Re: [PATCH v3 3/3] i2c: qcom-geni: Add bus recovery support for GPI DMA mode

[Mukesh Savaliya <mukesh.savaliya@oss.qualcomm.com>]

On 10/27/2026 10:43 AM, Aniket Randive wrote:
[...]

> +static int geni_i2c_gpi_bus_cmd(struct geni_i2c_dev *gi2c, enum i2c_op cmd)
> +{
> +	const struct geni_i2c_clk_fld *itr = gi2c->clk_fld;
> +	struct dma_async_tx_descriptor *desc;
> +	struct gpi_i2c_config peripheral = {};
> +	struct dma_slave_config config = {};
> +	unsigned long time_left;
> +	unsigned long flags;
> +	dma_cookie_t cookie;
> +	int ret;
> +
> +	config.peripheral_config = &peripheral;
> +	config.peripheral_size = sizeof(peripheral);
> +
> +	peripheral.set_config  = 1;
> +	peripheral.pack_enable = I2C_PACK_TX | I2C_PACK_RX;
> +	peripheral.cycle_count = itr->t_cycle_cnt;
> +	peripheral.high_count  = itr->t_high_cnt;
> +	peripheral.low_count   = itr->t_low_cnt;
> +	peripheral.clk_div     = itr->clk_div;
> +	peripheral.op          = cmd;
> +
> +	ret = dmaengine_slave_config(gi2c->tx_c, &config);
> +	if (ret) {
> +		dev_err(gi2c->se.dev, "dma config error %d for bus cmd %u\n", ret, cmd);
> +		return ret;
> +	}
> +
> +	desc = dmaengine_prep_slave_single(gi2c->tx_c, 0, 0, DMA_MEM_TO_DEV,
> +					   DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
> +	if (!desc)
> +		return -EIO;
> +
> +	desc->callback_result = i2c_gpi_cb_result;
> +	desc->callback_param = gi2c;
> +
> +	cookie = dmaengine_submit(desc);
> +	if (dma_submit_error(cookie))
> +		return -EIO;

Rather capture ret and return it if it's an error ?

> +
> +	/*
> +	 * cur and err are shared with geni_i2c_irq() and the GPI callback
> +	 * i2c_gpi_cb_result(); both write err (the IRQ handler under
> +	 * gi2c->lock). Reset them under the lock before issuing the transfer.
> +	 */
> +	spin_lock_irqsave(&gi2c->lock, flags);
> +	gi2c->cur = NULL;
> +	gi2c->err = 0;
> +	spin_unlock_irqrestore(&gi2c->lock, flags);
> +	reinit_completion(&gi2c->done);
Safe to init before dmaengine_submit().> + 
dma_async_issue_pending(gi2c->tx_c);
> +
> +	time_left = wait_for_completion_timeout(&gi2c->done, gi2c->adap.timeout);
> +	if (!time_left) {
> +		dev_err(gi2c->se.dev, "timeout waiting for GPI bus cmd %u\n", cmd);
> +		ret = dmaengine_terminate_sync(gi2c->tx_c);
> +		if (ret)
> +			dev_err(gi2c->se.dev, "DMA termination failed for bus cmd %u: %d\n",
> +				cmd, ret);
> +		return -ETIMEDOUT;
> +	}
> +
> +	return gi2c->err;
> +}
> +[...]