Hi Doug,
Last replied email HTML HEAD error, resend it.
? 2016/8/30 5:22, Douglas Anderson ??:
> Depending on a number of factors including:
> - Which exact Rockchip SoC we're working with
> - How deep we suspend
> - Which i2c port we're on
>
> We might lose the state of the i2c registers at suspend time.
> Specifically we've found that on rk3399 the i2c ports that are not in
> the PMU power domain lose their state with the current suspend depth
> configured by ARM Tursted Firmware.
>
> Note that there are very few actual i2c registers that aren't configured
> per transfer anyway so all we actually need to re-configure are the
> clock config registers. We'll just add a call to rk3x_i2c_adapt_div()
> at resume time and be done with it.
>
> NOTE: On rk3399 on ports whose power was lost, I put printouts in at
> resume time. I saw things like:
> before: con=0x00010300, div=0x00060006
> after: con=0x00010200, div=0x00180025
>
I do the suspend/resume stress test on my rk3399 & rk3288 board more
than 24 hours,
the patch works well, it looks nice to me.
Reviewed-by: David Wu <david.wu at rock-chips.com>
Tested-by: David Wu <david.wu at rock-chips.com>
> Signed-off-by: Douglas Anderson <dianders at chromium.org>
> ---
> Tested on chromeos-4.4 kernel with backports.
>
> drivers/i2c/busses/i2c-rk3x.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c
> index 3b87afe82f63..0df5ad6bfa31 100644
> --- a/drivers/i2c/busses/i2c-rk3x.c
> +++ b/drivers/i2c/busses/i2c-rk3x.c
> @@ -1111,6 +1111,15 @@ static int rk3x_i2c_xfer(struct i2c_adapter *adap,
> return ret < 0 ? ret : num;
> }
>
> +static __maybe_unused int rk3x_i2c_resume(struct device *dev)
> +{
> + struct rk3x_i2c *i2c = dev_get_drvdata(dev);
> +
> + rk3x_i2c_adapt_div(i2c, clk_get_rate(i2c->clk));
> +
> + return 0;
> +}
> +
> static u32 rk3x_i2c_func(struct i2c_adapter *adap)
> {
> return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
> @@ -1332,12 +1341,15 @@ static int rk3x_i2c_remove(struct platform_device *pdev)
> return 0;
> }
>
> +static const SIMPLE_DEV_PM_OPS(rk3x_i2c_pm_ops, NULL, rk3x_i2c_resume);
> +
> static struct platform_driver rk3x_i2c_driver = {
> .probe = rk3x_i2c_probe,
> .remove = rk3x_i2c_remove,
> .driver = {
> .name = "rk3x-i2c",
> .of_match_table = rk3x_i2c_match,
> + .pm = &rk3x_i2c_pm_ops,
> },
> };
>
>
