On Thursday 14 May 2015 02:19 AM, Andrew Morton wrote:
> On Mon, 4 May 2015 14:08:55 +0530 Vignesh R <vigneshr@xxxxxx> wrote:
>
>> This patches makes following changes to omap_hdq driver
>> - Enable 1-wire mode.
>> - Implement w1_triplet callback to facilitate search rom
>> procedure and auto detection of 1-wire slaves.
>> - Proper enabling and disabling of interrupt.
>> - Cleanups (formatting and return value checks).
>>
>> HDQ mode remains unchanged.
>>
>> ...
>>
>> +/*
>> + * W1 triplet callback function - used for searching ROM addresses.
>> + * Registered only when controller is in 1-wire mode.
>> + */
>> +static u8 omap_w1_triplet(void *_hdq, u8 bdir)
>> +{
>> + u8 ret, id_bit, comp_bit;
>> + struct hdq_data *hdq_data = _hdq;
>> + u8 ctrl = OMAP_HDQ_CTRL_STATUS_SINGLE | OMAP_HDQ_CTRL_STATUS_GO |
>> + OMAP_HDQ_CTRL_STATUS_INTERRUPTMASK;
>> + u8 mask = ctrl | OMAP_HDQ_CTRL_STATUS_DIR;
>> +
>> + omap_hdq_get(_hdq);
>> +
>> + ret = mutex_lock_interruptible(&hdq_data->hdq_mutex);
>> + if (ret < 0) {
>> + ret = -EINTR;
>> + goto rtn;
>
> Has this code path been tested? What happens when it is taken? Driver
> initialization fails? If so, why is this desirable behaviour?
The w1 core code that calls omap_w1_triplet (w1_triplet from w1_io.c)
doesn't care about error codes returned by omap_w1_triplet. Hence, I
will add a debug print and return 0x3 indicating to the w1 core to start
the search again.
>
>> + }
>> +
>> + hdq_data->hdq_irqstatus = 0;
>> + /* read id_bit */
>> + hdq_reg_merge(_hdq, OMAP_HDQ_CTRL_STATUS,
>> + ctrl | OMAP_HDQ_CTRL_STATUS_DIR, mask);
>> + wait_event_timeout(hdq_wait_queue,
>> + (hdq_data->hdq_irqstatus
>> + & OMAP_HDQ_INT_STATUS_RXCOMPLETE),
>> + OMAP_HDQ_TIMEOUT);
>
> It seems bad to ignore a timeout. Shouldn't the code clean up and
> report error when this occurs?
>
>
>> + id_bit = (hdq_reg_in(_hdq, OMAP_HDQ_RX_DATA) & 0x01);
>> +
>> + hdq_data->hdq_irqstatus = 0;
>> + /* read comp_bit */
>> + hdq_reg_merge(_hdq, OMAP_HDQ_CTRL_STATUS,
>> + ctrl | OMAP_HDQ_CTRL_STATUS_DIR, mask);
>> + wait_event_timeout(hdq_wait_queue,
>> + (hdq_data->hdq_irqstatus
>> + & OMAP_HDQ_INT_STATUS_RXCOMPLETE),
>> + OMAP_HDQ_TIMEOUT);
>
> Here too.
>
>> + comp_bit = (hdq_reg_in(_hdq, OMAP_HDQ_RX_DATA) & 0x01);
>> +
>> + if (id_bit && comp_bit) {
>> + ret = 0x03; /* error */
>> + goto rtn;
>> + }
>> + if (!id_bit && !comp_bit) {
>> + /* Both bits are valid, take the direction given */
>> + ret = bdir ? 0x04 : 0;
>> + } else {
>> + /* Only one bit is valid, take that direction */
>> + bdir = id_bit;
>> + ret = id_bit ? 0x05 : 0x02;
>> + }
>> +
>> + /* write bdir bit */
>> + hdq_reg_out(_hdq, OMAP_HDQ_TX_DATA, bdir);
>> + hdq_reg_merge(_hdq, OMAP_HDQ_CTRL_STATUS, ctrl, mask);
>> + wait_event_timeout(hdq_wait_queue,
>> + (hdq_data->hdq_irqstatus
>> + & OMAP_HDQ_INT_STATUS_TXCOMPLETE),
>> + OMAP_HDQ_TIMEOUT);
>
> And here.
I will add a dev_dbg() and return 0x3 indicating no devices responded in
all the above cases.
>
>> + hdq_reg_merge(_hdq, OMAP_HDQ_CTRL_STATUS, 0,
>> + OMAP_HDQ_CTRL_STATUS_SINGLE);
>> +
>> +rtn:
>> + mutex_unlock(&hdq_data->hdq_mutex);
>> + omap_hdq_put(_hdq);
>> + return ret;
>> +}
>>
>> ...
>>
Thanks & Regards
Vignesh
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