Re: [PATCH V3 1/4] i2c: tegra: make sure register writes completes

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Wednesday 13 June 2012 09:25 PM, Stephen Warren wrote:
On 06/13/2012 04:12 AM, Laxman Dewangan wrote:
@@ -165,6 +165,10 @@ static void i2c_writel(struct tegra_i2c_dev *i2c_dev, u32 val,
  	unsigned long reg)
  {
  	writel(val, i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg));
+
+	/* Read back register to make sure that register writes completed */
+	if (reg != I2C_TX_FIFO)
+		readl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg));
I guess that's fine, but it sure does seem rather heavy-weight. Don't
you only need to do the readback if you just wrote to the IRQ status or
mask registers, rather than if you wrote to /any/ register other than
the FIFO?

That's what my second patch but based on your earlier review comment, I did for every register.

I think it will not matter much as we dont write all register with every transaction, only during initialization. Then for each transfer we write manly on Tx fifo and interrupt mask/status register and hence not too much overweight.

--
To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [Linux GPIO]     [Linux SPI]     [Linux Hardward Monitoring]     [LM Sensors]     [Linux USB Devel]     [Linux Media]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux