[PATCH v7 08/10] rtc: at91sam9: use clk API instead of relying on AT91_SLOW_CLOCK
From: Boris BREZILLON <hidden>
Date: 2014-09-23 09:40:28
Also in:
linux-devicetree, linux-rtc, lkml
Subsystem:
real time clock (rtc) subsystem, the rest · Maintainers:
Alexandre Belloni, Linus Torvalds
The RTT block is using the slow clock which is accessible through the clk API. Use the clk API to retrieve, enable and get the slow clk rate instead of the AT91_SLOW_CLOCK macro (which hardcodes the slow clk rate). Doing this allows us to reference the clk thus preventing the CCF from disabling it during the "disable unused" phase. Signed-off-by: Boris BREZILLON <redacted> Acked-by: Alexandre Belloni <redacted> Acked-by: Nicolas Ferre <redacted> --- drivers/rtc/rtc-at91sam9.c | 28 ++++++++++++++++++++++++---- 1 file changed, 24 insertions(+), 4 deletions(-)
diff --git a/drivers/rtc/rtc-at91sam9.c b/drivers/rtc/rtc-at91sam9.c
index be9c28b..d3bbe29 100644
--- a/drivers/rtc/rtc-at91sam9.c
+++ b/drivers/rtc/rtc-at91sam9.c@@ -23,6 +23,7 @@ #include <linux/io.h> #include <linux/mfd/syscon.h> #include <linux/regmap.h> +#include <linux/clk.h> /* * This driver uses two configurable hardware resources that live in the
@@ -61,8 +62,6 @@ #define AT91_RTT_ALMS (1 << 0) /* Real-time Alarm Status */ #define AT91_RTT_RTTINC (1 << 1) /* Real-time Timer Increment */ -#define AT91_SLOW_CLOCK 32768 - /* * We store ALARM_DISABLED in ALMV to record that no alarm is set. * It's also the reset value for that field.
@@ -77,6 +76,7 @@ struct sam9_rtc { struct regmap *gpbr; unsigned int gpbr_offset; int irq; + struct clk *sclk; }; #define rtt_readl(rtc, field) \
@@ -328,6 +328,7 @@ static int at91_rtc_probe(struct platform_device *pdev) struct sam9_rtc *rtc; int ret, irq; u32 mr; + unsigned int sclk_rate; irq = platform_get_irq(pdev, 0); if (irq < 0) {
@@ -385,11 +386,27 @@ static int at91_rtc_probe(struct platform_device *pdev) return -ENOMEM; } + rtc->sclk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(rtc->sclk)) + return PTR_ERR(rtc->sclk); + + sclk_rate = clk_get_rate(rtc->sclk); + if (!sclk_rate || sclk_rate > AT91_RTT_RTTRST) { + dev_err(&pdev->dev, "Invalid slow clock rate"); + return -EINVAL; + } + + ret = clk_prepare_enable(rtc->sclk); + if (ret) { + dev_err(&pdev->dev, "Could not enable slow clock"); + return ret; + } + mr = rtt_readl(rtc, MR); /* unless RTT is counting at 1 Hz, re-initialize it */ - if ((mr & AT91_RTT_RTPRES) != AT91_SLOW_CLOCK) { - mr = AT91_RTT_RTTRST | (AT91_SLOW_CLOCK & AT91_RTT_RTPRES); + if ((mr & AT91_RTT_RTPRES) != sclk_rate) { + mr = AT91_RTT_RTTRST | (sclk_rate & AT91_RTT_RTPRES); gpbr_writel(rtc, 0); }
@@ -434,6 +451,9 @@ static int at91_rtc_remove(struct platform_device *pdev) /* disable all interrupts */ rtt_writel(rtc, MR, mr & ~(AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN)); + if (!IS_ERR(rtc->sclk)) + clk_disable_unprepare(rtc->sclk); + return 0; }
--
1.9.1