[rtc-linux] [PATCH v3 3/3] rtc: omap: Add external clock enabling support
From: Keerthy <j-keerthy@ti.com>
Date: 2015-08-18 06:18:59
Subsystem:
real time clock (rtc) subsystem, the rest · Maintainers:
Alexandre Belloni, Linus Torvalds
Configure the clock source to external clock if available. External clock is preferred as it can be ticking during suspend. Signed-off-by: Keerthy <j-keerthy@ti.com> --- drivers/rtc/rtc-omap.c | 33 ++++++++++++++++++++++++++++++--- 1 file changed, 30 insertions(+), 3 deletions(-)
diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c
index f31c012..255f7b7 100644
--- a/drivers/rtc/rtc-omap.c
+++ b/drivers/rtc/rtc-omap.c@@ -108,6 +108,7 @@ /* OMAP_RTC_OSC_REG bit fields: */ #define OMAP_RTC_OSC_32KCLK_EN BIT(6) +#define OMAP_RTC_OSC_SEL_32KCLK_SRC BIT(3) /* OMAP_RTC_IRQWAKEEN bit fields: */ #define OMAP_RTC_IRQWAKEEN_ALARM_WAKEEN BIT(1)
@@ -138,6 +139,7 @@ struct omap_rtc { int irq_timer; u8 interrupts_reg; bool is_pmic_controller; + bool has_ext_clk; const struct omap_rtc_device_type *type; };
@@ -555,11 +557,19 @@ static int omap_rtc_probe(struct platform_device *pdev) if (rtc->irq_alarm <= 0) return -ENOENT; - rtc->clk = devm_clk_get(&pdev->dev, "int-clk"); - - if (!IS_ERR(rtc->clk)) + rtc->clk = devm_clk_get(&pdev->dev, "ext-clk"); + if (!IS_ERR(rtc->clk)) { + rtc->has_ext_clk = true; clk_prepare_enable(rtc->clk); + } else { + rtc->clk = devm_clk_get(&pdev->dev, "int-clk"); + if (IS_ERR(rtc->clk)) + goto no_clk; + } + clk_prepare_enable(rtc->clk); + +no_clk: res = platform_get_resource(pdev, IORESOURCE_MEM, 0); rtc->base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(rtc->base))
@@ -634,6 +644,16 @@ static int omap_rtc_probe(struct platform_device *pdev) if (reg != new_ctrl) rtc_write(rtc, OMAP_RTC_CTRL_REG, new_ctrl); + /* + * If we have the external clock then switch to it so we can keep + * ticking across suspend. + */ + if (rtc->has_ext_clk) { + reg = rtc_read(rtc, OMAP_RTC_OSC_REG); + rtc_write(rtc, OMAP_RTC_OSC_REG, + reg | OMAP_RTC_OSC_SEL_32KCLK_SRC); + } + rtc->type->lock(rtc); device_init_wakeup(&pdev->dev, true);
@@ -679,6 +699,7 @@ err: static int __exit omap_rtc_remove(struct platform_device *pdev) { struct omap_rtc *rtc = platform_get_drvdata(pdev); + u8 reg; if (pm_power_off == omap_rtc_power_off && omap_rtc_power_off_rtc == rtc) {
@@ -695,6 +716,12 @@ static int __exit omap_rtc_remove(struct platform_device *pdev) /* leave rtc running, but disable irqs */ rtc_write(rtc, OMAP_RTC_INTERRUPTS_REG, 0); + if (rtc->has_ext_clk) { + reg = rtc_read(rtc, OMAP_RTC_OSC_REG); + reg &= ~OMAP_RTC_OSC_SEL_32KCLK_SRC; + rtc_write(rtc, OMAP_RTC_OSC_REG, reg); + } + rtc->type->lock(rtc); /* Disable the clock/module */
--
1.9.1
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