[PATCH v3 3/5] power/reset: at91-reset: get and use slow clock

From: Alexandre Belloni
Date: Tue Aug 11 2015 - 05:14:05 EST


Commit dca1a4b5ff6e ("clk: at91: keep slow clk enabled to prevent system
hang") added a workaround for the slow clock as it is not properly handled
by its users.

Get and use the slow clock as it is necessary for the at91 reset
controller.

Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx>
---
drivers/power/reset/at91-reset.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/power/reset/at91-reset.c b/drivers/power/reset/at91-reset.c
index 120f3dec9574..8f0bcb232149 100644
--- a/drivers/power/reset/at91-reset.c
+++ b/drivers/power/reset/at91-reset.c
@@ -11,6 +11,7 @@
* warranty of any kind, whether express or implied.
*/

+#include <linux/clk.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_address.h>
@@ -46,6 +47,7 @@ enum reset_type {
};

static void __iomem *at91_ramc_base[2], *at91_rstc_base;
+static struct clk *sclk;

/*
* unless the SDRAM is cleanly shutdown before we hit the
@@ -193,9 +195,21 @@ static int __init at91_reset_probe(struct platform_device *pdev)
match = of_match_node(at91_reset_of_match, pdev->dev.of_node);
at91_restart_nb.notifier_call = match->data;

+ sclk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(sclk))
+ return PTR_ERR(sclk);
+
+ ret = clk_prepare_enable(sclk);
+ if (ret) {
+ dev_err(&pdev->dev, "Could not enable slow clock\n");
+ return ret;
+ }
+
ret = register_restart_handler(&at91_restart_nb);
- if (ret)
+ if (ret) {
+ clk_disable_unprepare(sclk);
return ret;
+ }

at91_reset_status(pdev);

@@ -205,6 +219,7 @@ static int __init at91_reset_probe(struct platform_device *pdev)
static int __exit at91_reset_remove(struct platform_device *pdev)
{
unregister_restart_handler(&at91_restart_nb);
+ clk_disable_unprepare(sclk);

return 0;
}
--
2.1.4

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