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SubjectRe: [PATCH V5 3/3] i2c: i2c-qcom-geni: Add shutdown callback for i2c
Hi Stephen,

On 2020-10-03 07:09, Stephen Boyd wrote:
> Quoting Roja Rani Yarubandi (2020-10-01 01:44:25)
>> diff --git a/drivers/i2c/busses/i2c-qcom-geni.c
>> b/drivers/i2c/busses/i2c-qcom-geni.c
>> index aee2a1dd2c62..56d3fbfe7eb6 100644
>> --- a/drivers/i2c/busses/i2c-qcom-geni.c
>> +++ b/drivers/i2c/busses/i2c-qcom-geni.c
>> @@ -380,6 +380,36 @@ static void geni_i2c_tx_msg_cleanup(struct
>> geni_i2c_dev *gi2c,
>> }
>> }
>>
>> +static void geni_i2c_stop_xfer(struct geni_i2c_dev *gi2c)
>> +{
>> + int ret;
>> + u32 geni_status;
>> + unsigned long flags;
>> + struct i2c_msg *cur;
>> +
>> + /* Resume device, runtime suspend can happen anytime during
>> transfer */
>> + ret = pm_runtime_get_sync(gi2c->se.dev);
>> + if (ret < 0) {
>> + dev_err(gi2c->se.dev, "Failed to resume device: %d\n",
>> ret);
>> + return;
>> + }
>> +
>> + spin_lock_irqsave(&gi2c->lock, flags);
>
> We grab the lock here.
>
>> + geni_status = readl_relaxed(gi2c->se.base + SE_GENI_STATUS);
>> + if (!(geni_status & M_GENI_CMD_ACTIVE))
>> + goto out;
>> +
>> + cur = gi2c->cur;
>> + geni_i2c_abort_xfer(gi2c);
>
> But it looks like this function takes the lock again? Did you test this
> with lockdep enabled? It should hang even without lockdep, so it seems
> like this path of code has not been tested.
>

Tested with lockdep enabled, and fixed the unsafe lock order issue here.
And to be more proper moved spin_lock/unlock to cleanup functions.

>> + if (cur->flags & I2C_M_RD)
>> + geni_i2c_rx_msg_cleanup(gi2c, cur);
>> + else
>> + geni_i2c_tx_msg_cleanup(gi2c, cur);
>> + spin_unlock_irqrestore(&gi2c->lock, flags);
>> +out:
>> + pm_runtime_put_sync_suspend(gi2c->se.dev);
>> +}
>> +
>> static int geni_i2c_rx_one_msg(struct geni_i2c_dev *gi2c, struct
>> i2c_msg *msg,
>> u32 m_param)
>> {

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