Re: [PATCH V6 07/11] ACPI: introduce dummy lpss scan handler

[Mika Westerberg <mika.westerberg@linux.intel.com>]

On Thu, May 15, 2014 at 02:44:12PM +0800, Zhang Rui wrote:
> The new ACPI device enumeration mechanism, which will be introduced
> in a later patch, will enumerate the _HID devices w/o any scan
> handler attached to platform bus.
> This means that, for the devices that are attached to a configurable
> scan handler, we should make sure no platform devices would be
> created for them even if the scan handler is compiled out.
> 
> Fix this problem for lpss devices by introducing a dummy
> lpss scan handler in this patch.
> 
> Plus, if lpt_clk_init() fails, we need this dummy scan handler as well.
> 
> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
> ---
>  drivers/acpi/Makefile    |  2 +-
>  drivers/acpi/acpi_lpss.c | 69 ++++++++++++++++++++++++++++++++++--------------
>  drivers/acpi/internal.h  |  4 ---
>  3 files changed, 50 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
> index 171efc2..605eff7 100644
> --- a/drivers/acpi/Makefile
> +++ b/drivers/acpi/Makefile
> @@ -39,7 +39,7 @@ acpi-y				+= processor_core.o
>  acpi-y				+= ec.o
>  acpi-$(CONFIG_ACPI_DOCK)	+= dock.o
>  acpi-y				+= pci_root.o pci_link.o pci_irq.o
> -acpi-$(CONFIG_X86_INTEL_LPSS)	+= acpi_lpss.o
> +acpi-y				+= acpi_lpss.o
>  acpi-y				+= acpi_platform.o
>  acpi-y				+= acpi_pnp.o
>  acpi-y				+= power.o
> diff --git a/drivers/acpi/acpi_lpss.c b/drivers/acpi/acpi_lpss.c
> index 69e29f4..965428f 100644
> --- a/drivers/acpi/acpi_lpss.c
> +++ b/drivers/acpi/acpi_lpss.c
> @@ -24,6 +24,8 @@
>  
>  ACPI_MODULE_NAME("acpi_lpss");
>  
> +#ifdef CONFIG_X86_INTEL_LPSS
> +
>  #define LPSS_CLK_SIZE	0x04
>  #define LPSS_LTR_SIZE	0x18
>  
> @@ -159,40 +161,50 @@ static struct lpss_device_desc byt_i2c_dev_desc = {
>  	.shared_clock = &i2c_clock,
>  };
>  
> +#define LPSS_PTR(desc) ((unsigned long)&desc)
> +
> +#else
> +
> +#define LPSS_PTR(desc) 0
> +
> +#endif
> +
>  static const struct acpi_device_id acpi_lpss_device_ids[] = {
>  	/* Generic LPSS devices */
> -	{ "INTL9C60", (unsigned long)&lpss_dma_desc },
> +	{ "INTL9C60", LPSS_PTR(lpss_dma_desc) },
>  
>  	/* Lynxpoint LPSS devices */
> -	{ "INT33C0", (unsigned long)&lpt_dev_desc },
> -	{ "INT33C1", (unsigned long)&lpt_dev_desc },
> -	{ "INT33C2", (unsigned long)&lpt_dev_desc },
> -	{ "INT33C3", (unsigned long)&lpt_dev_desc },
> -	{ "INT33C4", (unsigned long)&lpt_uart_dev_desc },
> -	{ "INT33C5", (unsigned long)&lpt_uart_dev_desc },
> -	{ "INT33C6", (unsigned long)&lpt_sdio_dev_desc },
> +	{ "INT33C0", LPSS_PTR(lpt_dev_desc) },
> +	{ "INT33C1", LPSS_PTR(lpt_dev_desc) },
> +	{ "INT33C2", LPSS_PTR(lpt_dev_desc) },
> +	{ "INT33C3", LPSS_PTR(lpt_dev_desc) },
> +	{ "INT33C4", LPSS_PTR(lpt_uart_dev_desc) },
> +	{ "INT33C5", LPSS_PTR(lpt_uart_dev_desc) },
> +	{ "INT33C6", LPSS_PTR(lpt_sdio_dev_desc) },
>  	{ "INT33C7", },
>  
