linux-kernel - [PATCH v7 04/14] sata: ahci-da850: get the sata clock using a connection id

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Message-Id: <1485770531-6772-5-git-send-email-bgolaszewski@baylibre.com>
Date:   Mon, 30 Jan 2017 11:02:01 +0100
From:   Bartosz Golaszewski <bgolaszewski@...libre.com>
To:     Kevin Hilman <khilman@...nel.org>, Sekhar Nori <nsekhar@...com>,
        Patrick Titiano <ptitiano@...libre.com>,
        Michael Turquette <mturquette@...libre.com>,
        Tejun Heo <tj@...nel.org>, Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Russell King <linux@...linux.org.uk>,
        David Lechner <david@...hnology.com>
Cc:     linux-ide@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        Bartosz Golaszewski <bgolaszewski@...libre.com>
Subject: [PATCH v7 04/14] sata: ahci-da850: get the sata clock using a connection id

In preparation for using two clocks in the driver (the sysclk2-based
clock and the external REFCLK), check if we got the functional clock
after calling ahci_platform_get_resources(). If not, retry calling
clk_get() with con_id specified.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@...libre.com>
Acked-by: Tejun Heo <tj@...nel.org>
---
 drivers/ata/ahci_da850.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/ata/ahci_da850.c b/drivers/ata/ahci_da850.c
index 267a3d3..e397bab 100644
--- a/drivers/ata/ahci_da850.c
+++ b/drivers/ata/ahci_da850.c
@@ -71,12 +71,28 @@ static int ahci_da850_probe(struct platform_device *pdev)
 	struct ahci_host_priv *hpriv;
 	struct resource *res;
 	void __iomem *pwrdn_reg;
+	struct clk *clk;
 	int rc;
 
 	hpriv = ahci_platform_get_resources(pdev);
 	if (IS_ERR(hpriv))
 		return PTR_ERR(hpriv);
 
+	/*
+	 * Internally ahci_platform_get_resources() calls clk_get(dev, NULL)
+	 * when trying to obtain the functional clock. This SATA controller
+	 * uses two clocks for which we specify two connection ids. If we don't
+	 * have the functional clock at this point - call clk_get() again with
+	 * con_id = "fck".
+	 */
+	if (!hpriv->clks[0]) {
+		clk = clk_get(dev, "fck");
+		if (IS_ERR(clk))
+			return PTR_ERR(clk);
+
+		hpriv->clks[0] = clk;
+	}
+
 	rc = ahci_platform_enable_resources(hpriv);
 	if (rc)
 		return rc;
-- 
2.9.3