[PATCH 4/5] rtc: at91sam9: get sclk rate after enabling it

From: Alexandre Belloni
Date: Wed Jul 29 2015 - 20:25:05 EST


See help for clk_get_rate(): "obtain the current clock rate (in Hz) for a
clock source. This is only valid once the clock source has been enabled."

It currently returns the correct value but that may not stay that way.

Signed-off-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx>
---
drivers/rtc/rtc-at91sam9.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/rtc/rtc-at91sam9.c b/drivers/rtc/rtc-at91sam9.c
index 23f721d049b2..f9e85ace5e71 100644
--- a/drivers/rtc/rtc-at91sam9.c
+++ b/drivers/rtc/rtc-at91sam9.c
@@ -425,18 +425,19 @@ static int at91_rtc_probe(struct platform_device *pdev)
if (IS_ERR(rtc->sclk))
return PTR_ERR(rtc->sclk);

- sclk_rate = clk_get_rate(rtc->sclk);
- if (!sclk_rate || sclk_rate > AT91_RTT_RTPRES) {
- dev_err(&pdev->dev, "Invalid slow clock rate\n");
- return -EINVAL;
- }
-
ret = clk_prepare_enable(rtc->sclk);
if (ret) {
dev_err(&pdev->dev, "Could not enable slow clock\n");
return ret;
}

+ sclk_rate = clk_get_rate(rtc->sclk);
+ if (!sclk_rate || sclk_rate > AT91_RTT_RTPRES) {
+ dev_err(&pdev->dev, "Invalid slow clock rate\n");
+ ret = -EINVAL;
+ goto err_clk;
+ }
+
mr = rtt_readl(rtc, MR);

/* unless RTT is counting at 1 Hz, re-initialize it */
--
2.1.4

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