linux/Documentation/devicetree/bindings/mmc/renesas,mmcif.txt
Kuninori Morimoto 89d49a706c mmc: sh_mmcif: calculate best clock with parent clock
MMCIF IP on R-Car series has parent clock which can be set several rate,
and it was not implemented on old SH-Mobile series (= SH-Mobile series
parent clock was fixed rate) R-Car series MMCIF can use more high speed
access if it setups parent clock. This patch adds parent clock setup
method. It will be used if DT has "max-frequency", and then, this driver
assumes it is booted on R-Car Gen2 or later SoC. Because SH-Mobile series
(which doesn't boot from DT) and R-Car series (which boots from DT) have
different divider.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Tested-by: Keita Kobayashi <keita.kobayashi.ym@renesas.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
[Ulf: Silence compiler warning]
2015-06-01 09:07:10 +02:00

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* Renesas Multi Media Card Interface (MMCIF) Controller
This file documents differences between the core properties in mmc.txt
and the properties used by the MMCIF device.
Required properties:
- compatible: must contain one of the following
- "renesas,mmcif-r8a7740" for the MMCIF found in r8a7740 SoCs
- "renesas,mmcif-r8a7790" for the MMCIF found in r8a7790 SoCs
- "renesas,mmcif-r8a7791" for the MMCIF found in r8a7791 SoCs
- "renesas,sh-mmcif" for the generic MMCIF
- clocks: reference to the functional clock
- dmas: reference to the DMA channels, one per channel name listed in the
dma-names property.
- dma-names: must contain "tx" for the transmit DMA channel and "rx" for the
receive DMA channel.
- max-frequency: Maximum operating clock frequency, driver uses default clock
frequency if it is not set.
Example: R8A7790 (R-Car H2) MMCIF0
mmcif0: mmc@ee200000 {
compatible = "renesas,mmcif-r8a7790", "renesas,sh-mmcif";
reg = <0 0xee200000 0 0x80>;
interrupts = <0 169 IRQ_TYPE_LEVEL_HIGH>;
clocks = <&mstp3_clks R8A7790_CLK_MMCIF0>;
dmas = <&dmac0 0xd1>, <&dmac0 0xd2>;
dma-names = "tx", "rx";
max-frequency = <97500000>;
};