[alsa-devel] [PATCH v4 05/13] soundwire: Add helpers for ports operations

[Pierre-Louis Bossart]

> +static int sdw_enable_disable_slave_ports(struct sdw_bus *bus,
> +				struct sdw_slave_runtime *s_rt,
> +				struct sdw_port_runtime *p_rt, bool en)
> +{
> +	struct sdw_transport_params *t_params = &p_rt->transport_params;
> +	u32 addr;
> +	int ret;
> +
> +	if (bus->params.next_bank)
> +		addr = SDW_DPN_CHANNELEN_B1(p_rt->num);
> +	else
> +		addr = SDW_DPN_CHANNELEN_B0(p_rt->num);
> +
> +	/*
> +	 * Since bus doesn't support sharing a port across two streams,
> +	 * it is safe to reset this register
> +	 */
> +	if (en)
> +		ret = sdw_update(s_rt->slave, addr, 0xFF, p_rt->ch_mask);
> +	else
> +		ret = sdw_update(s_rt->slave, addr, 0xFF, 0x0);
> +
> +	if (ret < 0)
> +		dev_err(&s_rt->slave->dev,
> +			"Slave chn_en reg write failed:%d port:%d",
> +			ret, t_params->port_num);
> +
> +	return ret;
> +}

Add a clarification that this routine only sets the enable/disable bits 
in the relevant bank, the actual enable/disable is done with a bank switch.