On 14/04/2017 at 10:22:43 +0200, Quentin Schulz wrote:
> This adds deepest (Backup+Self-Refresh) PM support to the ATMEL SAMA5D2
> SoC's SPI controller.
>
> When resuming from deepest state, it is required to restore MR register
> as the registers are lost since VDD core has been shut down when
> entering deepest state on the SAMA5D2.
>
> Signed-off-by: Quentin Schulz <quentin.sch...@free-electrons.com>
Acked-by: Alexandre Belloni <alexandre.bell...@free-electrons.com>
> ---
>
> v2:
> - fix commit log explanation on why restoring the registers is required
> after resuming from deepest state,
>
> drivers/spi/spi-atmel.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
> index 247d920..1eb83c9 100644
> --- a/drivers/spi/spi-atmel.c
> +++ b/drivers/spi/spi-atmel.c
> @@ -1702,8 +1702,17 @@ static int atmel_spi_suspend(struct device *dev)
> static int atmel_spi_resume(struct device *dev)
> {
> struct spi_master *master = dev_get_drvdata(dev);
> + struct atmel_spi *as = spi_master_get_devdata(master);
> int ret;
>
> + ret = clk_prepare_enable(as->clk);
> + if (ret)
> + return ret;
> +
> + atmel_spi_init(as);
> +
> + clk_disable_unprepare(as->clk);
> +
> if (!pm_runtime_suspended(dev)) {
> ret = atmel_spi_runtime_resume(dev);
> if (ret)
> --
> 2.9.3
>
--
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
