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Date: Thu, 22 Mar 2007 11:08:21 -0700
From: David Brownell <david-b@...bell.net>
To: linux-pm@...ts.linux-foundation.org,
Linux Kernel list <linux-kernel@...r.kernel.org>
Cc: Andrew Victor <andrew@...people.com>
Subject: [patch 2/2] clk_must_disable() implementation on AT91
This supports the new clk_must_disable() interface for AT91 systems:
- Implement the call, replacing at91_suspend_entering_slow_clock()
and eliminating various "that's not exported" build warnings;
- Use it in three drivers: USB Host, USB Peripheral, and RS232 serial.
Briefly, those are three of the drivers that need to act differently when
going into deeper sleep states (suspend-to-RAM, vs standby), since among
other things they can't act as wakeup event sources without using the
clocks which are disabled in those deeper sleep states.
(The at91_ethernet driver would be another such driver, but it doesn't
currently implement wake-on-LAN even in the "standby" mode.)
Signed-off-by: David Brownell <dbrownell@...rs.sourceforge.net>
---
arch/arm/mach-at91/clock.c | 18 ++++++++++++++++++
arch/arm/mach-at91/generic.h | 1 +
arch/arm/mach-at91/pm.c | 7 +------
drivers/serial/atmel_serial.c | 3 ++-
drivers/usb/gadget/at91_udc.c | 2 +-
drivers/usb/host/ohci-at91.c | 2 +-
6 files changed, 24 insertions(+), 9 deletions(-)
Index: at91/arch/arm/mach-at91/clock.c
===================================================================
--- at91.orig/arch/arm/mach-at91/clock.c 2007-02-19 16:15:13.000000000 -0800
+++ at91/arch/arm/mach-at91/clock.c 2007-02-19 17:45:25.000000000 -0800
@@ -33,6 +33,7 @@
#include <asm/arch/cpu.h>
#include "clock.h"
+#include "generic.h"
/*
@@ -255,6 +256,23 @@ EXPORT_SYMBOL(clk_get_rate);
/*------------------------------------------------------------------------*/
+#ifdef CONFIG_PM
+
+int clk_must_disable(struct clk *clk)
+{
+ if (!at91_suspend_entering_slow_clock())
+ return 0;
+
+ while (clk->parent)
+ clk = clk->parent;
+ return clk != &clk32k;
+}
+EXPORT_SYMBOL(clk_must_disable);
+
+#endif
+
+/*------------------------------------------------------------------------*/
+
#ifdef CONFIG_AT91_PROGRAMMABLE_CLOCKS
/*
Index: at91/arch/arm/mach-at91/generic.h
===================================================================
--- at91.orig/arch/arm/mach-at91/generic.h 2007-02-19 17:30:37.000000000 -0800
+++ at91/arch/arm/mach-at91/generic.h 2007-02-19 17:45:25.000000000 -0800
@@ -38,6 +38,7 @@ extern void __init at91_clock_associate(
/* Power Management */
extern void at91_irq_suspend(void);
extern void at91_irq_resume(void);
+extern int at91_suspend_entering_slow_clock(void);
/* GPIO */
#define AT91RM9200_PQFP 3 /* AT91RM9200 PQFP package has 3 banks */
Index: at91/arch/arm/mach-at91/pm.c
===================================================================
--- at91.orig/arch/arm/mach-at91/pm.c 2007-02-19 13:57:53.000000000 -0800
+++ at91/arch/arm/mach-at91/pm.c 2007-02-19 17:45:25.000000000 -0800
@@ -104,20 +104,15 @@ static int at91_pm_verify_clocks(void)
}
/*
- * Call this from platform driver suspend() to see how deeply to suspend.
+ * This is called from clk_must_disable(), to see how deeply to suspend.
* For example, some controllers (like OHCI) need one of the PLL clocks
* in order to act as a wakeup source, and those are not available when
* going into slow clock mode.
- *
- * REVISIT: generalize as clk_will_be_available(clk)? Other platforms have
- * the very same problem (but not using at91 main_clk), and it'd be better
- * to add one generic API rather than lots of platform-specific ones.
*/
int at91_suspend_entering_slow_clock(void)
{
return (target_state == PM_SUSPEND_MEM);
}
-EXPORT_SYMBOL(at91_suspend_entering_slow_clock);
static void (*slow_clock)(void);
Index: at91/drivers/serial/atmel_serial.c
===================================================================
--- at91.orig/drivers/serial/atmel_serial.c 2007-02-19 13:57:53.000000000 -0800
+++ at91/drivers/serial/atmel_serial.c 2007-02-19 17:45:25.000000000 -0800
@@ -888,7 +888,8 @@ static int atmel_serial_suspend(struct p
struct uart_port *port = platform_get_drvdata(pdev);
struct atmel_uart_port *atmel_port = (struct atmel_uart_port *) port;
- if (device_may_wakeup(&pdev->dev) && !at91_suspend_entering_slow_clock())
+ if (device_may_wakeup(&pdev->dev)
+ && !clk_must_disable(atmel_port->clk))
enable_irq_wake(port->irq);
else {
uart_suspend_port(&atmel_uart, port);
Index: at91/drivers/usb/gadget/at91_udc.c
===================================================================
--- at91.orig/drivers/usb/gadget/at91_udc.c 2007-02-19 13:57:53.000000000 -0800
+++ at91/drivers/usb/gadget/at91_udc.c 2007-02-19 17:45:25.000000000 -0800
@@ -1804,7 +1804,7 @@ static int at91udc_suspend(struct platfo
*/
if ((!udc->suspended && udc->addr)
|| !wake
- || at91_suspend_entering_slow_clock()) {
+ || clk_must_disable(udc->fclk)) {
pullup(udc, 0);
wake = 0;
} else
Index: at91/drivers/usb/host/ohci-at91.c
===================================================================
--- at91.orig/drivers/usb/host/ohci-at91.c 2007-02-19 13:57:53.000000000 -0800
+++ at91/drivers/usb/host/ohci-at91.c 2007-02-19 17:45:25.000000000 -0800
@@ -299,7 +299,7 @@ ohci_hcd_at91_drv_suspend(struct platfor
*
* REVISIT: some boards will be able to turn VBUS off...
*/
- if (at91_suspend_entering_slow_clock()) {
+ if (clk_must_disable(fclk)) {
ohci_usb_reset (ohci);
at91_stop_clock();
}
-
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