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rtc: at91rm9200: get and use slow clock 

Commit dca1a4b5ff ("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 at91rm9200 rtc.

Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
This commit is contained in:
Alexandre Belloni 2015-07-31 11:39:51 +02:00
parent 202cc98acf
commit 11f67a8bbf
1 changed files with 24 additions and 3 deletions
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27
drivers/rtc/rtc-at91rm9200.c
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@ -19,6 +19,7 @@
*/ */
#include <linux/bcd.h> #include <linux/bcd.h>
#include <linux/clk.h>
#include <linux/completion.h> #include <linux/completion.h>
#include <linux/interrupt.h> #include <linux/interrupt.h>
#include <linux/ioctl.h> #include <linux/ioctl.h>
@ -59,6 +60,7 @@ static bool suspended;
static DEFINE_SPINLOCK(suspended_lock); static DEFINE_SPINLOCK(suspended_lock);
static unsigned long cached_events; static unsigned long cached_events;
static u32 at91_rtc_imr; static u32 at91_rtc_imr;
static struct clk *sclk;
static void at91_rtc_write_ier(u32 mask) static void at91_rtc_write_ier(u32 mask)
{ {
@ -407,6 +409,16 @@ static int __init at91_rtc_probe(struct platform_device *pdev)
return -ENOMEM; return -ENOMEM;
} }
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;
}
at91_rtc_write(AT91_RTC_CR, 0); at91_rtc_write(AT91_RTC_CR, 0);
at91_rtc_write(AT91_RTC_MR, 0); /* 24 hour mode */ at91_rtc_write(AT91_RTC_MR, 0); /* 24 hour mode */
@ -420,7 +432,7 @@ static int __init at91_rtc_probe(struct platform_device *pdev)
"at91_rtc", pdev); "at91_rtc", pdev);
if (ret) { if (ret) {
dev_err(&pdev->dev, "IRQ %d already in use.\n", irq); dev_err(&pdev->dev, "IRQ %d already in use.\n", irq);
return ret; goto err_clk;
} }
/* cpu init code should really have flagged this device as /* cpu init code should really have flagged this device as
@ -431,8 +443,10 @@ static int __init at91_rtc_probe(struct platform_device *pdev)
rtc = devm_rtc_device_register(&pdev->dev, pdev->name, rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
&at91_rtc_ops, THIS_MODULE); &at91_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc)) if (IS_ERR(rtc)) {
return PTR_ERR(rtc); ret = PTR_ERR(rtc);
goto err_clk;
}
platform_set_drvdata(pdev, rtc); platform_set_drvdata(pdev, rtc);
/* enable SECEV interrupt in order to initialize at91_rtc_upd_rdy /* enable SECEV interrupt in order to initialize at91_rtc_upd_rdy
@ -442,6 +456,11 @@ static int __init at91_rtc_probe(struct platform_device *pdev)
dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n"); dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n");
return 0; return 0;
err_clk:
clk_disable_unprepare(sclk);
return ret;
} }
/* /*
@ -454,6 +473,8 @@ static int __exit at91_rtc_remove(struct platform_device *pdev)
AT91_RTC_SECEV | AT91_RTC_TIMEV | AT91_RTC_SECEV | AT91_RTC_TIMEV |
AT91_RTC_CALEV); AT91_RTC_CALEV);
clk_disable_unprepare(sclk);
return 0; return 0;
} }