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authorLokesh Vutla <lokeshvutla@ti.com>2016-10-27 11:27:25 +0530
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-11-26 09:54:53 +0100
commit1f995573bac8a84ff91e568d8a1889bddd482a13 (patch)
treec7e85139f1cf2622f82a48c4f443eb9e7bc28d5a
parentc8aa3e98c1a8bc46c0f63cc444bcf2d05dd64759 (diff)
downloadlinux-linaro-stable-1f995573bac8a84ff91e568d8a1889bddd482a13.tar.gz
rtc: omap: Fix selecting external osc
commit 3984903a2e3906d3def220e688040ce93368200a upstream. RTC can be clocked from an external 32KHz oscillator, or from the Peripheral PLL. The RTC has an internal oscillator buffer to support direct operation with a crystal. ---------------------------------------- | Device --------- | | | | | | | RTCSS | | | --------- | | | OSC |<------| RTC | | | | |------>| OSC |--- | | | | -------- | | | | | ----|clk | | | -------- | | | | | | PRCM |--- | | | | -------- -------- | ---------------------------------------- The RTC functional clock is sourced by default from the clock derived from the Peripheral PLL. In order to select source as external osc clk the following changes needs to be done: - Enable the RTC OSC (RTC_OSC_REG[4]OSC32K_GZ = 0) - Enable the clock mux(RTC_OSC_REG[6]K32CLK_EN = 1) - Select the external clock source (RTC_OSC_REG[3]32KCLK_SEL = 1) Fixes: 399cf0f63f6f2 ("rtc: omap: Add external clock enabling support") Signed-off-by: Keerthy <j-keerthy@ti.com> Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com> Signed-off-by: Dave Gerlach <d-gerlach@ti.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/rtc/rtc-omap.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c
index ec2e9c5fb993..22394fe30579 100644
--- a/drivers/rtc/rtc-omap.c
+++ b/drivers/rtc/rtc-omap.c
@@ -109,6 +109,7 @@
/* OMAP_RTC_OSC_REG bit fields: */
#define OMAP_RTC_OSC_32KCLK_EN BIT(6)
#define OMAP_RTC_OSC_SEL_32KCLK_SRC BIT(3)
+#define OMAP_RTC_OSC_OSC32K_GZ_DISABLE BIT(4)
/* OMAP_RTC_IRQWAKEEN bit fields: */
#define OMAP_RTC_IRQWAKEEN_ALARM_WAKEEN BIT(1)
@@ -646,8 +647,9 @@ static int omap_rtc_probe(struct platform_device *pdev)
*/
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);
+ reg &= ~OMAP_RTC_OSC_OSC32K_GZ_DISABLE;
+ reg |= OMAP_RTC_OSC_32KCLK_EN | OMAP_RTC_OSC_SEL_32KCLK_SRC;
+ rtc_writel(rtc, OMAP_RTC_OSC_REG, reg);
}
rtc->type->lock(rtc);