[V2][PATCH 1/5] spi: spi-zynqmp-gqspi: fix clk_enable/disable imbalance issue

From: quanyang.wang@windriver.com
To: Mark Brown <broonie@kernel.org>,
	Michal Simek <michal.simek@xilinx.com>,
	Amit Kumar Mahapatra <amit.kumar-mahapatra@xilinx.com>
Cc: linux-spi@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	Quanyang Wang <quanyang.wang@windriver.com>
Subject: [V2][PATCH 1/5] spi: spi-zynqmp-gqspi: fix clk_enable/disable imbalance issue
Date: Fri, 16 Apr 2021 22:20:43 +0800	[thread overview]
Message-ID: <20210416142047.6349-2-quanyang.wang@windriver.com> (raw)
In-Reply-To: <20210416142047.6349-1-quanyang.wang@windriver.com>

From: Quanyang Wang <quanyang.wang@windriver.com>

The clks "pclk" and "ref_clk" are enabled twice during the probe. The
first time is in the function zynqmp_qspi_probe and the second time is
in zynqmp_qspi_setup_op which is called by devm_spi_register_controller.
Then calling zynqmp_qspi_remove (rmmod this module) to disable these clks
will trigger a warning as below:

[  309.124604] Unpreparing enabled qspi_ref
[  309.128641] WARNING: CPU: 1 PID: 537 at drivers/clk/clk.c:824 clk_core_unprepare+0x108/0x110

Since pm_runtime works now, clks can be enabled/disabled by calling
zynqmp_runtime_suspend/resume. So we don't need to enable these clks
explicitly in zynqmp_qspi_setup_op. Remove them to fix this issue.

And remove clk enabling/disabling in zynqmp_qspi_resume because there is
no spi transfer operation so enabling ref_clk is redundant meanwhile pclk
is not disabled for it is shared with other peripherals.

Furthermore replace clk_enable/disable with clk_prepare_enable and
clk_disable_unprepare in runtime_suspend/resume functions.

Signed-off-by: Quanyang Wang <quanyang.wang@windriver.com>
---
 drivers/spi/spi-zynqmp-gqspi.c | 47 ++++++----------------------------
 1 file changed, 8 insertions(+), 39 deletions(-)

diff --git a/drivers/spi/spi-zynqmp-gqspi.c b/drivers/spi/spi-zynqmp-gqspi.c
index 32e53f379e9b..f9056f0a480c 100644
--- a/drivers/spi/spi-zynqmp-gqspi.c
+++ b/drivers/spi/spi-zynqmp-gqspi.c
@@ -487,24 +487,10 @@ static int zynqmp_qspi_setup_op(struct spi_device *qspi)
 {
 	struct spi_controller *ctlr = qspi->master;
 	struct zynqmp_qspi *xqspi = spi_controller_get_devdata(ctlr);
-	struct device *dev = &ctlr->dev;
-	int ret;
 
 	if (ctlr->busy)
 		return -EBUSY;
 
-	ret = clk_enable(xqspi->refclk);
-	if (ret) {
-		dev_err(dev, "Cannot enable device clock.\n");
-		return ret;
-	}
-
-	ret = clk_enable(xqspi->pclk);
-	if (ret) {
-		dev_err(dev, "Cannot enable APB clock.\n");
-		clk_disable(xqspi->refclk);
-		return ret;
-	}
 	zynqmp_gqspi_write(xqspi, GQSPI_EN_OFST, GQSPI_EN_MASK);
 
 	return 0;
@@ -863,26 +849,9 @@ static int __maybe_unused zynqmp_qspi_suspend(struct device *dev)
 static int __maybe_unused zynqmp_qspi_resume(struct device *dev)
 {
 	struct spi_controller *ctlr = dev_get_drvdata(dev);
-	struct zynqmp_qspi *xqspi = spi_controller_get_devdata(ctlr);
-	int ret = 0;
-
-	ret = clk_enable(xqspi->pclk);
-	if (ret) {
-		dev_err(dev, "Cannot enable APB clock.\n");
-		return ret;
-	}
-
-	ret = clk_enable(xqspi->refclk);
-	if (ret) {
-		dev_err(dev, "Cannot enable device clock.\n");
-		clk_disable(xqspi->pclk);
-		return ret;
-	}
 
 	spi_controller_resume(ctlr);
 
-	clk_disable(xqspi->refclk);
-	clk_disable(xqspi->pclk);
 	return 0;
 }
 
@@ -898,8 +867,8 @@ static int __maybe_unused zynqmp_runtime_suspend(struct device *dev)
 {
 	struct zynqmp_qspi *xqspi = (struct zynqmp_qspi *)dev_get_drvdata(dev);
 
-	clk_disable(xqspi->refclk);
-	clk_disable(xqspi->pclk);
+	clk_disable_unprepare(xqspi->refclk);
+	clk_disable_unprepare(xqspi->pclk);
 
 	return 0;
 }
@@ -917,16 +886,16 @@ static int __maybe_unused zynqmp_runtime_resume(struct device *dev)
 	struct zynqmp_qspi *xqspi = (struct zynqmp_qspi *)dev_get_drvdata(dev);
 	int ret;
 
-	ret = clk_enable(xqspi->pclk);
+	ret = clk_prepare_enable(xqspi->pclk);
 	if (ret) {
 		dev_err(dev, "Cannot enable APB clock.\n");
 		return ret;
 	}
 
-	ret = clk_enable(xqspi->refclk);
+	ret = clk_prepare_enable(xqspi->refclk);
 	if (ret) {
 		dev_err(dev, "Cannot enable device clock.\n");
-		clk_disable(xqspi->pclk);
+		clk_disable_unprepare(xqspi->pclk);
 		return ret;
 	}
 
@@ -1136,13 +1105,11 @@ static int zynqmp_qspi_probe(struct platform_device *pdev)
 		goto remove_master;
 	}
 
-	init_completion(&xqspi->data_completion);
-
 	xqspi->refclk = devm_clk_get(&pdev->dev, "ref_clk");
 	if (IS_ERR(xqspi->refclk)) {
 		dev_err(dev, "ref_clk clock not found.\n");
 		ret = PTR_ERR(xqspi->refclk);
-		goto clk_dis_pclk;
+		goto remove_master;
 	}
 
 	ret = clk_prepare_enable(xqspi->pclk);
@@ -1157,6 +1124,8 @@ static int zynqmp_qspi_probe(struct platform_device *pdev)
 		goto clk_dis_pclk;
 	}
 
+	init_completion(&xqspi->data_completion);
+
 	mutex_init(&xqspi->op_lock);
 
 	pm_runtime_use_autosuspend(&pdev->dev);
-- 
2.25.1

