forked from Minki/linux
c373eb489b
Provide the option to configure these speed modes per host, for those host driver's that can't distinguish this in runtime. Specially, if host can support HS400, it means that host can also support HS200. Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Chris Ball <chris@printf.net>
79 lines
3.6 KiB
Plaintext
79 lines
3.6 KiB
Plaintext
These properties are common to multiple MMC host controllers. Any host
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that requires the respective functionality should implement them using
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these definitions.
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Interpreted by the OF core:
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- reg: Registers location and length.
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- interrupts: Interrupts used by the MMC controller.
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Card detection:
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If no property below is supplied, host native card detect is used.
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Only one of the properties in this section should be supplied:
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- broken-cd: There is no card detection available; polling must be used.
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- cd-gpios: Specify GPIOs for card detection, see gpio binding
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- non-removable: non-removable slot (like eMMC); assume always present.
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Optional properties:
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- bus-width: Number of data lines, can be <1>, <4>, or <8>. The default
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will be <1> if the property is absent.
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- wp-gpios: Specify GPIOs for write protection, see gpio binding
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- cd-inverted: when present, polarity on the CD line is inverted. See the note
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below for the case, when a GPIO is used for the CD line
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- wp-inverted: when present, polarity on the WP line is inverted. See the note
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below for the case, when a GPIO is used for the WP line
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- max-frequency: maximum operating clock frequency
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- no-1-8-v: when present, denotes that 1.8v card voltage is not supported on
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this system, even if the controller claims it is.
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- cap-sd-highspeed: SD high-speed timing is supported
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- cap-mmc-highspeed: MMC high-speed timing is supported
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- sd-uhs-sdr12: SD UHS SDR12 speed is supported
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- sd-uhs-sdr25: SD UHS SDR25 speed is supported
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- sd-uhs-sdr50: SD UHS SDR50 speed is supported
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- sd-uhs-sdr104: SD UHS SDR104 speed is supported
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- sd-uhs-ddr50: SD UHS DDR50 speed is supported
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- cap-power-off-card: powering off the card is safe
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- cap-sdio-irq: enable SDIO IRQ signalling on this interface
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- full-pwr-cycle: full power cycle of the card is supported
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- mmc-highspeed-ddr-1_8v: eMMC high-speed DDR mode(1.8V I/O) is supported
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- mmc-highspeed-ddr-1_2v: eMMC high-speed DDR mode(1.2V I/O) is supported
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- mmc-hs200-1_8v: eMMC HS200 mode(1.8V I/O) is supported
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- mmc-hs200-1_2v: eMMC HS200 mode(1.2V I/O) is supported
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- mmc-hs400-1_8v: eMMC HS400 mode(1.8V I/O) is supported
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- mmc-hs400-1_2v: eMMC HS400 mode(1.2V I/O) is supported
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*NOTE* on CD and WP polarity. To use common for all SD/MMC host controllers line
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polarity properties, we have to fix the meaning of the "normal" and "inverted"
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line levels. We choose to follow the SDHCI standard, which specifies both those
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lines as "active low." Therefore, using the "cd-inverted" property means, that
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the CD line is active high, i.e. it is high, when a card is inserted. Similar
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logic applies to the "wp-inverted" property.
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CD and WP lines can be implemented on the hardware in one of two ways: as GPIOs,
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specified in cd-gpios and wp-gpios properties, or as dedicated pins. Polarity of
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dedicated pins can be specified, using *-inverted properties. GPIO polarity can
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also be specified using the OF_GPIO_ACTIVE_LOW flag. This creates an ambiguity
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in the latter case. We choose to use the XOR logic for GPIO CD and WP lines.
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This means, the two properties are "superimposed," for example leaving the
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OF_GPIO_ACTIVE_LOW flag clear and specifying the respective *-inverted
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property results in a double-inversion and actually means the "normal" line
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polarity is in effect.
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Optional SDIO properties:
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- keep-power-in-suspend: Preserves card power during a suspend/resume cycle
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- enable-sdio-wakeup: Enables wake up of host system on SDIO IRQ assertion
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Example:
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sdhci@ab000000 {
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compatible = "sdhci";
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reg = <0xab000000 0x200>;
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interrupts = <23>;
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bus-width = <4>;
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cd-gpios = <&gpio 69 0>;
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cd-inverted;
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wp-gpios = <&gpio 70 0>;
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max-frequency = <50000000>;
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keep-power-in-suspend;
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enable-sdio-wakeup;
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}
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