>  	/* BayTrail LPSS devices */
> -	{ "80860F09", (unsigned long)&byt_pwm_dev_desc },
> -	{ "80860F0A", (unsigned long)&byt_uart_dev_desc },
> -	{ "80860F0E", (unsigned long)&byt_spi_dev_desc },
> -	{ "80860F14", (unsigned long)&byt_sdio_dev_desc },
> -	{ "80860F41", (unsigned long)&byt_i2c_dev_desc },
> +	{ "80860F09", LPSS_PTR(byt_pwm_dev_desc) },
> +	{ "80860F0A", LPSS_PTR(byt_uart_dev_desc) },
> +	{ "80860F0E", LPSS_PTR(byt_spi_dev_desc) },
> +	{ "80860F14", LPSS_PTR(byt_sdio_dev_desc) },
> +	{ "80860F41", LPSS_PTR(byt_i2c_dev_desc) },
>  	{ "INT33B2", },
>  
> -	{ "INT3430", (unsigned long)&lpt_dev_desc },
> -	{ "INT3431", (unsigned long)&lpt_dev_desc },
> -	{ "INT3432", (unsigned long)&lpt_dev_desc },
> -	{ "INT3433", (unsigned long)&lpt_dev_desc },
> -	{ "INT3434", (unsigned long)&lpt_uart_dev_desc },
> -	{ "INT3435", (unsigned long)&lpt_uart_dev_desc },
> -	{ "INT3436", (unsigned long)&lpt_sdio_dev_desc },
> +	{ "INT3430", LPSS_PTR(lpt_dev_desc) },
> +	{ "INT3431", LPSS_PTR(lpt_dev_desc) },
> +	{ "INT3432", LPSS_PTR(lpt_dev_desc) },
> +	{ "INT3433", LPSS_PTR(lpt_dev_desc) },
> +	{ "INT3434", LPSS_PTR(lpt_uart_dev_desc) },
> +	{ "INT3435", LPSS_PTR(lpt_uart_dev_desc) },
> +	{ "INT3436", LPSS_PTR(lpt_sdio_dev_desc) },
>  	{ "INT3437", },
>  
>  	{ }
>  };
>  
> +#ifdef CONFIG_X86_INTEL_LPSS
> +
>  static int is_memory(struct acpi_resource *res, void *not_used)
>  {
>  	struct resource r;
> @@ -511,10 +523,27 @@ static struct acpi_scan_handler lpss_handler = {
>  	.unbind = acpi_lpss_unbind,
>  };
>  
> +#endif /* CONFIG_X86_INTEL_LPSS */
> +
> +static int acpi_lpss_dummy_attach(struct acpi_device *adev,
> +				const struct acpi_device_id *id)
> +{
> +	return 1;
> +}
> +
> +static struct acpi_scan_handler lpss_dummy_handler = {
> +	.ids = acpi_lpss_device_ids,
> +	.attach = acpi_lpss_dummy_attach,
> +};
> +
>  void __init acpi_lpss_init(void)
>  {
> +#ifdef CONFIG_X86_INTEL_LPSS
>  	if (!lpt_clk_init()) {
>  		bus_register_notifier(&platform_bus_type, &acpi_lpss_nb);
>  		acpi_scan_add_handler(&lpss_handler);
> +		return;
>  	}
> +#endif

This whole #ifndef dance is ugly as hell. Can't we do any better?

> +	acpi_scan_add_handler(&lpss_dummy_handler);

Also I don't like these "dummy" things at all. Can't we make the code
work so that those are not needed?

>  }
> diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
> index 4a9e999..bc7d102 100644
> --- a/drivers/acpi/internal.h
> +++ b/drivers/acpi/internal.h
> @@ -65,11 +65,7 @@ int acpi_debugfs_init(void);
>  #else
>  static inline void acpi_debugfs_init(void) { return; }
>  #endif
> -#ifdef CONFIG_X86_INTEL_LPSS
>  void acpi_lpss_init(void);
> -#else
> -static inline void acpi_lpss_init(void) {}
> -#endif
>  
>  acpi_status acpi_hotplug_schedule(struct acpi_device *adev, u32 src);
>  bool acpi_queue_hotplug_work(struct work_struct *work);
> -- 
> 1.8.3.2
> 
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