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2022-12-12dt-bindings: rtc: m41t80: Convert text schema to YAML oneMarek Vasut
Convert the m41t80 text schema to YAML schema. Add "#clock-cells" requirement, which is required by clock-output-names. Signed-off-by: Marek Vasut <marex@denx.de> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Link: https://lore.kernel.org/r/20221211205124.23823-1-marex@denx.de Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
2021-05-25rtc: m41t80: add support for fixed clockSebastian Reichel
Congatec's QMX6 system on module (SoM) uses a m41t62 as RTC. The modules SQW clock output defaults to 32768 Hz. This behaviour is used to provide the i.MX6 CKIL clock. Once the RTC driver is probed, the clock is disabled and all i.MX6 functionality depending on the 32 KHz clock has undefined behaviour. For example when using the hardware watchdog the system will likely do arbitrary reboots. Referencing the m41t62 directly results in a deadlock. The kernel will see, that i.MX6 system clock needs the RTC clock and do probe deferral. But the i.MX6 I2C module never becomes usable without the i.MX6 CKIL clock and thus the RTC's clock will not be probed. So from the kernel's perspective this is a chicken-and-egg problem. Technically everything is fine by not touching anything, since the RTC clock correctly enables the clock on reset (i.e. on battery backup power loss) and also the bootloader enables it in case an something (e.g. an unpatched kernel) disabled this incorrectly. A workaround for this issue is describing the square wave pin as fixed-clock, which is registered early and basically how this pin is used on the i.MX6. Suggested-by: Saravana Kannan <saravanak@google.com> Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com> Reviewed-by: Saravana Kannan <saravanak@google.com> Reviewed-by: Rob Herring <robh@kernel.org> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210428222953.235280-2-sebastian.reichel@collabora.com
2018-07-25dt-bindings: remove 'interrupt-parent' from bindingsRob Herring
'interrupt-parent' is often documented as part of define bindings, but it is really outside the scope of a device binding. It's never required in a given node as it is often inherited from a parent node. Or it can be implicit if a parent node is an 'interrupt-controller' node. So remove it from all the binding files. Cc: Mark Rutland <mark.rutland@arm.com> Cc: devicetree@vger.kernel.org Signed-off-by: Rob Herring <robh@kernel.org>
2017-10-05dt-bindings: rtc: Add bindings for m41t80 and compatiblesAlexandre Belloni
The ST M41T80 family of RTC are not trivial devices, document them. Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Signed-off-by: Rob Herring <robh@kernel.org>