On Mon, Feb 22, 2016 at 04:41:22AM +0300, Sergei Ianovich wrote:
> DS1302 is half-duplex SPI device. The driver respects this fact now.
>
> Pin configurations should be implemented using SPI subsystem.
>
> Signed-off-by: Sergei Ianovich <[email protected]>
> CC: Alexandre Belloni <[email protected]>
> CC: Rob Herring <[email protected]>
> ---
> v5..v6
> * rewrite the driver as an SPI slave device
> * use "maxim" for vendor name per Kconfig
> * stop touching device RAM in device presence test
> * only return time from device if valid
> * use burst mode for reading/writing time
> * droppped charging control. I cannot test it, and it looks broken
>
> v4..v5
> * drop THIS_MODULE from struct platform driver
> * use "dallas" for vendor name per vendor-prefixes.txt
>
> v3..v4
> * move DTS bindings to a different patch
>
> v2..v3
> * use usleep_range instead of custom nsleep
> * number change (07/16 -> 09/21)
>
> v0..v2
> * use device tree
> * use devm helpers where possible
>
> .../devicetree/bindings/rtc/rtc-ds1302.txt | 46 +++
> drivers/rtc/Kconfig | 15 +-
> drivers/rtc/rtc-ds1302.c | 348
> ++++++++++-----------
> 3 files changed, 212 insertions(+), 197 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/rtc/rtc-ds1302.txt
>
> diff --git a/Documentation/devicetree/bindings/rtc/rtc-ds1302.txt
> b/Documentation/devicetree/bindings/rtc/rtc-ds1302.txt
> new file mode 100644
> index 0000000..b6c0973
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/rtc/rtc-ds1302.txt
> @@ -0,0 +1,46 @@
> +* Maxim/Dallas Semiconductor DS-1302 RTC
> +
> +Simple device which could be used to store date/time between reboots.
> +
> +The device uses the standard MicroWire half-duplex transfer timing.
> +Master output is set on low clock and sensed by the RTC on the rising
> +edge. Master input is set by the RTC on the trailing edge and is sensed
> +by the master on low clock.
> +
> +Required properties:
> +
> +- compatible : Should be "maxim,rtc-ds1302"
Just maxim,ds1032. RTC is implied by the part number and inline with
existing dallas,ds1307.
> +
> +Required SPI properties:
> +
> +- reg : Should be address of the device chip select within
> + the controller.
> +
> +- spi-max-frequency : DS-1302 has 500 kHz if powered at 2.2V,
> + and 2MHz if powered at 5V.
> +
> +- spi-3wire : The device has a shared signal IN/OUT line.
> +
> +- spi-lsb-first : DS-1302 requires least significant bit first
> + transfers.
> +
> +- spi-cs-high: DS-1302 has active high chip select line. This is
> + required unless inverted in hardware.
> +
> +Example:
> +
> +spi0@901c {
spi@...
> + #address-cells = <1>;
> + #size-cells = <0>;
> + compatible = "icpdas,spi-lp8841-rtc";
And this will need updating...
> + reg = <0x901c 0x1>;
> +
> + rtc@0 {
> + compatible = "maxim,rtc-ds1302";
> + reg = <0>;
> + spi-max-frequency = <500000>;
> + spi-3wire;
> + spi-lsb-first;
> + spi-cs-high;
> + };
> +};
