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From: Jerome Brunet <jbrunet@baylibre.com>
To: Wolfram Sang <wsa@kernel.org>, Kevin Hilman <khilman@baylibre.com>
Cc: linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org,
	linux-i2c@vger.kernel.org, Nicolas Belin <nbelin@baylibre.com>,
	Jerome Brunet <jbrunet@baylibre.com>
Subject: [PATCH 2/3] i2c: meson: keep peripheral clock enabled
Date: Wed,  7 Oct 2020 10:07:50 +0200	[thread overview]
Message-ID: <20201007080751.1259442-3-jbrunet@baylibre.com> (raw)
In-Reply-To: <20201007080751.1259442-1-jbrunet@baylibre.com>

SCL rate appears to be different than what is expected. For example,
We get 164kHz on i2c3 of the vim3 when 400kHz is expected. This is
partially due to the peripheral clock being disabled when the clock is
set.

Let's keep the peripheral clock on after probe to fix the problem. This
does not affect the SCL output which is still gated when i2c is idle.

Fixes: 09af1c2fa490 ("i2c: meson: set clock divider in probe instead of setting it for each transfer")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
---
 drivers/i2c/busses/i2c-meson.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/drivers/i2c/busses/i2c-meson.c b/drivers/i2c/busses/i2c-meson.c
index dac0d2a00cec..e7ec2ab2a220 100644
--- a/drivers/i2c/busses/i2c-meson.c
+++ b/drivers/i2c/busses/i2c-meson.c
@@ -370,16 +370,12 @@ static int meson_i2c_xfer_messages(struct i2c_adapter *adap,
 	struct meson_i2c *i2c = adap->algo_data;
 	int i, ret = 0;
 
-	clk_enable(i2c->clk);
-
 	for (i = 0; i < num; i++) {
 		ret = meson_i2c_xfer_msg(i2c, msgs + i, i == num - 1, atomic);
 		if (ret)
 			break;
 	}
 
-	clk_disable(i2c->clk);
-
 	return ret ?: i;
 }
 
@@ -448,7 +444,7 @@ static int meson_i2c_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	ret = clk_prepare(i2c->clk);
+	ret = clk_prepare_enable(i2c->clk);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "can't prepare clock\n");
 		return ret;
@@ -470,7 +466,7 @@ static int meson_i2c_probe(struct platform_device *pdev)
 
 	ret = i2c_add_adapter(&i2c->adap);
 	if (ret < 0) {
-		clk_unprepare(i2c->clk);
+		clk_disable_unprepare(i2c->clk);
 		return ret;
 	}
 
@@ -488,7 +484,7 @@ static int meson_i2c_remove(struct platform_device *pdev)
 	struct meson_i2c *i2c = platform_get_drvdata(pdev);
 
 	i2c_del_adapter(&i2c->adap);
-	clk_unprepare(i2c->clk);
+	clk_disable_unprepare(i2c->clk);
 
 	return 0;
 }
-- 
2.25.4


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  parent reply	other threads:[~2020-10-07  8:08 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-07  8:07 [PATCH 0/3] i2c: meson: scl rate fixups Jerome Brunet
2020-10-07  8:07 ` [PATCH 1/3] i2c: meson: fix clock setting overwrite Jerome Brunet
2020-10-08  9:59   ` Wolfram Sang
2020-10-07  8:07 ` Jerome Brunet [this message]
2020-10-08 10:00   ` [PATCH 2/3] i2c: meson: keep peripheral clock enabled Wolfram Sang
2020-10-07  8:07 ` [PATCH 3/3] i2c: meson: fixup rate calculation with filter delay Jerome Brunet
2020-10-08 10:00   ` Wolfram Sang

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