kernel/linux.git/drivers/rtc/rtc-s3c.c, branch v6.18.21

rtc: s3c: Drop support for S3C2410

2025-09-16T15:38:20+00:00

Samsung S3C24xx family of SoCs was removed the Linux kernel in the commit 61b7f8920b17 ("ARM: s3c: remove all s3c24xx support"), in January 2023. There are no in-kernel users of remaining S3C24xx compatibles. Signed-off-by: Krzysztof Kozlowski Link: https://lore.kernel.org/r/20250830130024.142815-5-krzysztof.kozlowski@linaro.org Signed-off-by: Alexandre Belloni

rtc: s3c: Put 'const' just after 'static' keyword for data

2025-07-22T22:45:21+00:00

Convention is to define static data as 'static const ...', not 'static ... const' because of readability, even if the code is functionally equal. Signed-off-by: Krzysztof Kozlowski Link: https://lore.kernel.org/r/20250707092200.48862-2-krzysztof.kozlowski@linaro.org Signed-off-by: Alexandre Belloni

rtc: s3c: drop unused module alias

2025-05-24T21:58:24+00:00

The driver only support OF probe so drop the unused platform module alias. Fixes: ae05c95074e0 ("rtc: s3c: add s3c_rtc_data structure to use variant data instead of s3c_cpu_type") Signed-off-by: Johan Hovold Fixes: 0d297df03890 ("ARM: s3c: simplify platform code") Reviewed-by: Krzysztof Kozlowski Link: https://lore.kernel.org/r/20250423130318.31244-7-johan+linaro@kernel.org Signed-off-by: Alexandre Belloni

rtc: use boolean values with device_init_wakeup()

2025-01-09T17:29:24+00:00

device_init_wakeup() second argument is a bool type. Use proper boolean values when calling it to match the type and to produce unambiguous code which is easier to understand. Signed-off-by: Wolfram Sang Reviewed-by: Charles Keepax Reviewed-by: Andre Przywara Link: https://lore.kernel.org/r/20241217071331.3607-2-wsa+renesas@sang-engineering.com Signed-off-by: Alexandre Belloni

rtc: Switch back to struct platform_driver::remove()

2024-11-10T21:58:28+00:00

After commit 0edb555a65d1 ("platform: Make platform_driver::remove() return void") .remove() is (again) the right callback to implement for platform drivers. Convert all platform drivers below drivers/rtc to use .remove(), with the eventual goal to drop struct platform_driver::remove_new(). As .remove() and .remove_new() have the same prototypes, conversion is done by just changing the structure member name in the driver initializer. Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/20241007205803.444994-6-u.kleine-koenig@baylibre.com Signed-off-by: Alexandre Belloni

rtc: Explicitly include correct DT includes

2023-07-27T21:31:29+00:00

The DT of_device.h and of_platform.h date back to the separate of_platform_bus_type before it as merged into the regular platform bus. As part of that merge prepping Arm DT support 13 years ago, they "temporarily" include each other. They also include platform_device.h and of.h. As a result, there's a pretty much random mix of those include files used throughout the tree. In order to detangle these headers and replace the implicit includes with struct declarations, users need to explicitly include the correct includes. Signed-off-by: Rob Herring Link: https://lore.kernel.org/r/20230724205456.767430-1-robh@kernel.org Signed-off-by: Alexandre Belloni

rtc: s3c: Convert to platform remove callback returning void

2023-03-17T22:03:18+00:00

The .remove() callback for a platform driver returns an int which makes many driver authors wrongly assume it's possible to do error handling by returning an error code. However the value returned is (mostly) ignored and this typically results in resource leaks. To improve here there is a quest to make the remove callback return void. In the first step of this quest all drivers are converted to .remove_new() which already returns void. Trivially convert this driver from always returning zero in the remove callback to the void returning variant. Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/20230304133028.2135435-30-u.kleine-koenig@pengutronix.de Signed-off-by: Alexandre Belloni

rtc: s3c: Switch to use dev_err_probe() helper

2022-11-15T20:01:51+00:00

In the probe path, dev_err() can be replace with dev_err_probe() which will check if error code is -EPROBE_DEFER and prints the error name. Signed-off-by: Yang Yingliang Link: https://lore.kernel.org/r/20220919083812.755082-1-yangyingliang@huawei.com Signed-off-by: Alexandre Belloni

rtc: s3c: Add time range

2021-10-23T21:57:23+00:00

This RTC driver starts counting from 2000 to avoid Y2K problem. Also it only supports 100 years range for all RTCs. Provide that info to RTC framework. Also remove check for 100 years range in s3c_rtc_settime(), as RTC core won't pass any invalid values to the driver, now that correct range is set. Here is the rationale on 100 years range limitation. Info on different Samsung RTCs (credit goes to Krzysztof Kozlowski): - All S3C chips have only 8-bit wide year register (can store 100 years range in BCD format) - S5Pv210 and Exynos chips have 12-bit year register (can store 1000 years range in BCD format) But in reality we usually can't make use of those 12 bits either: - RTCs might think that both 2000 and 2100 years are leap years. So when the YEAR register is 0, RTC goes from 28 Feb to 29 Feb, and when the YEAR register is 100, RTC also goes from 28 Feb to 29 Feb. This is of course incorrect: RTC breaks leap year criteria, which breaks the time contiguity, which leads to inability to use the RTC after year of 2099. It was found for example on Exynos850 SoC. - Despite having 12 bits for holding the year value, RTC might overflow the year value internally much earlier. For example, on Exynos850 the RTC overflows when YEAR=159, making the next YEAR=0. This way RTC actually has range of 160 years, not 1000 as one may think. All that said, there is no sense in trying to increase the time range for more than 100 years on RTCs that seem capable of that. It also doesn't have too much practical value -- current hardware will be probably obsolete by 2100. Tested manually on Exynos850 RTC: $ date -s "1999-12-31 23:59:50" $ hwclock -w -f /dev/rtc0 $ date -s "2100-01-01 00:00:00" $ hwclock -w -f /dev/rtc0 $ date -s "2000-01-01 00:00:00" $ hwclock -w -f /dev/rtc0 $ hwclock -r -f /dev/rtc0 $ date -s "2099-12-31 23:59:50" $ hwclock -w -f /dev/rtc0 $ hwclock -r -f /dev/rtc0 Signed-off-by: Sam Protsenko Reviewed-by: Krzysztof Kozlowski Signed-off-by: Alexandre Belloni Link: https://lore.kernel.org/r/20211021202256.28517-4-semen.protsenko@linaro.org

rtc: s3c: Extract read/write IO into separate functions

2021-10-23T21:57:23+00:00

Create dedicated functions for I/O operations and BCD conversion. It can be useful to separate those from representation conversion and other stuff found in RTC callbacks. This patch does not introduce any functional changes, it's merely refactoring change. Signed-off-by: Sam Protsenko Reviewed-by: Krzysztof Kozlowski Signed-off-by: Alexandre Belloni Link: https://lore.kernel.org/r/20211021202256.28517-3-semen.protsenko@linaro.org