ACPI / scan: Add special handler for Intel Lynxpoint LPSS devices

Devices on the Intel Lynxpoint Low Power Subsystem (LPSS) have some
common features that aren't shared with any other platform devices,
including the clock and LTR (Latency Tolerance Reporting) registers.
It is better to handle those features in common code than to bother
device drivers with doing that (I/O functionality-wise the LPSS
devices are generally compatible with other devices that don't
have those special registers and may be handled by the same drivers).

The clock registers of the LPSS devices are now taken care of by
the special clk-x86-lpss driver, but the MMIO mappings used for
accessing those registers can also be used for accessing the LTR
registers on those devices (LTR support for the Lynxpoint LPSS is
going to be added by a subsequent patch).  Thus it is convenient
to add a special ACPI scan handler for the Lynxpoint LPSS devices
that will create the MMIO mappings for accessing the clock (and
LTR in the future) registers and will register the LPSS devices'
clocks, so the clk-x86-lpss driver will only need to take care of
the main Lynxpoint LPSS clock.

Introduce a special ACPI scan handler for Intel Lynxpoint LPSS
devices as described above.  This also reduces overhead related to
browsing the ACPI namespace in search of the LPSS devices before the
registration of their clocks, removes some LPSS-specific (and
somewhat ugly) code from acpi_platform.c and shrinks the overall code
size slightly.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Mike Turquette <mturquette@linaro.org>

4 files changed, 2 insertions, 175 deletions

diff --git a/drivers/clk/x86/Makefile b/drivers/clk/x86/Makefile
index f9ba4fab0dd..04781389d0f 100644
--- a/drivers/clk/x86/Makefile
+++ b/drivers/clk/x86/Makefile
@@ -1,2 +1,2 @@
-clk-x86-lpss-objs		:= clk-lpss.o clk-lpt.o
+clk-x86-lpss-objs		:= clk-lpt.o
 obj-$(CONFIG_X86_INTEL_LPSS)	+= clk-x86-lpss.o
diff --git a/drivers/clk/x86/clk-lpss.c b/drivers/clk/x86/clk-lpss.c
deleted file mode 100644
index b5e229f3c3d..00000000000
--- a/drivers/clk/x86/clk-lpss.c
+++ /dev/null
@@ -1,99 +0,0 @@
-/*
- * Intel Low Power Subsystem clocks.
- *
- * Copyright (C) 2013, Intel Corporation
- * Authors: Mika Westerberg <mika.westerberg@linux.intel.com>
- *	    Heikki Krogerus <heikki.krogerus@linux.intel.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-
-#include <linux/acpi.h>
-#include <linux/clk.h>
-#include <linux/clk-provider.h>
-#include <linux/err.h>
-#include <linux/io.h>
-#include <linux/module.h>
-
-static int clk_lpss_is_mmio_resource(struct acpi_resource *res, void *data)
-{
-	struct resource r;
-	return !acpi_dev_resource_memory(res, &r);
-}
-
-static acpi_status clk_lpss_find_mmio(acpi_handle handle, u32 level,
-				      void *data, void **retval)
-{
-	struct resource_list_entry *rentry;
-	struct list_head resource_list;
-	struct acpi_device *adev;
-	const char *uid = data;
-	int ret;
-
-	if (acpi_bus_get_device(handle, &adev))
-		return AE_OK;
-
-	if (uid) {
-		if (!adev->pnp.unique_id)
-			return AE_OK;
-		if (strcmp(uid, adev->pnp.unique_id))
-			return AE_OK;
-	}
-
-	INIT_LIST_HEAD(&resource_list);
-	ret = acpi_dev_get_resources(adev, &resource_list,
-				     clk_lpss_is_mmio_resource, NULL);
-	if (ret < 0)
-		return AE_NO_MEMORY;
-
-	list_for_each_entry(rentry, &resource_list, node)
-		if (resource_type(&rentry->res) == IORESOURCE_MEM) {
-			*(struct resource *)retval = rentry->res;
-			break;
-		}
-
-	acpi_dev_free_resource_list(&resource_list);
-	return AE_OK;
-}
-
-/**
- * clk_register_lpss_gate - register LPSS clock gate
- * @name: name of this clock gate
- * @parent_name: parent clock name
- * @hid: ACPI _HID of the device
- * @uid: ACPI _UID of the device (optional)
- * @offset: LPSS PRV_CLOCK_PARAMS offset
- *
- * Creates and registers LPSS clock gate.
- */
-struct clk *clk_register_lpss_gate(const char *name, const char *parent_name,
-				   const char *hid, const char *uid,
-				   unsigned offset)
-{
-	struct resource res = { };
-	void __iomem *mmio_base;
-	acpi_status status;
-	struct clk *clk;
-
-	/*
-	 * First try to look the device and its mmio resource from the
-	 * ACPI namespace.
-	 */
-	status = acpi_get_devices(hid, clk_lpss_find_mmio, (void *)uid,
-				  (void **)&res);
-	if (ACPI_FAILURE(status) || !res.start)
-		return ERR_PTR(-ENODEV);
-
-	mmio_base = ioremap(res.start, resource_size(&res));
-	if (!mmio_base)
-		return ERR_PTR(-ENOMEM);
-
-	clk = clk_register_gate(NULL, name, parent_name, 0, mmio_base + offset,
-				0, 0, NULL);
-	if (IS_ERR(clk))
-		iounmap(mmio_base);
-
-	return clk;
-}
diff --git a/drivers/clk/x86/clk-lpss.h b/drivers/clk/x86/clk-lpss.h
deleted file mode 100644
index e9460f44229..00000000000
--- a/drivers/clk/x86/clk-lpss.h
+++ /dev/null
@@ -1,36 +0,0 @@
-/*
- * Intel Low Power Subsystem clock.
- *
- * Copyright (C) 2013, Intel Corporation
- * Authors: Mika Westerberg <mika.westerberg@linux.intel.com>
- *	    Heikki Krogerus <heikki.krogerus@linux.intel.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-
-#ifndef __CLK_LPSS_H
-#define __CLK_LPSS_H
-
-#include <linux/err.h>
-#include <linux/errno.h>
-#include <linux/clk.h>
-
-#ifdef CONFIG_ACPI
-extern struct clk *clk_register_lpss_gate(const char *name,
-					  const char *parent_name,
-					  const char *hid, const char *uid,
-					  unsigned offset);
-#else
-static inline struct clk *clk_register_lpss_gate(const char *name,
-						 const char *parent_name,
-						 const char *hid,
-						 const char *uid,
-						 unsigned offset)
-{
-	return ERR_PTR(-ENODEV);
-}
-#endif
-
-#endif /* __CLK_LPSS_H */
diff --git a/drivers/clk/x86/clk-lpt.c b/drivers/clk/x86/clk-lpt.c
index 81298aeef7e..5cf4f468640 100644
--- a/drivers/clk/x86/clk-lpt.c
+++ b/drivers/clk/x86/clk-lpt.c
@@ -10,7 +10,6 @@
  * published by the Free Software Foundation.
  */
 
