netdev - Re: [PATCH net-next 4/8] mlxsw: i2c: Add support for system interrupt handling

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Date:   Mon, 22 Aug 2022 03:48:39 +0200
From:   Andrew Lunn <andrew@...n.ch>
To:     Petr Machata <petrm@...dia.com>
Cc:     "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>, netdev@...r.kernel.org,
        Vadim Pasternak <vadimp@...dia.com>,
        Ido Schimmel <idosch@...dia.com>, mlxsw@...dia.com,
        Jiri Pirko <jiri@...dia.com>
Subject: Re: [PATCH net-next 4/8] mlxsw: i2c: Add support for system
 interrupt handling

> +static void mlxsw_i2c_work_handler(struct work_struct *work)
> +{
> +	struct mlxsw_i2c *mlxsw_i2c;
> +
> +	mlxsw_i2c = container_of(work, struct mlxsw_i2c, irq_work);
> +	mlxsw_core_irq_event_handlers_call(mlxsw_i2c->core);
> +}
> +
> +static irqreturn_t mlxsw_i2c_irq_handler(int irq, void *dev)
> +{
> +	struct mlxsw_i2c *mlxsw_i2c = dev;
> +
> +	mlxsw_core_schedule_work(&mlxsw_i2c->irq_work);
> +
> +	/* Interrupt handler shares IRQ line with 'main' interrupt handler.
> +	 * Return here IRQ_NONE, while main handler will return IRQ_HANDLED.
> +	 */
> +	return IRQ_NONE;
> +}
> +
> +static int mlxsw_i2c_irq_init(struct mlxsw_i2c *mlxsw_i2c, u8 addr)
> +{
> +	int err;
> +
> +	/* Initialize interrupt handler if system hotplug driver is reachable,
> +	 * otherwise interrupt line is not enabled and interrupts will not be
> +	 * raised to CPU. Also request_irq() call will be not valid.
> +	 */
> +	if (!IS_REACHABLE(CONFIG_MLXREG_HOTPLUG))
> +		return 0;
> +
> +	/* Set default interrupt line. */
> +	if (mlxsw_i2c->pdata && mlxsw_i2c->pdata->irq)
> +		mlxsw_i2c->irq = mlxsw_i2c->pdata->irq;
> +	else if (addr == MLXSW_FAST_I2C_SLAVE)
> +		mlxsw_i2c->irq = MLXSW_I2C_DEFAULT_IRQ;
> +
> +	if (!mlxsw_i2c->irq)
> +		return 0;
> +
> +	INIT_WORK(&mlxsw_i2c->irq_work, mlxsw_i2c_work_handler);
> +	err = request_irq(mlxsw_i2c->irq, mlxsw_i2c_irq_handler,
> +			  IRQF_TRIGGER_FALLING | IRQF_SHARED, "mlxsw-i2c",
> +			  mlxsw_i2c);

I think you can make this simpler by using a request_threaded_irq()

  Andrew