On Monday, January 14, 2013 04:46:28 PM Mika Westerberg wrote:
> Since we don't want to create the Lynxpoint LPSS clock tree on a machines
> where no LPSS exists at all we look for the Lynxpoint device ACPI HIDs
> during ACPI namespace scan and if a known device is seen we assume that it
> is safe to create the LPSS clocks.
>
> Therefore we allow init function to be passed via acpi_platform_device_ids[]
> table which is called whenever the corresponding device is found.
>
> Signed-off-by: Mika Westerberg <mika.westerb...@linux.intel.com>
> ---
> drivers/acpi/scan.c | 36 +++++++++++++++++++++++++++---------
> 1 file changed, 27 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> index 6a12702..8d9965e 100644
> --- a/drivers/acpi/scan.c
> +++ b/drivers/acpi/scan.c
> @@ -11,6 +11,7 @@
> #include <linux/kthread.h>
> #include <linux/dmi.h>
> #include <linux/nls.h>
> +#include <linux/platform_device.h>
>
> #include <acpi/acpi_drivers.h>
>
> @@ -29,6 +30,15 @@ extern struct acpi_device *acpi_root;
>
> static const char *dummy_hid = "device";
>
> +static void lpt_lpss_init_once(void)
> +{
> + static struct platform_device *pdev;
> +
> + /* Lynxpoint LPSS clocks */
> + if (!pdev)
> + pdev = platform_device_register_simple("clk-lpt", -1, NULL, 0);
> +}
> +
> /*
> * The following ACPI IDs are known to be suitable for representing as
> * platform devices.
> @@ -38,14 +48,14 @@ static const struct acpi_device_id
> acpi_platform_device_ids[] = {
> { "PNP0D40" },
>
> /* Haswell LPSS devices */
> - { "INT33C0", 0 },
> - { "INT33C1", 0 },
> - { "INT33C2", 0 },
> - { "INT33C3", 0 },
> - { "INT33C4", 0 },
> - { "INT33C5", 0 },
> - { "INT33C6", 0 },
> - { "INT33C7", 0 },
> + { "INT33C0", (kernel_ulong_t)lpt_lpss_init_once },
> + { "INT33C1", (kernel_ulong_t)lpt_lpss_init_once },
> + { "INT33C2", (kernel_ulong_t)lpt_lpss_init_once },
> + { "INT33C3", (kernel_ulong_t)lpt_lpss_init_once },
> + { "INT33C4", (kernel_ulong_t)lpt_lpss_init_once },
> + { "INT33C5", (kernel_ulong_t)lpt_lpss_init_once },
> + { "INT33C6", (kernel_ulong_t)lpt_lpss_init_once },
> + { "INT33C7", (kernel_ulong_t)lpt_lpss_init_once },
>
> { }
> };
> @@ -1580,6 +1590,7 @@ static acpi_status acpi_bus_check_add(acpi_handle
> handle, u32 lvl_not_used,
> static acpi_status acpi_bus_device_attach(acpi_handle handle, u32
> lvl_not_used,
> void *not_used, void **ret_not_used)
> {
> + const struct acpi_device_id *id;
> acpi_status status = AE_OK;
> struct acpi_device *device;
> unsigned long long sta_not_used;
> @@ -1595,7 +1606,14 @@ static acpi_status acpi_bus_device_attach(acpi_handle
> handle, u32 lvl_not_used,
> if (acpi_bus_get_device(handle, &device))
> return AE_CTRL_DEPTH;
>
> - if (!acpi_match_device_ids(device, acpi_platform_device_ids)) {
> + id = __acpi_match_device(device, acpi_platform_device_ids);
> + if (id) {
> + void (*init)(void) = (void (*)(void))id->driver_data;
> +
> + /* Run any initialization if required */
> + if (init)
> + init();
> +
I'd prefer this to be done by acpi_create_platform_device() and you can add
an extra arg to it for this purpose.
Moreover the driver_data need not be a function pointer. I actually think it
should consist of a number of flags that may be set or unset and the 0 bit
could be ACPI_PLATFORM_CLK or something like this. Then, if that is set in
its (new) second arg, acpi_create_platform_device() will do the
platform_device_register_simple("clk-lpt", ...), if not done already.
And yes, we may need those flags for other stuff.
> /* This is a known good platform device. */
> acpi_create_platform_device(device);
> } else if (device_attach(&device->dev) < 0) {
>
Thanks,
Rafael
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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