On 12/12/2017 at 17:21:19 +0100, Romain Izard wrote:
> The controller used by a flexcom module is configured at boot, and left
> alone after this. In the suspend mode called "backup with self-refresh"
> available on SAMA5D2, the chip will resume with most of its registers
> reset. In this case, we need to restore the state of the flexcom driver
> on resume.
>
> Signed-off-by: Romain Izard <romain.izard....@gmail.com>
Seems good to me
Acked-by: Alexandre Belloni <alexandre.bell...@free-electrons.com>
> ---
> Changes in v5:
> * extract from the patch series, and send as a standalone patch
>
> Changes in v6:
> * Reword the patch title and description
> * Rename the internal structure to ddata
>
> drivers/mfd/atmel-flexcom.c | 63
> ++++++++++++++++++++++++++++++++++-----------
> 1 file changed, 48 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/mfd/atmel-flexcom.c b/drivers/mfd/atmel-flexcom.c
> index 064bde9cff5a..f684a93a3340 100644
> --- a/drivers/mfd/atmel-flexcom.c
> +++ b/drivers/mfd/atmel-flexcom.c
> @@ -39,34 +39,43 @@
> #define FLEX_MR_OPMODE(opmode) (((opmode) << FLEX_MR_OPMODE_OFFSET) &
> \
> FLEX_MR_OPMODE_MASK)
>
> +struct atmel_flexcom {
> + void __iomem *base;
> + u32 opmode;
> + struct clk *clk;
> +};
>
> static int atmel_flexcom_probe(struct platform_device *pdev)
> {
> struct device_node *np = pdev->dev.of_node;
> - struct clk *clk;
> struct resource *res;
> - void __iomem *base;
> - u32 opmode;
> + struct atmel_flexcom *ddata;
> int err;
>
> - err = of_property_read_u32(np, "atmel,flexcom-mode", &opmode);
> + ddata = devm_kzalloc(&pdev->dev, sizeof(*ddata), GFP_KERNEL);
> + if (!ddata)
> + return -ENOMEM;
> +
> + platform_set_drvdata(pdev, ddata);
> +
> + err = of_property_read_u32(np, "atmel,flexcom-mode", &ddata->opmode);
> if (err)
> return err;
>
> - if (opmode < ATMEL_FLEXCOM_MODE_USART ||
> - opmode > ATMEL_FLEXCOM_MODE_TWI)
> + if (ddata->opmode < ATMEL_FLEXCOM_MODE_USART ||
> + ddata->opmode > ATMEL_FLEXCOM_MODE_TWI)
> return -EINVAL;
>
> res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> - base = devm_ioremap_resource(&pdev->dev, res);
> - if (IS_ERR(base))
> - return PTR_ERR(base);
> + ddata->base = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(ddata->base))
> + return PTR_ERR(ddata->base);
>
> - clk = devm_clk_get(&pdev->dev, NULL);
> - if (IS_ERR(clk))
> - return PTR_ERR(clk);
> + ddata->clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(ddata->clk))
> + return PTR_ERR(ddata->clk);
>
> - err = clk_prepare_enable(clk);
> + err = clk_prepare_enable(ddata->clk);
> if (err)
> return err;
>
> @@ -76,9 +85,9 @@ static int atmel_flexcom_probe(struct platform_device *pdev)
> * inaccessible and are read as zero. Also the external I/O lines of the
> * Flexcom are muxed to reach the selected device.
> */
> - writel(FLEX_MR_OPMODE(opmode), base + FLEX_MR);
> + writel(FLEX_MR_OPMODE(ddata->opmode), ddata->base + FLEX_MR);
>
> - clk_disable_unprepare(clk);
> + clk_disable_unprepare(ddata->clk);
>
> return devm_of_platform_populate(&pdev->dev);
> }
> @@ -89,10 +98,34 @@ static const struct of_device_id atmel_flexcom_of_match[]
> = {
> };
> MODULE_DEVICE_TABLE(of, atmel_flexcom_of_match);
>
> +#ifdef CONFIG_PM_SLEEP
> +static int atmel_flexcom_resume(struct device *dev)
> +{
> + struct atmel_flexcom *ddata = dev_get_drvdata(dev);
> + int err;
> + u32 val;
> +
> + err = clk_prepare_enable(ddata->clk);
> + if (err)
> + return err;
> +
> + val = FLEX_MR_OPMODE(ddata->opmode),
> + writel(val, ddata->base + FLEX_MR);
> +
> + clk_disable_unprepare(ddata->clk);
> +
> + return 0;
> +}
> +#endif
> +
> +static SIMPLE_DEV_PM_OPS(atmel_flexcom_pm_ops, NULL,
> + atmel_flexcom_resume);
> +
> static struct platform_driver atmel_flexcom_driver = {
> .probe = atmel_flexcom_probe,
> .driver = {
> .name = "atmel_flexcom",
> + .pm = &atmel_flexcom_pm_ops,
> .of_match_table = atmel_flexcom_of_match,
> },
> };
> --
> 2.14.1
>
--
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
