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author | Romain Izard <romain.izard.pro@gmail.com> | 2017-12-12 17:21:19 +0100 |
---|---|---|
committer | Lee Jones <lee.jones@linaro.org> | 2018-01-08 12:03:35 +0100 |
commit | 7fdec11015c374a6f0b29ceccf35f559c2208042 (patch) | |
tree | 5807f61ff756b297983767f7b92b11e8c5429709 /drivers/mfd/atmel-flexcom.c | |
parent | mfd: Remove duplicate includes (diff) | |
download | linux-7fdec11015c374a6f0b29ceccf35f559c2208042.tar.xz linux-7fdec11015c374a6f0b29ceccf35f559c2208042.zip |
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 <romain.izard.pro@gmail.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Tested-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Diffstat (limited to '')
-rw-r--r-- | drivers/mfd/atmel-flexcom.c | 63 |
1 files 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, }, }; |