I2C_IMSCR
writel(0, priv->virtbase + I2C_IMSCR);
writel(readl(priv->virtbase + I2C_IMSCR) | irq_mask,
priv->virtbase + I2C_IMSCR);
writel(readl(priv->virtbase + I2C_IMSCR) | irq_mask,
priv->virtbase + I2C_IMSCR);
writel(readl(priv->virtbase + I2C_IMSCR) & ~irq,
priv->virtbase + I2C_IMSCR);