From 7fdec11015c374a6f0b29ceccf35f559c2208042 Mon Sep 17 00:00:00 2001 From: Romain Izard Date: Tue, 12 Dec 2017 17:21:19 +0100 Subject: atmel_flexcom: Support resuming after a chip reset 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 Acked-by: Alexandre Belloni Acked-by: Nicolas Ferre Tested-by: Nicolas Ferre Signed-off-by: Lee Jones --- 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, }, }; -- cgit