linux-kernel - [PATCH/RFT 01/12] ARM: davinci: da8xx: Enable the usb20 "per" clk on phy_clk

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Message-Id: <1475858577-10366-2-git-send-email-ahaslam@baylibre.com>
Date:   Fri,  7 Oct 2016 18:42:46 +0200
From:   ahaslam@...libre.com
To:     gregkh@...uxfoundation.org, robh+dt@...nel.org, nsekhar@...com,
        stern@...land.harvard.edu, khilman@...libre.com,
        sshtylyov@...mvista.com, david@...hnology.com
Cc:     linux-usb@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        Axel Haslam <ahaslam@...libre.com>
Subject: [PATCH/RFT 01/12] ARM: davinci: da8xx: Enable the usb20 "per" clk on phy_clk_enable

From: Axel Haslam <ahaslam@...libre.com>

While probing ochi phy with usb20 phy as a parent clock for usb11_phy,
the usb20_phy clock enable would time out. This is because the usb20
module clock needs to enabled while trying to lock the usb20_phy PLL.

Call clk enable and get for the usb20 peripheral before trying to
enable the phy PLL.

Signed-off-by: Axel Haslam <ahaslam@...libre.com>
---
 arch/arm/mach-davinci/usb-da8xx.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-davinci/usb-da8xx.c b/arch/arm/mach-davinci/usb-da8xx.c
index 9e41a7f..982e105 100644
--- a/arch/arm/mach-davinci/usb-da8xx.c
+++ b/arch/arm/mach-davinci/usb-da8xx.c
@@ -53,11 +53,19 @@ int __init da8xx_register_usb_refclkin(int rate)
 
 static void usb20_phy_clk_enable(struct clk *clk)
 {
+	struct clk *usb20_clk;
 	u32 val;
 	u32 timeout = 500000; /* 500 msec */
 
 	val = readl(DA8XX_SYSCFG0_VIRT(DA8XX_CFGCHIP2_REG));
 
+	usb20_clk = clk_get(NULL, "usb20");
+	if (IS_ERR(usb20_clk)) {
+		pr_err("could not get usb20 clk\n");
+		return;
+	}
+
+	clk_prepare_enable(usb20_clk);
 	/*
 	 * Turn on the USB 2.0 PHY, but just the PLL, and not OTG. The USB 1.1
 	 * host may use the PLL clock without USB 2.0 OTG being used.
@@ -70,11 +78,14 @@ static void usb20_phy_clk_enable(struct clk *clk)
 	while (--timeout) {
 		val = readl(DA8XX_SYSCFG0_VIRT(DA8XX_CFGCHIP2_REG));
 		if (val & CFGCHIP2_PHYCLKGD)
-			return;
+			goto done;
 		udelay(1);
 	}
 
 	pr_err("Timeout waiting for USB 2.0 PHY clock good.\n");
+done:
+	clk_disable_unprepare(usb20_clk);
+	clk_put(usb20_clk);
 }
 
 static void usb20_phy_clk_disable(struct clk *clk)
-- 
2.7.1