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

[Zhang Rui]

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@xxxxxxxxx>
---
 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
+	acpi_scan_add_handler(&lpss_dummy_handler);
 }
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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