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?
> + }
> +
> + 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.
> + 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;
> +}
>
> ...
>
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