PS2_REG_FSTS
fifo_status = readl(drvdata->reg_base + PS2_REG_FSTS);
writel(rval, drvdata->reg_base + PS2_REG_FSTS);
writel(fifo_status, drvdata->reg_base + PS2_REG_FSTS);
if (readl(drvdata->reg_base + PS2_REG_FSTS) & PS2_FSTS_TXRDY) {