Subject: [PATCH] ARM: OMAP2+: ads7846 init: fix fault caused by freeing pen-down GPIO

From: [email-masked] (Igor Grinberg)
Date: Fri, 27 Jul 2012 18:30:55 +0300

On 07/26/12 22:30, Kevin Hilman wrote:
> + Zumeng Chen
> 
> Igor Grinberg <[email-masked]> writes:
> 
>> Hi Kevin,
>>
>> I've just noticed that the patch has been modified by Arnd in a way
>> that of course will trigger GPIO use without being requested.
>> I'm sorry, I was not available by that time Arnd changed the patch.
> 
> Your right, your original patch isn't the problem.  I found the root
> cause.
> 
> The real problem is actually introduced by the merge of your patch from
> the arm-soc/cleanup branch, and this one from Zumeng Chen: commit
> 16aced80f6 (ARM: OMAP3530evm: set pendown_state and debounce time for
> ads7846) from the arm-soc/boards branch.
> 
> However, looking closer at the one from Zumeng, that one is clearly not
> right.  It unconditionally adds a *board-specific* ->get_pendown_state
> function to the pdata that is common to *all* boards.  That's just wrong
> and has the side-effect of making ->get_pendown_state() wrong on every
> board except the OMAP3EVM.  Oops.

Argh... that should not be applied in first place...
I double sorry, I was not available when that conflict was resolved...
The right resolution would be just to revert the 16aced80f6
(ARM: OMAP3530evm: set pendown_state and debounce time for ads7846),
but who cares now...

> 
> So, IMO, in addition to $SUBJECT patch, in order to get the touchscreen
> GPIO working on non OMAP3EVM boards, we also need something like this as
> well.
> 
> Igor, Zumeng, could you try this out on your boards anc confirm if it's
> working?  I currently don't have a board setup with a touchscreen in my
> board farm.

Since you have already dig into this, which branch would be good for testing?

> 
> Kevin
> 
>>>From 85516c6a3354967caf4cff434d28c3001cd411eb Mon Sep 17 00:00:00 2001
> From: Kevin Hilman <[email-masked]>
> Date: Thu, 26 Jul 2012 12:15:38 -0700
> Subject: [PATCH 2/2] ARM: OMAP2+: ads7846: fix ->get_pendown_state() to work
>  on all boards
> 
> commit 16aced80f6 (ARM: OMAP3530evm: set pendown_state and debounce
> time for ads7846) introduced a common ->get_pendown_state() function
> into the generic code, but that function was board-specific for the
> OMAP3EVM.
> 
> Fix this up to work for all boards that pass in a pendown GPIO.
> 
> Cc: Zumeng Chen <[email-masked]>
> Cc: Igor Grinberg <[email-masked]>
> Signed-off-by: Kevin Hilman <[email-masked]>
> ---
>  arch/arm/mach-omap2/board-omap3evm.c       |    1 +
>  arch/arm/mach-omap2/common-board-devices.c |    4 +++-
>  arch/arm/mach-omap2/common-board-devices.h |    1 -
>  3 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/mach-omap2/board-omap3evm.c b/arch/arm/mach-omap2/board-omap3evm.c
> index ef230a0..0d362e9 100644
> --- a/arch/arm/mach-omap2/board-omap3evm.c
> +++ b/arch/arm/mach-omap2/board-omap3evm.c
> @@ -58,6 +58,7 @@
>  #include "hsmmc.h"
>  #include "common-board-devices.h"
>  
> +#define OMAP3_EVM_TS_GPIO	175
>  #define OMAP3_EVM_EHCI_VBUS	22
>  #define OMAP3_EVM_EHCI_SELECT	61
>  
> diff --git a/arch/arm/mach-omap2/common-board-devices.c b/arch/arm/mach-omap2/common-board-devices.c
> index 0fee95f..06f176f 100644
> --- a/arch/arm/mach-omap2/common-board-devices.c
> +++ b/arch/arm/mach-omap2/common-board-devices.c
> @@ -40,9 +40,10 @@ static struct omap2_mcspi_device_config ads7846_mcspi_config = {
>   * of pdata->get_pendown_state, but we have done this. So set
>   * get_pendown_state to avoid twice gpio requesting.
>   */
> +static int omap3_gpio_pendown;
>  static int omap3_get_pendown_state(void)
>  {
> -	return !gpio_get_value(OMAP3_EVM_TS_GPIO);
> +	return !gpio_get_value(omap3_gpio_pendown);
>  }
>  
>  static struct ads7846_platform_data ads7846_config = {
> @@ -74,6 +75,7 @@ void __init omap_ads7846_init(int bus_num, int gpio_pendown, int gpio_debounce,
>  	struct spi_board_info *spi_bi = &ads7846_spi_board_info;
>  	int err;
>  
> +	omap3_gpio_pendown = gpio_pendown;
>  	err = gpio_request_one(gpio_pendown, GPIOF_IN, "TSPenDown");
>  	if (err) {
>  		pr_err("Couldn't obtain gpio for TSPenDown: %d\n", err);
> diff --git a/arch/arm/mach-omap2/common-board-devices.h b/arch/arm/mach-omap2/common-board-devices.h
> index 4c4ef6a..a0b4a428 100644
> --- a/arch/arm/mach-omap2/common-board-devices.h
> +++ b/arch/arm/mach-omap2/common-board-devices.h
> @@ -4,7 +4,6 @@
>  #include "twl-common.h"
>  
>  #define NAND_BLOCK_SIZE	SZ_128K
> -#define OMAP3_EVM_TS_GPIO	175
>  
>  struct mtd_partition;
>  struct ads7846_platform_data;

-- 
Regards,
Igor.