_gpio_reg,
> 	.banks		= omap4_gpio_bank,
> 	.suspend	= omap4_gpio_suspend,
> 	.resume		= omap4_gpio_resume,
> 	...
> };
> 
> ...
> 
> static int __init omap_gpio_init(void)
> {
> 	if (!cpu_is_omap44xx())
> 		return -ENODEV;
> 
> 	return omap_gpio_init(omap4_gpio);
> }
> arch_initcall(omap44xx_gpio_init);
> 
> For some of them, you want to be able to implement the whole
> function depending on the omap type that you boot.
> 
> We're already doing it like this in most places, the gpio.c code
> just needs to be updated for that.

Thanks. Can you please specify some example code & location in the 
current code base, so that I can align exactly before sending my
next version of patches? 

> 
> Regards,
> 
> Tony

--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[Index of Archives]     [Linux Arm (vger)]     [ARM Kernel]     [ARM MSM]     [Linux Tegra]     [Linux WPAN Networking]     [Linux Wireless Networking]     [Maemo Users]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Trails]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux