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From:   Nicolas Ferre <nicolas.ferre@microchip.com>
To:     <linux-kernel@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <stern@rowland.harvard.edu>, <gregkh@linuxfoundation.org>
CC:     Alexandre Belloni <alexandre.belloni@bootlin.com>,
        Ludovic Desroches <ludovic.desroches@microchip.com>,
        <Boris.Krasnovskiy@lairdconnect.com>, <linux-usb@vger.kernel.org>,
        Nicolas Ferre <nicolas.ferre@microchip.com>
Subject: [PATCH 2/3] USB: host: ohci-at91: suspend: delay needed before to stop clocks
Date:   Wed, 11 Sep 2019 08:41:53 +0200
Message-ID: <20190911064154.28633-3-nicolas.ferre@microchip.com>
In-Reply-To: <20190911064154.28633-1-nicolas.ferre@microchip.com>
References: <20190911064154.28633-1-nicolas.ferre@microchip.com>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

In order to completely remove marginal power consumption in PM suspend,
we need to let the controller settle down before being stopped.
In ohci_hcd_at91_drv_suspend() function, one additional delay is needed before
to stop the clocks.

Reported-by: Boris Krasnovskiy <Boris.Krasnovskiy@lairdconnect.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
---
 drivers/usb/host/ohci-at91.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/usb/host/ohci-at91.c b/drivers/usb/host/ohci-at91.c
index cb63bcd5049a..85d67fe42d59 100644
--- a/drivers/usb/host/ohci-at91.c
+++ b/drivers/usb/host/ohci-at91.c
@@ -628,6 +628,7 @@ ohci_hcd_at91_drv_suspend(struct device *dev)
 
 		/* flush the writes */
 		(void) ohci_readl (ohci, &ohci->regs->control);
+		msleep(1);
 		at91_stop_clock(ohci_at91);
 	}
 
-- 
2.17.1