| 1 | |
| 2 | #include <linux/limits.h>
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| 3 | #include <linux/platform_device.h>
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| 4 | #include <linux/rtc.h>
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| 5 |
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| 6 | #include <linux/mfd/88pm886.h>
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| 7 |
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| 8 | |
| 9 | * Time is calculated as the sum of a 32-bit read-only advancing counter and a
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| 10 | * writeable constant offset stored in the chip's spare registers.
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| 11 |
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| 12 |
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| 13 | static int pm886_rtc_read_time(struct device *dev, struct rtc_time *tm)
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| 14 | {
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| 15 | struct regmap *regmap = dev_get_drvdata(dev);
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| 16 | u32 time;
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| 17 | u32 buf;
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| 18 | int ret;
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| 19 |
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| 20 | ret = regmap_bulk_read(regmap, PM886_REG_RTC_SPARE1, &buf, 4);
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| 21 | if (ret)
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| 22 | return ret;
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| 23 | time = buf;
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| 24 |
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| 25 | ret = regmap_bulk_read(regmap, PM886_REG_RTC_CNT1, &buf, 4);
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| 26 | if (ret)
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| 27 | return ret;
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| 28 | time += buf;
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| 29 |
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| 30 | rtc_time64_to_tm(time, tm);
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| 31 |
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| 32 | return 0;
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| 33 | }
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| 34 |
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| 35 | static int pm886_rtc_set_time(struct device *dev, struct rtc_time *tm)
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| 36 | {
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| 37 | struct regmap *regmap = dev_get_drvdata(dev);
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| 38 | u32 buf;
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| 39 | int ret;
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| 40 |
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| 41 | ret = regmap_bulk_read(regmap, PM886_REG_RTC_CNT1, &buf, 4);
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| 42 | if (ret)
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| 43 | return ret;
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| 44 |
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| 45 | buf = rtc_tm_to_time64(tm) - buf;
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| 46 |
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| 47 | return regmap_bulk_write(regmap, PM886_REG_RTC_SPARE1, &buf, 4);
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| 48 | }
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| 49 |
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| 50 | static const struct rtc_class_ops pm886_rtc_ops = {
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| 51 | .read_time = pm886_rtc_read_time,
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| 52 | .set_time = pm886_rtc_set_time,
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| 53 | };
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| 54 |
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| 55 | static int pm886_rtc_probe(struct platform_device *pdev)
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| 56 | {
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| 57 | struct pm886_chip *chip = dev_get_drvdata(pdev->dev.parent);
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| 58 | struct device *dev = &pdev->dev;
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| 59 | struct rtc_device *rtc;
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| 60 | int ret;
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| 61 |
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| 62 | platform_set_drvdata(pdev, chip->regmap);
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| 63 |
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| 64 | rtc = devm_rtc_allocate_device(dev);
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| 65 | if (IS_ERR(rtc))
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| 66 | return dev_err_probe(dev, PTR_ERR(rtc),
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| 67 | "Failed to allocate RTC device\n");
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| 68 |
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| 69 | rtc->ops = &pm886_rtc_ops;
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| 70 | rtc->range_max = U32_MAX;
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| 71 |
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| 72 | ret = devm_rtc_register_device(rtc);
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| 73 | if (ret)
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| 74 | return dev_err_probe(dev, ret, "Failed to register RTC device\n");
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| 75 |
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| 76 | return 0;
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| 77 | }
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| 78 |
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| 79 | static const struct platform_device_id pm886_rtc_id_table[] = {
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| 80 | { .name = "88pm886-rtc" },
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| 81 | { }
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| 82 | };
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| 83 | MODULE_DEVICE_TABLE(platform, pm886_rtc_id_table);
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| 84 |
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| 85 | static struct platform_driver pm886_rtc_driver = {
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| 86 | .driver = {
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| 87 | .name = "88pm886-rtc",
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| 88 | },
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| 89 | .probe = pm886_rtc_probe,
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| 90 | .id_table = pm886_rtc_id_table,
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| 91 | };
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| 92 | module_platform_driver(pm886_rtc_driver);
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| 93 |
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| 94 | MODULE_DESCRIPTION("Marvell 88PM886 RTC driver");
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| 95 | MODULE_AUTHOR("Karel Balej <[email protected]>");
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| 96 | MODULE_LICENSE("GPL");
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