int sdw_bus_prep_clk_stop()

in bus.c [933:1022]

• 55 lines of code
• 17 McCabe index (conditional complexity)

int sdw_bus_prep_clk_stop(struct sdw_bus *bus)
{
	bool simple_clk_stop = true;
	struct sdw_slave *slave;
	bool is_slave = false;
	int ret = 0;

	/*
	 * In order to save on transition time, prepare
	 * each Slave and then wait for all Slave(s) to be
	 * prepared for clock stop.
	 * If one of the Slave devices has lost sync and
	 * replies with Command Ignored/-ENODATA, we continue
	 * the loop
	 */
	list_for_each_entry(slave, &bus->slaves, node) {
		if (!slave->dev_num)
			continue;

		if (slave->status != SDW_SLAVE_ATTACHED &&
		    slave->status != SDW_SLAVE_ALERT)
			continue;

		/* Identify if Slave(s) are available on Bus */
		is_slave = true;

		ret = sdw_slave_clk_stop_callback(slave,
						  SDW_CLK_STOP_MODE0,
						  SDW_CLK_PRE_PREPARE);
		if (ret < 0 && ret != -ENODATA) {
			dev_err(&slave->dev, "clock stop pre-prepare cb failed:%d\n", ret);
			return ret;
		}

		/* Only prepare a Slave device if needed */
		if (!slave->prop.simple_clk_stop_capable) {
			simple_clk_stop = false;

			ret = sdw_slave_clk_stop_prepare(slave,
							 SDW_CLK_STOP_MODE0,
							 true);
			if (ret < 0 && ret != -ENODATA) {
				dev_err(&slave->dev, "clock stop prepare failed:%d\n", ret);
				return ret;
			}
		}
	}

	/* Skip remaining clock stop preparation if no Slave is attached */
	if (!is_slave)
		return 0;

	/*
	 * Don't wait for all Slaves to be ready if they follow the simple
	 * state machine
	 */
	if (!simple_clk_stop) {
		ret = sdw_bus_wait_for_clk_prep_deprep(bus,
						       SDW_BROADCAST_DEV_NUM);
		/*
		 * if there are no Slave devices present and the reply is
		 * Command_Ignored/-ENODATA, we don't need to continue with the
		 * flow and can just return here. The error code is not modified
		 * and its handling left as an exercise for the caller.
		 */
		if (ret < 0)
			return ret;
	}

	/* Inform slaves that prep is done */
	list_for_each_entry(slave, &bus->slaves, node) {
		if (!slave->dev_num)
			continue;

		if (slave->status != SDW_SLAVE_ATTACHED &&
		    slave->status != SDW_SLAVE_ALERT)
			continue;

		ret = sdw_slave_clk_stop_callback(slave,
						  SDW_CLK_STOP_MODE0,
						  SDW_CLK_POST_PREPARE);

		if (ret < 0 && ret != -ENODATA) {
			dev_err(&slave->dev, "clock stop post-prepare cb failed:%d\n", ret);
			return ret;
		}
	}

	return 0;
}