[PATCH v1 09/10] atmel_flexcom: Support backup mode

Romain Izard
2017-09-08T15:36:40Z

The controller used by a flexcom module is configured at boot, and left
alone after this. As the configuration will be lost after backup mode,
restore the state of the flexcom driver on resume.

Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>
---
drivers/mfd/atmel-flexcom.c | 65 ++++++++++++++++++++++++++++++++++-----------
1 file changed, 50 insertions(+), 15 deletions(-)

diff --git a/drivers/mfd/atmel-flexcom.c b/drivers/mfd/atmel-flexcom.c
index 064bde9cff5a..ef1235c4a179 100644
--- a/drivers/mfd/atmel-flexcom.c
+++ b/drivers/mfd/atmel-flexcom.c
@@ -39,34 +39,44 @@
#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 *afc;
int err;
+ u32 val;
+
+ afc = devm_kzalloc(&pdev->dev, sizeof(*afc), GFP_KERNEL);
+ if (!afc)
+ return -ENOMEM;

- err = of_property_read_u32(np, "atmel,flexcom-mode", &opmode);
+ platform_set_drvdata(pdev, afc);
+
+ err = of_property_read_u32(np, "atmel,flexcom-mode", &afc->opmode);
if (err)
return err;

- if (opmode < ATMEL_FLEXCOM_MODE_USART ||
- opmode > ATMEL_FLEXCOM_MODE_TWI)
+ if (afc->opmode < ATMEL_FLEXCOM_MODE_USART ||
+ afc->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);
+ afc->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(afc->base))
+ return PTR_ERR(afc->base);

- clk = devm_clk_get(&pdev->dev, NULL);
- if (IS_ERR(clk))
- return PTR_ERR(clk);
+ afc->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(afc->clk))
+ return PTR_ERR(afc->clk);

- err = clk_prepare_enable(clk);
+ err = clk_prepare_enable(afc->clk);
if (err)
return err;

@@ -76,9 +86,10 @@ 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);
+ val = FLEX_MR_OPMODE(afc->opmode);
+ writel(val, afc->base + FLEX_MR);

- clk_disable_unprepare(clk);
+ clk_disable_unprepare(afc->clk);

return devm_of_platform_populate(&pdev->dev);
}
@@ -89,10 +100,34 @@ 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 *afc = dev_get_drvdata(dev);
+ int err;
+ u32 val;
+
+ err = clk_prepare_enable(afc->clk);
+ if (err)
+ return err;
+
+ val = FLEX_MR_OPMODE(afc->opmode),
+ writel(val, afc->base + FLEX_MR);
+
+ clk_disable_unprepare(afc->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,
},
};
--
2.11.0