diff mbox series

[v3,3/3] i2c: rk3x: Add check for clk_enable()

Message ID 20241107211428.32273-3-jiashengjiangcool@gmail.com
State New
Headers show
Series [v3,1/3] i2c: lpc2k: Add check for clk_enable() | expand

Commit Message

Jiasheng Jiang Nov. 7, 2024, 9:14 p.m. UTC 
Add check for the return value of clk_enable() in order to catch the
potential exception. Moreover, convert the return type of
rk3x_i2c_adapt_div() into int and add the check.

Signed-off-by: Jiasheng Jiang <jiashengjiangcool@gmail.com>
---
Changelog:

v2 -> v3:

1. Roll back unsuitable dev_err_probe() to dev_err()

v1 -> v2:

1. Remove the Fixes tag.
2. Use dev_err_probe to simplify error handling.
---
 drivers/i2c/busses/i2c-rk3x.c | 55 ++++++++++++++++++++++++++---------
 1 file changed, 41 insertions(+), 14 deletions(-)

Comments

Andi Shyti Nov. 13, 2024, 10:24 p.m. UTC | #1 
Hi Jiasheng,

On Thu, Nov 07, 2024 at 09:14:28PM +0000, Jiasheng Jiang wrote:
> Add check for the return value of clk_enable() in order to catch the
> potential exception. Moreover, convert the return type of

It's more an "unlikely exception" rather than a "potential
exeption".

> rk3x_i2c_adapt_div() into int and add the check.

...

>  static u32 rk3x_i2c_func(struct i2c_adapter *adap)
> @@ -1365,9 +1389,12 @@ static int rk3x_i2c_probe(struct platform_device *pdev)
>  	}
>  
>  	clk_rate = clk_get_rate(i2c->clk);
> -	rk3x_i2c_adapt_div(i2c, clk_rate);
> +	ret = rk3x_i2c_adapt_div(i2c, clk_rate);
>  	clk_disable(i2c->clk);

you can't disable a clock that has failed to enable, right?

BTW, although I like this patch (or at least I don't dislike), I
still want to check whether it's wanted or not.

Andi

>  
> +	if (ret)
> +		goto err_clk_notifier;
> +
>  	ret = i2c_add_adapter(&i2c->adap);
>  	if (ret < 0)
>  		goto err_clk_notifier;
> -- 
> 2.25.1
>
Jiasheng Jiang Nov. 14, 2024, 8:56 p.m. UTC | #2 
On Wed, Nov 13, 2024 at 5:24 PM Andi Shyti <andi.shyti@kernel.org> wrote:
>
> Hi Jiasheng,
>
> On Thu, Nov 07, 2024 at 09:14:28PM +0000, Jiasheng Jiang wrote:
> > Add check for the return value of clk_enable() in order to catch the
> > potential exception. Moreover, convert the return type of
>
> It's more an "unlikely exception" rather than a "potential
> exeption".
>
> > rk3x_i2c_adapt_div() into int and add the check.
>
> ...
>
> >  static u32 rk3x_i2c_func(struct i2c_adapter *adap)
> > @@ -1365,9 +1389,12 @@ static int rk3x_i2c_probe(struct platform_device *pdev)
> >       }
> >
> >       clk_rate = clk_get_rate(i2c->clk);
> > -     rk3x_i2c_adapt_div(i2c, clk_rate);
> > +     ret = rk3x_i2c_adapt_div(i2c, clk_rate);
> >       clk_disable(i2c->clk);
>
> you can't disable a clock that has failed to enable, right?
>
> BTW, although I like this patch (or at least I don't dislike), I
> still want to check whether it's wanted or not.
>
> Andi
>

Thank you for your advice. I have carefully reviewed the patch.
There are two clocks: "i2c->clk" and "i2c->pclk".
The "i2c->clk" is enabled and disabled in rk3x_i2c_probe(),
while the "i2c->pclk" is managed within rk3x_i2c_adapt_div().
Thus, the "i2c->clk" has already been enabled at this point.

-Jiasheng


> >
> > +     if (ret)
> > +             goto err_clk_notifier;
> > +
> >       ret = i2c_add_adapter(&i2c->adap);
> >       if (ret < 0)
> >               goto err_clk_notifier;
> > --
> > 2.25.1
> >
diff mbox series

Patch

diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c
index 4ef9bad77b85..0263ee0e0470 100644
--- a/drivers/i2c/busses/i2c-rk3x.c
+++ b/drivers/i2c/busses/i2c-rk3x.c
@@ -871,7 +871,7 @@  static int rk3x_i2c_v1_calc_timings(unsigned long clk_rate,
 	return ret;
 }
 
