Re: [PATCH] applesmc: add sysfs file to report OSK

[Guenter Roeck]

On Mon, Dec 10, 2012 at 09:51:35AM -0500, Gabriel L. Somlo wrote:
> The AppleSMC contains two char[32] keys, OSK0 and OSK1, which are not
> reported in the key count and index by default. These keys are used by
> the OS X boot sequence, and normally don't matter when running Linux.
> 
> This patch creates a sysfs entry which reports the value of these keys
> as an ASCII string, to help emulators (such as QEMU) load OS X when
> running on genuine Apple hardware.
> 
> Signed-off-by: Gabriel L. Somlo <somlo@xxxxxxx>
> ---
> 
> For extra context: To boot OS X as a guest, QEMU must (among others)
> emulate the AppleSMC. To boot successfully, OS X insists on querying
> the (emulated) SMC for the value of OSK0 and OSK1. Currently, these
> values must be supplied on the QEMU command line as
> 
>   -device applesmc,osk="...concatenated values of OSK0 and OSK1..."
> 
> With the availability of /sys/devices/platform/applesmc.768/osk, the
> emulated QEMU AppleSMC could acquire this string directly from the
> (Apple-manufactured) host machine.
> 
Hmm ... this is a non-hwmon attribute which doesn't really belong into hwmon
in the first place ... like several other attributes in the same driver.

So I'll leave it up to the maintainer to decide if we should accept it. Henrik ?

Thanks,
Guenter

> Thanks,
>   Gabriel
> 
>  drivers/hwmon/applesmc.c |   18 ++++++++++++++++++
>  1 files changed, 18 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/hwmon/applesmc.c b/drivers/hwmon/applesmc.c
> index b41baff..0c7cc71 100644
> --- a/drivers/hwmon/applesmc.c
> +++ b/drivers/hwmon/applesmc.c
> @@ -1013,6 +1013,23 @@ static ssize_t applesmc_key_at_index_store(struct device *dev,
>  	return count;
>  }
>  
> +static ssize_t applesmc_osk_show(struct device *dev,
> +				struct device_attribute *attr, char *sysfsbuf)
> +{
> +	int fail;
> +
> +	mutex_lock(&smcreg.mutex);
> +	fail = read_smc(APPLESMC_READ_CMD, "OSK0", sysfsbuf, 32) ||
> +	       read_smc(APPLESMC_READ_CMD, "OSK1", sysfsbuf + 32, 32);
> +	mutex_unlock(&smcreg.mutex);
> +	if (fail)
> +		return -1;
> +
> +	sysfsbuf[64] = '\n';
> +	sysfsbuf[65] = '\0';
> +	return 65;
> +}
> +
>  static struct led_classdev applesmc_backlight = {
>  	.name			= "smc::kbd_backlight",
>  	.default_trigger	= "nand-disk",
> @@ -1027,6 +1044,7 @@ static struct applesmc_node_group info_group[] = {
>  	{ "key_at_index_type", applesmc_key_at_index_type_show },
>  	{ "key_at_index_data_length", applesmc_key_at_index_data_length_show },
>  	{ "key_at_index_data", applesmc_key_at_index_read_show },
> +	{ "osk", applesmc_osk_show },
>  	{ }
>  };
>  
> -- 
> 1.7.7.6
> 
> 
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