[PATCH next v3] i2c: hisi: Add support to get clock frequency from clock property

[PATCH next v3] i2c: hisi: Add support to get clock frequency from clock property

[Weilong Chen]

Support the driver to obtain clock information by clk_rate or
clock property. Find clock first, if not, fall back to clk_rate.

Signed-off-by: Weilong Chen <chenweilong@huawei.com>
Acked-by: Yicong Yang <yangyicong@hisilicon.com>
---
Change since v1:
- Ordered struct field to inverted triangle.
- Use devm_clk_get_optional_enabled().
- Use IS_ERR_OR_NULL.
Link: https://lore.kernel.org/lkml/20220921101540.352553-1-chenweilong@huawei.com/

Change since v2:
- Remove redundant blank line
Link: https://lore.kernel.org/all/20220923011417.78994-1-chenweilong@huawei.com/

 drivers/i2c/busses/i2c-hisi.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-hisi.c b/drivers/i2c/busses/i2c-hisi.c
index 67031024217c..e4b0ebe54f6f 100644
--- a/drivers/i2c/busses/i2c-hisi.c
+++ b/drivers/i2c/busses/i2c-hisi.c
@@ -8,6 +8,7 @@
 #include <linux/acpi.h>
 #include <linux/bits.h>
 #include <linux/bitfield.h>
+#include <linux/clk.h>
 #include <linux/completion.h>
 #include <linux/i2c.h>
 #include <linux/interrupt.h>
@@ -90,6 +91,7 @@ struct hisi_i2c_controller {
 	struct i2c_adapter adapter;
 	void __iomem *iobase;
 	struct device *dev;
+	struct clk *clk;
 	int irq;
 
 	/* Intermediates for recording the transfer process */
@@ -456,10 +458,15 @@ static int hisi_i2c_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	ret = device_property_read_u64(dev, "clk_rate", &clk_rate_hz);
-	if (ret) {
-		dev_err(dev, "failed to get clock frequency, ret = %d\n", ret);
-		return ret;
+	ctlr->clk = devm_clk_get_optional_enabled(&pdev->dev, NULL);
+	if (IS_ERR_OR_NULL(ctlr->clk)) {
+		ret = device_property_read_u64(dev, "clk_rate", &clk_rate_hz);
+		if (ret) {
+			dev_err(dev, "failed to get clock frequency, ret = %d\n", ret);
+			return ret;
+		}
+	} else {
+		clk_rate_hz = clk_get_rate(ctlr->clk);
 	}
 
 	ctlr->clk_rate_khz = DIV_ROUND_UP_ULL(clk_rate_hz, HZ_PER_KHZ);
-- 
2.31.GIT

Re: [PATCH next v3] i2c: hisi: Add support to get clock frequency from clock property

[Wolfram Sang]

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On Mon, Sep 26, 2022 at 05:15:03PM +0800, Weilong Chen wrote:
> Support the driver to obtain clock information by clk_rate or
> clock property. Find clock first, if not, fall back to clk_rate.

This commit message describes what the patch does. But it misses the
explanation why this needs to be done. Could you add this information,
please? Patch itself looks also good to me.

> 
> Signed-off-by: Weilong Chen <chenweilong@huawei.com>
> Acked-by: Yicong Yang <yangyicong@hisilicon.com>

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Re: [PATCH next v3] i2c: hisi: Add support to get clock frequency from clock property

[chenweilong]

On 2022/9/29 3:52, Wolfram Sang wrote:
> On Mon, Sep 26, 2022 at 05:15:03PM +0800, Weilong Chen wrote:
>> Support the driver to obtain clock information by clk_rate or
>> clock property. Find clock first, if not, fall back to clk_rate.
> This commit message describes what the patch does. But it misses the
> explanation why this needs to be done. Could you add this information,
> please? Patch itself looks also good to me.

OK, I'll update it.

Thanks.

>> Signed-off-by: Weilong Chen <chenweilong@huawei.com>
>> Acked-by: Yicong Yang <yangyicong@hisilicon.com>