Subject: [PATCH 1/2] ARM: SAMSUNG: Insert bitmap_gpio_int member in samsung_gpio_chip

From: [email-masked] (Eunki Kim)
Date: Fri, 28 Sep 2012 11:41:02 +0900

> -----Original Message-----
> From: Joonyoung Shim [mailto:jy0922.shim at samsung.com]
> Sent: Thursday, September 27, 2012 4:42 PM
> To: Eunki Kim
> Cc: linux-arm-kernel at lists.infradead.org; linux-samsung-soc at vger.kernel.org;
> grant.likely at secretlab.ca; linus.walleij at linaro.org; kgene.kim at samsung.com
> Subject: Re: [PATCH 1/2] ARM: SAMSUNG: Insert bitmap_gpio_int member in samsung_gpio_chip
> 
> On 09/27/2012 02:55 PM, Eunki Kim wrote:
> >> -----Original Message-----
> >> From: Joonyoung Shim [mailto:jy0922.shim at samsung.com]
> >> Sent: Thursday, September 27, 2012 1:50 PM
> >> To: Eunki Kim
> >> Cc: linux-arm-kernel at lists.infradead.org;
> >> linux-samsung-soc at vger.kernel.org;
> >> grant.likely at secretlab.ca; linus.walleij at linaro.org;
> >> kgene.kim at samsung.com
> >> Subject: Re: [PATCH 1/2] ARM: SAMSUNG: Insert bitmap_gpio_int member
> >> in samsung_gpio_chip
> >>
> >> On 09/27/2012 12:55 PM, Eunki Kim wrote:
> >>> When a device uses GPIO interrupt, its driver assumes that GPIO
> >>> should be INPUT mode. However, GPIO of SAMSUNG SoC is sepated to
> >>> INPUT mode and INTERRUPT mode. They are set by 0x0 and 0xF in GPIO
> >>> control register. If the register is set to INPUT mode, the
> >>> interrupt never occur. Therefore, it's necessary to set INTERRUPT
> >>> mode instead of INPUT mode when the pin is used for GPIO interrupt.
> >> If for this, already the patch was posted.
> >>
> >> http://lists.infradead.org/pipermail/linux-arm-kernel/2011-November/0
> >> 74387.html
> >>
> >> Thanks.
> >>
> > The old posted patch and my new patches solve the same problem.
> >
> > However, the old patch fixes s5p_gpioint_set_type function which is
> > irq_set_type function of GPIO int. The objective of irq_set_type function is setting IRQ type as
> rising, falling, level and etc.
> > It's not setting GPIO pin configuration.
> 
> Ok, it's reasonable but s5p_irq_eint_set_type() does it. So, do we need to remove it in
> s5p_irq_eint_set_type() later?
> 

What do you mean? The old patch was not merged to mainline. I have checked 3.6-rc7 kernel source,
but there isn't.

> >
> > The new patches solve the problem root. It monitors use of GPIO int
> > for each pin. If then, it sets INTERRUPT mode instead of INPUT mode
> > when gpio_direction_input function is called. As you know, the objective of gpio_direction_input
> function is setting the GPIO configuration.
> 
> Ok. It is minor concern, we will have to take care of the function call order dependency because
> s5p_register_gpio_interrupt() should be called prior to gpio_direction_input().
> 
> Thanks.
> 

The s5p_register_gpio_interrupt function is called from the board file like mach-nuri.c
mach-universal_c210.c. mach-goni.c generally. And also, setting GPIO pin to INTERRUPT mode codes
(ex: s3c_gpio_cfgpin(gpio, S3C_GPIO_SFN(0xf));) follow the s5p_register_gpio_interrupt function.
It's better to remain setting INTERRUPT mode. This patch just prevents from changing to INPUT mode
by gpio_direction_input in any driver's probe function.

Thanks.

> >
> >>> This patch inserts the bitmap_gpio_int member in struct samsung_
> >>> gpio_chip in order to represent use of GPIO interrupt for each pin
> >>> and sets the related bit when s5p_register_gpio_interrupt function
> >>> is called.
> >>>
> >>> Signed-off-by: Eunki Kim <[email-masked]>
> >>> Cc: Grant Likely <[email-masked]>
> >>> Cc: Linus Walleij <[email-masked]>
> >>> ---
> >>>    arch/arm/plat-samsung/include/plat/gpio-core.h |    2 ++
> >>>    arch/arm/plat-samsung/s5p-irq-gpioint.c        |    8 ++++++--
> >>>    2 files changed, 8 insertions(+), 2 deletions(-)
> >>>
> >>> diff --git a/arch/arm/plat-samsung/include/plat/gpio-core.h
> >>> b/arch/arm/plat-samsung/include/plat/gpio-core.h
> >>> index 1fe6917..dfd8b7a 100644
> >>> --- a/arch/arm/plat-samsung/include/plat/gpio-core.h
> >>> +++ b/arch/arm/plat-samsung/include/plat/gpio-core.h
> >>> @@ -48,6 +48,7 @@ struct samsung_gpio_cfg;
> >>>     * @config: special function and pull-resistor control information.
> >>>     * @lock: Lock for exclusive access to this gpio bank.
> >>>     * @pm_save: Save information for suspend/resume support.
> >>> + * @bitmap_gpio_int: Bitmap for representing GPIO interrupt or not.
> >>>     *
> >>>     * This wrapper provides the necessary information for the Samsung
> >>>     * specific gpios being registered with gpiolib.
> >>> @@ -71,6 +72,7 @@ struct samsung_gpio_chip {
> >>>    #ifdef CONFIG_PM
> >>>    	u32			pm_save[4];
> >>>    #endif
> >>> +	u32			bitmap_gpio_int;
> >>>    };
> >>>
> >>>    static inline struct samsung_gpio_chip *to_samsung_gpio(struct
> >>> gpio_chip *gpc) diff --git a/arch/arm/plat-samsung/s5p-irq-gpioint.c
> >>> b/arch/arm/plat-samsung/s5p-irq-gpioint.c
> >>> index f9431fe..d981c61 100644
> >>> --- a/arch/arm/plat-samsung/s5p-irq-gpioint.c
> >>> +++ b/arch/arm/plat-samsung/s5p-irq-gpioint.c
> >>> @@ -185,7 +185,7 @@ int __init s5p_register_gpio_interrupt(int pin)
> >>>
> >>>    	/* check if the group has been already registered */
> >>>    	if (my_chip->irq_base)
> >>> -		return my_chip->irq_base + offset;
> >>> +		goto success;
> >>>
> >>>    	/* register gpio group */
> >>>    	ret = s5p_gpioint_add(my_chip);
> >>> @@ -193,9 +193,13 @@ int __init s5p_register_gpio_interrupt(int pin)
> >>>    		my_chip->chip.to_irq = samsung_gpiolib_to_irq;
> >>>    		printk(KERN_INFO "Registered interrupt support for gpio group %d.\n",
> >>>    		       group);
> >>> -		return my_chip->irq_base + offset;
> >>> +		goto success;
> >>>    	}
> >>>    	return ret;
> >>> +success:
> >>> +	my_chip->bitmap_gpio_int |= BIT(offset);
> >>> +
> >>> +	return my_chip->irq_base + offset;
> >>>    }
> >>>
> >>>    int __init s5p_register_gpioint_bank(int chain_irq, int start,
> >>> int
> >>> nr_groups)
> >