linux-kernel - [PATCH v9 05/32] i2c: tegra: Initialize div-clk rate unconditionally

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Message-Id: <20200929221915.10979-6-digetx@gmail.com>
Date:   Wed, 30 Sep 2020 01:18:48 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Laxman Dewangan <ldewangan@...dia.com>,
        Wolfram Sang <wsa@...-dreams.de>,
        Michał Mirosław <mirq-linux@...e.qmqm.pl>,
        Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     linux-i2c@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v9 05/32] i2c: tegra: Initialize div-clk rate unconditionally

It doesn't make sense to conditionalize the div-clk rate changes because
rate is fixed and it won't ever change once it's set at the driver's probe
time. All further changes are NO-OPs because CCF caches rate and skips
rate-change if rate is unchanged.

Reviewed-by: Michał Mirosław <mirq-linux@...e.qmqm.pl>
Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>
Acked-by: Thierry Reding <treding@...dia.com>
Tested-by: Thierry Reding <treding@...dia.com>
Signed-off-by: Dmitry Osipenko <digetx@...il.com>
---
 drivers/i2c/busses/i2c-tegra.c | 34 ++++++++++++++++------------------
 1 file changed, 16 insertions(+), 18 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 1d1ce266255a..720a75439e91 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -293,7 +293,7 @@ struct tegra_i2c_dev {
 	bool is_curr_atomic_xfer;
 };
 
-static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev, bool clk_reinit);
+static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev);
 
 static void dvc_writel(struct tegra_i2c_dev *i2c_dev, u32 val,
 		       unsigned long reg)
@@ -691,7 +691,7 @@ static int __maybe_unused tegra_i2c_runtime_resume(struct device *dev)
 	 * domain ON.
 	 */
 	if (i2c_dev->is_vi) {
-		ret = tegra_i2c_init(i2c_dev, true);
+		ret = tegra_i2c_init(i2c_dev);
 		if (ret)
 			goto disable_div_clk;
 	}
@@ -778,7 +778,7 @@ static void tegra_i2c_vi_init(struct tegra_i2c_dev *i2c_dev)
 	i2c_writel(i2c_dev, 0x0, I2C_TLOW_SEXT);
 }
 
-static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev, bool clk_reinit)
+static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
 {
 	u32 val;
 	int err;
@@ -836,16 +836,14 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev, bool clk_reinit)
 	if (i2c_dev->hw->has_interface_timing_reg && tsu_thd)
 		i2c_writel(i2c_dev, tsu_thd, I2C_INTERFACE_TIMING_1);
 
-	if (!clk_reinit) {
-		clk_multiplier = (tlow + thigh + 2);
-		clk_multiplier *= (i2c_dev->clk_divisor_non_hs_mode + 1);
-		err = clk_set_rate(i2c_dev->div_clk,
-				   i2c_dev->bus_clk_rate * clk_multiplier);
-		if (err) {
-			dev_err(i2c_dev->dev,
-				"failed changing clock rate: %d\n", err);
-			return err;
-		}
+	clk_multiplier  = tlow + thigh + 2;
+	clk_multiplier *= i2c_dev->clk_divisor_non_hs_mode + 1;
+
+	err = clk_set_rate(i2c_dev->div_clk,
+			   i2c_dev->bus_clk_rate * clk_multiplier);
+	if (err) {
+		dev_err(i2c_dev->dev, "failed to set div-clk rate: %d\n", err);
+		return err;
 	}
 
 	if (!i2c_dev->is_dvc && !i2c_dev->is_vi) {
@@ -1319,7 +1317,7 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 
 		if (!time_left && !completion_done(&i2c_dev->dma_complete)) {
 			dev_err(i2c_dev->dev, "DMA transfer timeout\n");
-			tegra_i2c_init(i2c_dev, true);
+			tegra_i2c_init(i2c_dev);
 			return -ETIMEDOUT;
 		}
 
@@ -1340,7 +1338,7 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 
 	if (time_left == 0) {
 		dev_err(i2c_dev->dev, "i2c transfer timed out\n");
-		tegra_i2c_init(i2c_dev, true);
+		tegra_i2c_init(i2c_dev);
 		return -ETIMEDOUT;
 	}
 
@@ -1352,7 +1350,7 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 	if (likely(i2c_dev->msg_err == I2C_ERR_NONE))
 		return 0;
 
-	tegra_i2c_init(i2c_dev, true);
+	tegra_i2c_init(i2c_dev);
 	/* start recovery upon arbitration loss in single master mode */
 	if (i2c_dev->msg_err == I2C_ERR_ARBITRATION_LOST) {
 		if (!i2c_dev->is_multimaster_mode)
@@ -1811,7 +1809,7 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 	if (ret < 0)
 		goto disable_div_clk;
 
-	ret = tegra_i2c_init(i2c_dev, false);
+	ret = tegra_i2c_init(i2c_dev);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to initialize i2c controller\n");
 		goto release_dma;
@@ -1918,7 +1916,7 @@ static int __maybe_unused tegra_i2c_resume(struct device *dev)
 	if (err)
 		return err;
 
-	err = tegra_i2c_init(i2c_dev, false);
+	err = tegra_i2c_init(i2c_dev);
 	if (err)
 		return err;
 
-- 
2.27.0