* TI Highspeed MMC host controller for OMAP The Highspeed MMC Host Controller on TI OMAP 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 - ti,hwmods: Must be "mmc", n is controller instance starting 1 Optional properties: ti,dual-volt: boolean, supports dual voltage cards -supply: phandle to the regulator device tree node "supply-name" examples are "vmmc", "vmmc_aux" 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@0x4809c000 { 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@0x4809c000 { 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 disfunctional. 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 0>; }; mmc1_idle : pinmux_cirq_pin { pinctrl-single,pins = < 0x0f8 0x3f /* GPIO2_28 */ >; };