linux-kernel - [PATCH 7/8] ARM: at91: pm: disable RC oscillator in ULP0

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Message-ID: <1550159642-26878-8-git-send-email-claudiu.beznea@microchip.com>
Date:   Thu, 14 Feb 2019 15:55:01 +0000
From:   <Claudiu.Beznea@...rochip.com>
To:     <robh+dt@...nel.org>, <mark.rutland@....com>,
        <Nicolas.Ferre@...rochip.com>, <alexandre.belloni@...tlin.com>,
        <Ludovic.Desroches@...rochip.com>, <linux@...linux.org.uk>,
        <mturquette@...libre.com>, <sboyd@...nel.org>
CC:     <devicetree@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <linux-clk@...r.kernel.org>,
        <Claudiu.Beznea@...rochip.com>
Subject: [PATCH 7/8] ARM: at91: pm: disable RC oscillator in ULP0

From: Claudiu Beznea <claudiu.beznea@...rochip.com>

Disable RC oscillator in ULP0 as datasheet specifies.

Signed-off-by: Claudiu Beznea <claudiu.beznea@...rochip.com>
---
 arch/arm/mach-at91/pm_suspend.S | 39 +++++++++++++++++++++++++++++++++++++--
 1 file changed, 37 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mach-at91/pm_suspend.S b/arch/arm/mach-at91/pm_suspend.S
index 8b18cad1dcf5..5c33023f9129 100644
--- a/arch/arm/mach-at91/pm_suspend.S
+++ b/arch/arm/mach-at91/pm_suspend.S
@@ -178,11 +178,46 @@ ENDPROC(at91_backup_mode)
 	orr	tmp1, tmp1, #AT91_PMC_KEY
 	str	tmp1, [pmc, #AT91_CKGR_MOR]
 
+	/* Save RC oscillator state */
+	ldr	tmp1, [pmc, #AT91_PMC_SR]
+	str	tmp1, .saved_osc_status
+	tst	tmp1, #AT91_PMC_MOSCRCS
+	bne	1f
+
+	/* Turn off RC oscillator */
+	ldr	tmp1, [pmc, #AT91_CKGR_MOR]
+	bic	tmp1, tmp1, #AT91_PMC_MOSCRCEN
+	bic	tmp1, tmp1, #AT91_PMC_KEY_MASK
+	orr	tmp1, tmp1, #AT91_PMC_KEY
+	str	tmp1, [pmc, #AT91_CKGR_MOR]
+
+	/* Wait main RC disabled done */
+2:	ldr	tmp1, [pmc, #AT91_PMC_SR]
+	tst	tmp1, #AT91_PMC_MOSCRCS
+	bne	2b
+
 	/* Wait for interrupt */
-	at91_cpu_idle
+1:	at91_cpu_idle
 
-	/* Turn on the crystal oscillator */
+	/* Restore RC oscillator state */
+	ldr	tmp1, .saved_osc_status
+	tst	tmp1, #AT91_PMC_MOSCRCS
+	beq	4f
+
+	/* Turn on RC oscillator */
 	ldr	tmp1, [pmc, #AT91_CKGR_MOR]
+	orr	tmp1, tmp1, #AT91_PMC_MOSCRCEN
+	bic	tmp1, tmp1, #AT91_PMC_KEY_MASK
+	orr	tmp1, tmp1, #AT91_PMC_KEY
+	str	tmp1, [pmc, #AT91_CKGR_MOR]
+
+	/* Wait main RC stabilization */
+3:	ldr	tmp1, [pmc, #AT91_PMC_SR]
+	tst	tmp1, #AT91_PMC_MOSCRCS
+	beq	3b
+
+	/* Turn on the crystal oscillator */
+4:	ldr	tmp1, [pmc, #AT91_CKGR_MOR]
 	orr	tmp1, tmp1, #AT91_PMC_MOSCEN
 	orr	tmp1, tmp1, #AT91_PMC_KEY
 	str	tmp1, [pmc, #AT91_CKGR_MOR]
-- 
2.7.4