Re: [PATCH 04/12] i2c: riic: Use pm_runtime_resume_and_get()

claudiu beznea
2024-06-21T12:49:20Z

Hi, Biju,

On 21.06.2024 15:24, Biju Das wrote:
> Hi Claudiu,
>
> Thanks for the patch.
>
>> -----Original Message-----
>> From: Claudiu <claudiu.beznea@tuxon.dev>
>> Sent: Friday, June 21, 2024 12:23 PM
>> Subject: [PATCH 04/12] i2c: riic: Use pm_runtime_resume_and_get()
>>
>> From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>>
>> pm_runtime_get_sync() may return with error. In case it returns with error
>> dev->power.usage_count needs to be decremented.
>> dev->pm_runtime_resume_and_get()
>> takes care of this. Thus use it.
>>
>> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>> ---
>> drivers/i2c/busses/i2c-riic.c | 25 +++++++++++++++++++++----
>> 1 file changed, 21 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/i2c/busses/i2c-riic.c b/drivers/i2c/busses/i2c-riic.c index
>> 83e4d5e14ab6..6b739483ef37 100644
>> --- a/drivers/i2c/busses/i2c-riic.c
>> +++ b/drivers/i2c/busses/i2c-riic.c
>> @@ -113,6 +113,8 @@ struct riic_irq_desc {
>> char *name;
>> };
>>
>> +static const char * const riic_rpm_err_msg = "Failed to runtime
>> +resume";
>> +
>> static inline void riic_writeb(struct riic_dev *riic, u8 val, u8 offset) {
>> writeb(val, riic->base + riic->info->regs[offset]); @@ -133,10 +135,14 @@ static int
>> riic_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
>> struct riic_dev *riic = i2c_get_adapdata(adap);
>> struct device *dev = adap->dev.parent;
>> unsigned long time_left;
>> - int i;
>> + int i, ret;
>> u8 start_bit;
>>
>> - pm_runtime_get_sync(dev);
>> + ret = pm_runtime_resume_and_get(dev);
>> + if (ret) {
>> + dev_err(dev, riic_rpm_err_msg);
>> + return ret;
>> + }
>>
>> if (riic_readb(riic, RIIC_ICCR2) & ICCR2_BBSY) {
>> riic->err = -EBUSY;
>> @@ -301,6 +307,7 @@ static const struct i2c_algorithm riic_algo = {
>>
>> static int riic_init_hw(struct riic_dev *riic, struct i2c_timings *t) {
>> + int ret;
>> unsigned long rate;
>> int total_ticks, cks, brl, brh;
>> struct device *dev = riic->adapter.dev.parent; @@ -379,7 +386,11 @@ static int
>> riic_init_hw(struct riic_dev *riic, struct i2c_timings *t)
>> t->scl_fall_ns / (1000000000 / rate),
>> t->scl_rise_ns / (1000000000 / rate), cks, brl, brh);
>>
>> - pm_runtime_get_sync(dev);
>> + ret = pm_runtime_resume_and_get(dev);
>> + if (ret) {
>> + dev_err(dev, riic_rpm_err_msg);
>> + return ret;
>> + }
>>
>> /* Changing the order of accessing IICRST and ICE may break things! */
>> riic_writeb(riic, ICCR1_IICRST | ICCR1_SOWP, RIIC_ICCR1); @@ -498,8 +509,14 @@ static void
>> riic_i2c_remove(struct platform_device *pdev) {
>> struct riic_dev *riic = platform_get_drvdata(pdev);
>> struct device *dev = &pdev->dev;
>> + int ret;
>> +
>> + ret = pm_runtime_resume_and_get(dev);
>> + if (ret) {
>> + dev_err(dev, riic_rpm_err_msg);
>> + return;
>> + }
>
> This change will lead to resource leak. Maybe if there is error
> skip accessing the register. Or restore previous code,
> just ignore condition in remove.

Ok, I'll delete the adapter.

>
> There are other place in i2c core driver where this call can fail.
> You could fix as well.
> https://elixir.bootlin.com/linux/v6.10-rc4/source/drivers/i2c/i2c-core-base.c#L509

Yes, there are many other places as well. Wolfram, would you prefer
touching that code, as well?

Thank you,
Claudiu Beznea

>
> Cheers,
> Biju
>
>>
>> - pm_runtime_get_sync(dev);
>> riic_writeb(riic, 0, RIIC_ICIER);
>> pm_runtime_put(dev);
>> i2c_del_adapter(&riic->adapter);
>> --
>> 2.39.2
>>
>