-static void rk3x_i2c_adapt_div(struct rk3x_i2c *i2c, unsigned long clk_rate)
+static int rk3x_i2c_adapt_div(struct rk3x_i2c *i2c, unsigned long clk_rate)
 {
 	struct i2c_timings *t = &i2c->t;
 	struct rk3x_i2c_calced_timings calc;
@@ -883,7 +883,11 @@  static void rk3x_i2c_adapt_div(struct rk3x_i2c *i2c, unsigned long clk_rate)
 	ret = i2c->soc_data->calc_timings(clk_rate, t, &calc);
 	WARN_ONCE(ret != 0, "Could not reach SCL freq %u", t->bus_freq_hz);
 
-	clk_enable(i2c->pclk);
+	ret = clk_enable(i2c->pclk);
+	if (ret) {
+		dev_err(i2c->dev, "Can't enable bus clk for rk3399: %d\n", ret);
+		return ret;
+	}
 
 	spin_lock_irqsave(&i2c->lock, flags);
 	val = i2c_readl(i2c, REG_CON);
@@ -904,6 +908,8 @@  static void rk3x_i2c_adapt_div(struct rk3x_i2c *i2c, unsigned long clk_rate)
 		clk_rate / 1000,
 		1000000000 / t->bus_freq_hz,
 		t_low_ns, t_high_ns);
+
+	return 0;
 }
 
 /**
@@ -942,19 +948,27 @@  static int rk3x_i2c_clk_notifier_cb(struct notifier_block *nb, unsigned long
 			return NOTIFY_STOP;
 
 		/* scale up */
-		if (ndata->new_rate > ndata->old_rate)
-			rk3x_i2c_adapt_div(i2c, ndata->new_rate);
+		if (ndata->new_rate > ndata->old_rate) {
+			if (rk3x_i2c_adapt_div(i2c, ndata->new_rate))
+				return NOTIFY_STOP;
+		}
 
 		return NOTIFY_OK;
 	case POST_RATE_CHANGE:
 		/* scale down */
-		if (ndata->new_rate < ndata->old_rate)
-			rk3x_i2c_adapt_div(i2c, ndata->new_rate);
+		if (ndata->new_rate < ndata->old_rate) {
+			if (rk3x_i2c_adapt_div(i2c, ndata->new_rate))
+				return NOTIFY_STOP;
+		}
+
 		return NOTIFY_OK;
 	case ABORT_RATE_CHANGE:
 		/* scale up */
-		if (ndata->new_rate > ndata->old_rate)
-			rk3x_i2c_adapt_div(i2c, ndata->old_rate);
+		if (ndata->new_rate > ndata->old_rate) {
+			if (rk3x_i2c_adapt_div(i2c, ndata->old_rate))
+				return NOTIFY_STOP;
+		}
+
 		return NOTIFY_OK;
 	default:
 		return NOTIFY_DONE;
@@ -1068,8 +1082,20 @@  static int rk3x_i2c_xfer_common(struct i2c_adapter *adap,
 
 	spin_lock_irqsave(&i2c->lock, flags);
 
-	clk_enable(i2c->clk);
-	clk_enable(i2c->pclk);
+	ret = clk_enable(i2c->clk);
+	if (ret) {
+		spin_unlock_irqrestore(&i2c->lock, flags);
+		dev_err(i2c->dev, "Can't enable bus clk: %d\n", ret);
+		return ret;
+	}
+
+	ret = clk_enable(i2c->pclk);
+	if (ret) {
+		clk_disable(i2c->clk);
+		spin_unlock_irqrestore(&i2c->lock, flags);
+		dev_err(i2c->dev, "Can't enable bus clk for rk3399: %d\n", ret);
+		return ret;
+	}
 
 	i2c->is_last_msg = false;
 
@@ -1149,9 +1175,7 @@  static __maybe_unused int rk3x_i2c_resume(struct device *dev)
 {
 	struct rk3x_i2c *i2c = dev_get_drvdata(dev);
 
-	rk3x_i2c_adapt_div(i2c, clk_get_rate(i2c->clk));
-
-	return 0;
+	return rk3x_i2c_adapt_div(i2c, clk_get_rate(i2c->clk));
 }
 
 static u32 rk3x_i2c_func(struct i2c_adapter *adap)
@@ -1365,9 +1389,12 @@  static int rk3x_i2c_probe(struct platform_device *pdev)
 	}
 
 	clk_rate = clk_get_rate(i2c->clk);
-	rk3x_i2c_adapt_div(i2c, clk_rate);
+	ret = rk3x_i2c_adapt_div(i2c, clk_rate);
 	clk_disable(i2c->clk);
 
+	if (ret)
+		goto err_clk_notifier;
+
 	ret = i2c_add_adapter(&i2c->adap);
 	if (ret < 0)
 		goto err_clk_notifier;