Re: [PATCH 1/1] alix2: supplement driver to include GPIO button support

[Andres Salomon <dilinger@queued.net>]

On Fri,  6 Jan 2012 17:34:30 -0700
Philip Prindeville <philipp@redfish-solutions.com> wrote:

> From: "Philip A. Prindeville" <philipp@redfish-solutions.com>
> 
> GPIO 24 is used in reference designs as a soft-reset button, and
> the alix2 is no exception. Add it as a gpio-button.
> 
> Use symbolic values to describe BIOS addresses.
> 
> Record the model number.
> 
> Signed-off-by: Philip A. Prindeville <philipp@redfish-solutions.com>
> Acked-by: Ed Wildgoose <kernel@wildgooses.com>
> ---
>  arch/x86/platform/geode/alix.c |   53
> ++++++++++++++++++++++++++++++++++++---- 1 files changed, 48
> insertions(+), 5 deletions(-)
> 
> diff --git a/arch/x86/platform/geode/alix.c
> b/arch/x86/platform/geode/alix.c index dc5f1d3..a10476d42 100644
> --- a/arch/x86/platform/geode/alix.c
> +++ b/arch/x86/platform/geode/alix.c
> @@ -6,6 +6,7 @@
>   *
>   * Copyright (C) 2008 Constantin Baranov <const@mimas.ru>
>   * Copyright (C) 2011 Ed Wildgoose <kernel@wildgooses.com>
> + *                and Philip Prindeville
> <philipp@redfish-solutions.com> *
>   * TODO: There are large similarities with leds-net5501.c
>   * by Alessandro Zummo <a.zummo@towertech.it>
> @@ -24,14 +25,49 @@
>  #include <linux/leds.h>
>  #include <linux/platform_device.h>
>  #include <linux/gpio.h>
> +#include <linux/input.h>
> +#include <linux/gpio_keys.h>
>  
>  #include <asm/geode.h>
>  
> +#define BIOS_SIGNATURE_TINYBIOS		0x000f0000
> +#define BIOS_SIGNATURE_COREBOOT		0x00000050
> +#define BIOS_REGION_SIZE		0x00010000

No sense keeping the preceding 0s in those definitions; they just add
noise.

> +
> +static int model = 0;

The 0 assignment is unnecessary; 0 is the default.

> +
>  static bool force = 0;
>  module_param(force, bool, 0444);
>  /* FIXME: Award bios is not automatically detected as Alix platform
> */ MODULE_PARM_DESC(force, "Force detection as ALIX.2/ALIX.3
> platform"); 
> +static struct gpio_keys_button alix_gpio_buttons[] = {
> +	{
> +		.code = KEY_RESTART,
> +		.gpio = 24,
> +		.active_low = 1,
> +		.desc = "Reset button",
> +		.type = EV_KEY,
> +		.wakeup = 0,
> +		.debounce_interval = 100,
> +		.can_disable = 0,
> +	}
> +};
> +
> +static struct gpio_keys_platform_data alix_buttons_data = {
> +	.buttons = alix_gpio_buttons,
> +	.nbuttons = ARRAY_SIZE(alix_gpio_buttons),
> +	.poll_interval = 20,
> +};
> +
> +static struct platform_device alix_buttons_dev = {
> +	.name = "gpio-keys-polled",
> +	.id = 1,
> +	.dev = {
> +		.platform_data = &alix_buttons_data,
> +	}
> +};
> +
>  static struct gpio_led alix_leds[] = {
>  	{
>  		.name = "alix:1",
> @@ -64,17 +100,22 @@ static struct platform_device alix_leds_dev = {
>  	.dev.platform_data = &alix_leds_data,
>  };
>  
> +static struct __initdata platform_device *alix_devs[] = {
> +	&alix_buttons_dev,
> +	&alix_leds_dev,
> +};
> +
>  static void __init register_alix(void)
>  {
>  	/* Setup LED control through leds-gpio driver */
> -	platform_device_register(&alix_leds_dev);
> +	platform_add_devices(alix_devs, ARRAY_SIZE(alix_devs));
>  }
>  
>  static int __init alix_present(unsigned long bios_phys,
>  				const char *alix_sig,
>  				size_t alix_sig_len)
>  {
> -	const size_t bios_len = 0x00010000;
> +	const size_t bios_len = BIOS_REGION_SIZE;
>  	const char *bios_virt;
>  	const char *scan_end;
>  	const char *p;
> @@ -109,7 +150,9 @@ static int __init alix_present(unsigned long
> bios_phys, *a = '\0';
>  
>  		tail = p + alix_sig_len;
> -		if ((tail[0] == '2' || tail[0] == '3')) {
> +		if ((tail[0] == '2' || tail[0] == '3' || tail[0] ==
> '6')) {
> +			model = tail[0] - '0';

'model' is set here, but not used anywhere?

> +
>  			printk(KERN_INFO
>  			       "%s: system is recognized as
> \"%s\"\n", KBUILD_MODNAME, name);
> @@ -128,8 +171,8 @@ static int __init alix_init(void)
>  	if (!is_geode())
>  		return 0;
>  
> -	if (alix_present(0xf0000, tinybios_sig, sizeof(tinybios_sig)
> - 1) ||
> -	    alix_present(0x500, coreboot_sig, sizeof(coreboot_sig) -
> 1))

Hm, this is 0x500 here...


> +	if (alix_present(BIOS_SIGNATURE_TINYBIOS, tinybios_sig,
> sizeof(tinybios_sig) - 1) ||
> +	    alix_present(BIOS_SIGNATURE_COREBOOT, coreboot_sig,

But the definition above for SIGNATURE_COREBOOT is 0x50.  Is that a
typo?



> sizeof(coreboot_sig) - 1)) register_alix();
>  
>  	return 0;