[PATCH v3 3/6] usb: misc: usb3503: get optional clock by devm_clk_get_optional()

From: Chunfeng Yun
Date: Wed Apr 17 2019 - 04:28:58 EST


When the driver tries to get optional clock, it ignores all errors except
-EPROBE_DEFER, but if only ignores -ENOENT, it will cover some real errors,
such as -ENOMEM, so use devm_clk_get_optional() to get optional clock.
And remove unnecessary stack variable clk.

Cc: Dongjin Kim <tobetter@xxxxxxxxx>
Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
---
v3: modify changelog comment
v2: no changes
---
drivers/usb/misc/usb3503.c | 48 ++++++++++++++------------------------
1 file changed, 18 insertions(+), 30 deletions(-)

diff --git a/drivers/usb/misc/usb3503.c b/drivers/usb/misc/usb3503.c
index d5141aa79dd4..72f39a9751b5 100644
--- a/drivers/usb/misc/usb3503.c
+++ b/drivers/usb/misc/usb3503.c
@@ -172,7 +172,6 @@ static int usb3503_probe(struct usb3503 *hub)
hub->gpio_reset = pdata->gpio_reset;
hub->mode = pdata->initial_mode;
} else if (np) {
- struct clk *clk;
u32 rate = 0;
hub->port_off_mask = 0;

@@ -198,34 +197,29 @@ static int usb3503_probe(struct usb3503 *hub)
}
}

- clk = devm_clk_get(dev, "refclk");
- if (IS_ERR(clk) && PTR_ERR(clk) != -ENOENT) {
+ hub->clk = devm_clk_get_optional(dev, "refclk");
+ if (IS_ERR(hub->clk)) {
dev_err(dev, "unable to request refclk (%ld)\n",
- PTR_ERR(clk));
- return PTR_ERR(clk);
+ PTR_ERR(hub->clk));
+ return PTR_ERR(hub->clk);
}

- if (!IS_ERR(clk)) {
- hub->clk = clk;
-
- if (rate != 0) {
- err = clk_set_rate(hub->clk, rate);
- if (err) {
- dev_err(dev,
- "unable to set reference clock rate to %d\n",
- (int) rate);
- return err;
- }
- }
-
- err = clk_prepare_enable(hub->clk);
+ if (rate != 0) {
+ err = clk_set_rate(hub->clk, rate);
if (err) {
dev_err(dev,
- "unable to enable reference clock\n");
+ "unable to set reference clock rate to %d\n",
+ (int)rate);
return err;
}
}

+ err = clk_prepare_enable(hub->clk);
+ if (err) {
+ dev_err(dev, "unable to enable reference clock\n");
+ return err;
+ }
+
property = of_get_property(np, "disabled-ports", &len);
if (property && (len / sizeof(u32)) > 0) {
int i;
@@ -324,8 +318,7 @@ static int usb3503_i2c_remove(struct i2c_client *i2c)
struct usb3503 *hub;

hub = i2c_get_clientdata(i2c);
- if (hub->clk)
- clk_disable_unprepare(hub->clk);
+ clk_disable_unprepare(hub->clk);

return 0;
}
@@ -348,8 +341,7 @@ static int usb3503_platform_remove(struct platform_device *pdev)
struct usb3503 *hub;

hub = platform_get_drvdata(pdev);
- if (hub->clk)
- clk_disable_unprepare(hub->clk);
+ clk_disable_unprepare(hub->clk);

return 0;
}
@@ -358,18 +350,14 @@ static int usb3503_platform_remove(struct platform_device *pdev)
static int usb3503_suspend(struct usb3503 *hub)
{
usb3503_switch_mode(hub, USB3503_MODE_STANDBY);
-
- if (hub->clk)
- clk_disable_unprepare(hub->clk);
+ clk_disable_unprepare(hub->clk);

return 0;
}

static int usb3503_resume(struct usb3503 *hub)
{
- if (hub->clk)
- clk_prepare_enable(hub->clk);
-
+ clk_prepare_enable(hub->clk);
usb3503_switch_mode(hub, hub->mode);

return 0;
--
2.21.0