netdev - [PATCH 16/25] net: stmmac: Use optional clock request method to get ptp

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Date:   Mon, 14 Dec 2020 12:16:06 +0300
From:   Serge Semin <Sergey.Semin@...kalelectronics.ru>
To:     Rob Herring <robh+dt@...nel.org>,
        Giuseppe Cavallaro <peppe.cavallaro@...com>,
        Alexandre Torgue <alexandre.torgue@...com>,
        Jose Abreu <joabreu@...opsys.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Johan Hovold <johan@...nel.org>,
        Maxime Ripard <mripard@...nel.org>,
        Joao Pinto <jpinto@...opsys.com>,
        Lars Persson <larper@...s.com>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>
CC:     Serge Semin <Sergey.Semin@...kalelectronics.ru>,
        Serge Semin <fancer.lancer@...il.com>,
        Alexey Malahov <Alexey.Malahov@...kalelectronics.ru>,
        Pavel Parkhomenko <Pavel.Parkhomenko@...kalelectronics.ru>,
        Vyacheslav Mitrofanov 
        <Vyacheslav.Mitrofanov@...kalelectronics.ru>,
        <netdev@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH 16/25] net: stmmac: Use optional clock request method to get ptp_clk

Let's replace the manual implementation of the optional ptp_clk
functionality with method devm_clk_get_optional() provided by the common
clock kernel framework. First of all it will be better from
maintainability point of view. Secondly by doing so we'll also fix a
potential problem, which will come out if the PTP clock has been actually
specified, but the clock framework failed to request it.

Note since we are switching the code to using the optional common clock
API, then there is no need in checking the clk_ptp_ref pointer for being
not NULL before calling the clk_prepare_enable() method. The later will
correctly handle it. So just discard the conditional statement of
priv->plat->clk_ptp_ref pointer value testing in the stmmac_resume()
method.

Signed-off-by: Serge Semin <Sergey.Semin@...kalelectronics.ru>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c     | 3 +--
 drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c | 7 +++++--
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 13681027dd09..e9003684efc8 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -5230,8 +5230,7 @@ int stmmac_resume(struct device *dev)
 		/* enable the clk previously disabled */
 		clk_prepare_enable(priv->plat->stmmac_clk);
 		clk_prepare_enable(priv->plat->pclk);
-		if (priv->plat->clk_ptp_ref)
-			clk_prepare_enable(priv->plat->clk_ptp_ref);
+		clk_prepare_enable(priv->plat->clk_ptp_ref);
 		/* reset the phy so that it's ready */
 		if (priv->mii)
 			stmmac_mdio_reset(priv->mii);
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
index 3809b00d3077..367d1458d66d 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
@@ -589,10 +589,13 @@ stmmac_probe_config_dt(struct platform_device *pdev, const char **mac)
 	clk_prepare_enable(plat->pclk);
 
 	/* Fall-back to main clock in case of no PTP ref is passed */
-	plat->clk_ptp_ref = devm_clk_get(&pdev->dev, "ptp_ref");
+	plat->clk_ptp_ref = devm_clk_get_optional(&pdev->dev, "ptp_ref");
 	if (IS_ERR(plat->clk_ptp_ref)) {
+		rc = PTR_ERR(plat->clk_ptp_ref);
+		dev_err_probe(&pdev->dev, rc, "Cannot get PTP clock\n");
+		goto error_hw_init;
+	} else if (!plat->clk_ptp_ref) {
 		plat->clk_ptp_rate = clk_get_rate(plat->stmmac_clk);
-		plat->clk_ptp_ref = NULL;
 		dev_info(&pdev->dev, "PTP uses main clock\n");
 	} else {
 		plat->clk_ptp_rate = clk_get_rate(plat->clk_ptp_ref);
-- 
2.29.2