Re: [RFC PATCH v4 04/14] i2c: tegra: Fix runtime resume to re-init VI I2C

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On 7/26/20 4:53 PM, Dmitry Osipenko wrote:
24.07.2020 02:51, Sowjanya Komatineni пишет:
VI I2C is on host1x bus and is part of VE power domain.

During suspend/resume VE power domain goes through power off/on.

So, controller reset followed by i2c re-initialization is required
after the domain power up.

This patch fixes it.

Signed-off-by: Sowjanya Komatineni <skomatineni@xxxxxxxxxx>
---
  drivers/i2c/busses/i2c-tegra.c | 16 ++++++++++++++++
  1 file changed, 16 insertions(+)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 7b93c45..1bf3666 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -293,6 +293,8 @@ struct tegra_i2c_dev {
  	bool is_curr_atomic_xfer;
  };
+static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev, bool clk_reinit);
+
  static void dvc_writel(struct tegra_i2c_dev *i2c_dev, u32 val,
  		       unsigned long reg)
  {
@@ -675,8 +677,22 @@ static int __maybe_unused tegra_i2c_runtime_resume(struct device *dev)
  		goto disable_slow_clk;
  	}
+ /*
+	 * VI I2C device is attached to VE power domain which goes through
+	 * power ON/OFF during PM runtime resume/suspend. So, controller
+	 * should go through reset and need to re-initialize after power
+	 * domain ON.
+	 */
+	if (i2c_dev->is_vi) {
+		ret = tegra_i2c_init(i2c_dev, true);
+		if (ret)
+			goto disable_div_clk;
+	}
+
  	return 0;
+disable_div_clk:
+	clk_disable(i2c_dev->div_clk);
  disable_slow_clk:
  	clk_disable(i2c_dev->slow_clk);
  disable_fast_clk:

This look okay, but isn't RPM usage a bit too expensive for VI? Maybe
RPM autodelay needs to be set for the I2C driver?

Reviewed-by: Dmitry Osipenko <digetx@xxxxxxxxx>

Thanks Dmitry. Will look into and have separate patch for VI I2C RPM auto-delay out of this series sometime next week.

Regards

Sowjanya





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