-#include <linux/acpi.h>
 #include <linux/clk.h>
 #include <linux/clkdev.h>
 #include <linux/clk-provider.h>
@@ -18,8 +17,6 @@
 #include <linux/module.h>
 #include <linux/platform_device.h>
 
-#include "clk-lpss.h"
-
 #define PRV_CLOCK_PARAMS 0x800
 
 static int lpt_clk_probe(struct platform_device *pdev)
@@ -34,40 +31,6 @@ static int lpt_clk_probe(struct platform_device *pdev)
 
 	/* Shared DMA clock */
 	clk_register_clkdev(clk, "hclk", "INTL9C60.0.auto");
-
-	/* SPI clocks */
-	clk = clk_register_lpss_gate("spi0_clk", "lpss_clk", "INT33C0", NULL,
-				     PRV_CLOCK_PARAMS);
-	if (!IS_ERR(clk))
-		clk_register_clkdev(clk, NULL, "INT33C0:00");
-
-	clk = clk_register_lpss_gate("spi1_clk", "lpss_clk", "INT33C1", NULL,
-				     PRV_CLOCK_PARAMS);
-	if (!IS_ERR(clk))
-		clk_register_clkdev(clk, NULL, "INT33C1:00");
-
-	/* I2C clocks */
-	clk = clk_register_lpss_gate("i2c0_clk", "lpss_clk", "INT33C2", NULL,
-				     PRV_CLOCK_PARAMS);
-	if (!IS_ERR(clk))
-		clk_register_clkdev(clk, NULL, "INT33C2:00");
-
-	clk = clk_register_lpss_gate("i2c1_clk", "lpss_clk", "INT33C3", NULL,
-				     PRV_CLOCK_PARAMS);
-	if (!IS_ERR(clk))
-		clk_register_clkdev(clk, NULL, "INT33C3:00");
-
-	/* UART clocks */
-	clk = clk_register_lpss_gate("uart0_clk", "lpss_clk", "INT33C4", NULL,
-				     PRV_CLOCK_PARAMS);
-	if (!IS_ERR(clk))
-		clk_register_clkdev(clk, NULL, "INT33C4:00");
-
-	clk = clk_register_lpss_gate("uart1_clk", "lpss_clk", "INT33C5", NULL,
-				     PRV_CLOCK_PARAMS);
-	if (!IS_ERR(clk))
-		clk_register_clkdev(clk, NULL, "INT33C5:00");
-
 	return 0;
 }
 
@@ -79,8 +42,7 @@ static struct platform_driver lpt_clk_driver = {
 	.probe = lpt_clk_probe,
 };
 
-static int __init lpt_clk_init(void)
+int __init lpt_clk_init(void)
 {
 	return platform_driver_register(&lpt_clk_driver);
 }
-arch_initcall(lpt_clk_init);