* TI Highspeed MMC host controller for OMAP and 66AK2G family. The Highspeed MMC Host Controller on TI OMAP and 66AK2G family provides an interface for MMC, SD, and SDIO types of memory cards. This file documents differences between the core properties described by mmc.txt and the properties used by the omap_hsmmc driver. Required properties: -------------------- - compatible: Should be "ti,omap2-hsmmc", for OMAP2 controllers Should be "ti,omap3-hsmmc", for OMAP3 controllers Should be "ti,omap3-pre-es3-hsmmc" for OMAP3 controllers pre ES3.0 Should be "ti,omap4-hsmmc", for OMAP4 controllers Should be "ti,am33xx-hsmmc", for AM335x controllers Should be "ti,k2g-hsmmc", "ti,omap4-hsmmc" for 66AK2G controllers. SoC specific required properties: --------------------------------- The following are mandatory properties for OMAPs, AM33xx and AM43xx SoCs only: - ti,hwmods: Must be "mmc<n>", n is controller instance starting 1. The following are mandatory properties for 66AK2G SoCs only: - power-domains:Should contain a phandle to a PM domain provider node and an args specifier containing the MMC device id value. This property is as per the binding, Documentation/devicetree/bindings/soc/ti/sci-pm-domain.yaml - clocks: Must contain an entry for each entry in clock-names. Should be defined as per the he appropriate clock bindings consumer usage in Documentation/devicetree/bindings/clock/ti,sci-clk.yaml - clock-names: Shall be "fck" for the functional clock, and "mmchsdb_fck" for the debounce clock. Optional properties: -------------------- - ti,dual-volt: boolean, supports dual voltage cards - <supply-name>-supply: phandle to the regulator device tree node "supply-name" examples are "vmmc", "vmmc_aux"(deprecated)/"vqmmc" etc - ti,non-removable: non-removable slot (like eMMC) - ti,needs-special-reset: Requires a special softreset sequence - ti,needs-special-hs-handling: HSMMC IP needs special setting for handling High Speed - dmas: List of DMA specifiers with the controller specific format as described in the generic DMA client binding. A tx and rx specifier is required. - dma-names: List of DMA request names. These strings correspond 1:1 with the DMA specifiers listed in dmas. The string naming is to be "rx" and "tx" for RX and TX DMA requests, respectively. Examples: [hwmod populated DMA resources] mmc1: mmc@4809c000 { compatible = "ti,omap4-hsmmc"; reg = <0x4809c000 0x400>; ti,hwmods = "mmc1"; ti,dual-volt; bus-width = <4>; vmmc-supply = <&vmmc>; /* phandle to regulator node */ ti,non-removable; }; [generic DMA request binding] mmc1: mmc@4809c000 { compatible = "ti,omap4-hsmmc"; reg = <0x4809c000 0x400>; ti,hwmods = "mmc1"; ti,dual-volt; bus-width = <4>; vmmc-supply = <&vmmc>; /* phandle to regulator node */ ti,non-removable; dmas = <&edma 24 &edma 25>; dma-names = "tx", "rx"; }; [workaround for missing swakeup on am33xx] This SOC is missing the swakeup line, it will not detect SDIO irq while in suspend. ------ | PRCM | ------ ^ | swakeup | | fclk | v ------ ------- ----- | card | -- CIRQ --> | hsmmc | -- IRQ --> | CPU | ------ ------- ----- In suspend the fclk is off and the module is dysfunctional. Even register reads will fail. A small logic in the host will request fclk restore, when an external event is detected. Once the clock is restored, the host detects the event normally. Since am33xx doesn't have this line it never wakes from suspend. The workaround is to reconfigure the dat1 line as a GPIO upon suspend. To make this work, we need to set the named pinctrl states "default" and "idle". Prepare idle to remux dat1 as a gpio, and default to remux it back as sdio dat1. The MMC driver will then toggle between idle and default state during runtime. In summary: 1. select matching 'compatible' section, see example below. 2. specify pinctrl states "default" and "idle", "sleep" is optional. 3. specify the gpio irq used for detecting sdio irq in suspend If configuration is incomplete, a warning message is emitted "falling back to polling". Also check the "sdio irq mode" in /sys/kernel/debug/mmc0/regs. Mind not every application needs SDIO irq, e.g. MMC cards. mmc1: mmc@48060100 { compatible = "ti,am33xx-hsmmc"; ... pinctrl-names = "default", "idle", "sleep" pinctrl-0 = <&mmc1_pins>; pinctrl-1 = <&mmc1_idle>; pinctrl-2 = <&mmc1_sleep>; ... interrupts-extended = <&intc 64 &gpio2 28 IRQ_TYPE_LEVEL_LOW>; }; mmc1_idle : pinmux_cirq_pin { pinctrl-single,pins = < 0x0f8 0x3f /* GPIO2_28 */ >; };