Commit-ID: 1f174a1a2cdebc65138e6ed1448b842e73200bb5
Gitweb: https://git.kernel.org/tip/1f174a1a2cdebc65138e6ed1448b842e73200bb5
Author: Dinh Nguyen <dinguyen@xxxxxxxxxx>
AuthorDate: Mon, 17 Sep 2018 09:52:14 -0500
Committer: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
CommitDate: Sun, 7 Oct 2018 14:16:35 +0200
clocksource/drivers/dw_apb: Add reset control
Add code to retrieve the reset property from the dw-apb timers and if
the property is available, the safe operation is to assert the timer
into reset, and followed by a deassert of the timer reset (brings the
timer out of reset).
This patch is needed for systems where the bootloader has left the timer
not used in reset.
- Trivial conflict with commit a74bd1ad7a:
"Convert to using %pOFn instead of device_node.name"
Reported-by: Marek Vasut <marex@xxxxxxx>
Signed-off-by: Dinh Nguyen <dinguyen@xxxxxxxxxx>
Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
---
drivers/clocksource/dw_apb_timer_of.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/clocksource/dw_apb_timer_of.c b/drivers/clocksource/dw_apb_timer_of.c
index fabaa29cc3a4..db410acd8964 100644
--- a/drivers/clocksource/dw_apb_timer_of.c
+++ b/drivers/clocksource/dw_apb_timer_of.c
@@ -22,6 +22,7 @@
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/clk.h>
+#include <linux/reset.h>
#include <linux/sched_clock.h>
static void __init timer_get_base_and_rate(struct device_node *np,
@@ -29,12 +30,23 @@ static void __init timer_get_base_and_rate(struct device_node *np,
{
struct clk *timer_clk;
struct clk *pclk;
+ struct reset_control *rstc;
*base = of_iomap(np, 0);
if (!*base)
panic("Unable to map regs for %pOFn", np);
+ /*
+ * Reset the timer if the reset control is available, wiping
+ * out the state the firmware may have left it
+ */
+ rstc = of_reset_control_get(np, NULL);
+ if (!IS_ERR(rstc)) {
+ reset_control_assert(rstc);
+ reset_control_deassert(rstc);
+ }
+
/*
* Not all implementations use a periphal clock, so don't panic
* if it's not present
|