1* TI Highspeed MMC host controller for OMAP and 66AK2G family. 2 3The Highspeed MMC Host Controller on TI OMAP and 66AK2G family 4provides an interface for MMC, SD, and SDIO types of memory cards. 5 6This file documents differences between the core properties described 7by mmc.txt and the properties used by the omap_hsmmc driver. 8 9Required properties: 10-------------------- 11- compatible: 12 Should be "ti,omap2-hsmmc", for OMAP2 controllers 13 Should be "ti,omap3-hsmmc", for OMAP3 controllers 14 Should be "ti,omap3-pre-es3-hsmmc" for OMAP3 controllers pre ES3.0 15 Should be "ti,omap4-hsmmc", for OMAP4 controllers 16 Should be "ti,am33xx-hsmmc", for AM335x controllers 17 Should be "ti,k2g-hsmmc", "ti,omap4-hsmmc" for 66AK2G controllers. 18 19SoC specific required properties: 20--------------------------------- 21The following are mandatory properties for OMAPs, AM33xx and AM43xx SoCs only: 22- ti,hwmods: Must be "mmc<n>", n is controller instance starting 1. 23 24The following are mandatory properties for 66AK2G SoCs only: 25- power-domains:Should contain a phandle to a PM domain provider node 26 and an args specifier containing the MMC device id 27 value. This property is as per the binding, 28 Documentation/devicetree/bindings/soc/ti/sci-pm-domain.yaml 29- clocks: Must contain an entry for each entry in clock-names. Should 30 be defined as per the he appropriate clock bindings consumer 31 usage in Documentation/devicetree/bindings/clock/ti,sci-clk.yaml 32- clock-names: Shall be "fck" for the functional clock, 33 and "mmchsdb_fck" for the debounce clock. 34 35 36Optional properties: 37-------------------- 38- ti,dual-volt: boolean, supports dual voltage cards 39- <supply-name>-supply: phandle to the regulator device tree node 40 "supply-name" examples are "vmmc", 41 "vmmc_aux"(deprecated)/"vqmmc" etc 42- ti,non-removable: non-removable slot (like eMMC) 43- ti,needs-special-reset: Requires a special softreset sequence 44- ti,needs-special-hs-handling: HSMMC IP needs special setting 45 for handling High Speed 46- dmas: List of DMA specifiers with the controller specific 47 format as described in the generic DMA client 48 binding. A tx and rx specifier is required. 49- dma-names: List of DMA request names. These strings correspond 50 1:1 with the DMA specifiers listed in dmas. 51 The string naming is to be "rx" and "tx" for 52 RX and TX DMA requests, respectively. 53 54Examples: 55 56[hwmod populated DMA resources] 57 58 mmc1: mmc@4809c000 { 59 compatible = "ti,omap4-hsmmc"; 60 reg = <0x4809c000 0x400>; 61 ti,hwmods = "mmc1"; 62 ti,dual-volt; 63 bus-width = <4>; 64 vmmc-supply = <&vmmc>; /* phandle to regulator node */ 65 ti,non-removable; 66 }; 67 68[generic DMA request binding] 69 70 mmc1: mmc@4809c000 { 71 compatible = "ti,omap4-hsmmc"; 72 reg = <0x4809c000 0x400>; 73 ti,hwmods = "mmc1"; 74 ti,dual-volt; 75 bus-width = <4>; 76 vmmc-supply = <&vmmc>; /* phandle to regulator node */ 77 ti,non-removable; 78 dmas = <&edma 24 79 &edma 25>; 80 dma-names = "tx", "rx"; 81 }; 82 83[workaround for missing swakeup on am33xx] 84 85This SOC is missing the swakeup line, it will not detect SDIO irq 86while in suspend. 87 88 ------ 89 | PRCM | 90 ------ 91 ^ | 92 swakeup | | fclk 93 | v 94 ------ ------- ----- 95 | card | -- CIRQ --> | hsmmc | -- IRQ --> | CPU | 96 ------ ------- ----- 97 98In suspend the fclk is off and the module is dysfunctional. Even register reads 99will fail. A small logic in the host will request fclk restore, when an 100external event is detected. Once the clock is restored, the host detects the 101event normally. Since am33xx doesn't have this line it never wakes from 102suspend. 103 104The workaround is to reconfigure the dat1 line as a GPIO upon suspend. To make 105this work, we need to set the named pinctrl states "default" and "idle". 106Prepare idle to remux dat1 as a gpio, and default to remux it back as sdio 107dat1. The MMC driver will then toggle between idle and default state during 108runtime. 109 110In summary: 1111. select matching 'compatible' section, see example below. 1122. specify pinctrl states "default" and "idle", "sleep" is optional. 1133. specify the gpio irq used for detecting sdio irq in suspend 114 115If configuration is incomplete, a warning message is emitted "falling back to 116polling". Also check the "sdio irq mode" in /sys/kernel/debug/mmc0/regs. Mind 117not every application needs SDIO irq, e.g. MMC cards. 118 119 mmc1: mmc@48060100 { 120 compatible = "ti,am33xx-hsmmc"; 121 ... 122 pinctrl-names = "default", "idle", "sleep" 123 pinctrl-0 = <&mmc1_pins>; 124 pinctrl-1 = <&mmc1_idle>; 125 pinctrl-2 = <&mmc1_sleep>; 126 ... 127 interrupts-extended = <&intc 64 &gpio2 28 IRQ_TYPE_LEVEL_LOW>; 128 }; 129 130 mmc1_idle : pinmux_cirq_pin { 131 pinctrl-single,pins = < 132 0x0f8 0x3f /* GPIO2_28 */ 133 >; 134 }; 135