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

From: Weilong Chen
Date: Wed Sep 21 2022 - 06:14:11 EST


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@xxxxxxxxxx>
---
drivers/i2c/busses/i2c-hisi.c | 25 ++++++++++++++++++++-----
1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/drivers/i2c/busses/i2c-hisi.c b/drivers/i2c/busses/i2c-hisi.c
index 67031024217c..5e48d4ee0c6d 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>
@@ -91,6 +92,7 @@ struct hisi_i2c_controller {
void __iomem *iobase;
struct device *dev;
int irq;
+ struct clk *clk;

/* Intermediates for recording the transfer process */
struct completion *completion;
@@ -456,10 +458,21 @@ 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(&pdev->dev, NULL);
+ if (IS_ERR(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 {
+ ret = clk_prepare_enable(ctlr->clk);
+ if (ret) {
+ dev_err(dev, "failed to enable clock, ret = %d\n", ret);
+ return ret;
+ }
+
+ clk_rate_hz = clk_get_rate(ctlr->clk);
}

ctlr->clk_rate_khz = DIV_ROUND_UP_ULL(clk_rate_hz, HZ_PER_KHZ);
@@ -475,8 +488,10 @@ static int hisi_i2c_probe(struct platform_device *pdev)
i2c_set_adapdata(adapter, ctlr);

ret = devm_i2c_add_adapter(dev, adapter);
- if (ret)
+ if (ret) {
+ clk_disable_unprepare(ctlr->clk);
return ret;
+ }

hw_version = readl(ctlr->iobase + HISI_I2C_VERSION);
dev_info(ctlr->dev, "speed mode is %s. hw version 0x%x\n",
--
2.31.GIT