0001 * TI Highspeed MMC host controller for OMAP and 66AK2G family.
0002
0003 The Highspeed MMC Host Controller on TI OMAP and 66AK2G family
0004 provides an interface for MMC, SD, and SDIO types of memory cards.
0005
0006 This file documents differences between the core properties described
0007 by mmc.txt and the properties used by the omap_hsmmc driver.
0008
0009 Required properties:
0010 --------------------
0011 - compatible:
0012 Should be "ti,omap2-hsmmc", for OMAP2 controllers
0013 Should be "ti,omap3-hsmmc", for OMAP3 controllers
0014 Should be "ti,omap3-pre-es3-hsmmc" for OMAP3 controllers pre ES3.0
0015 Should be "ti,omap4-hsmmc", for OMAP4 controllers
0016 Should be "ti,am33xx-hsmmc", for AM335x controllers
0017 Should be "ti,k2g-hsmmc", "ti,omap4-hsmmc" for 66AK2G controllers.
0018
0019 SoC specific required properties:
0020 ---------------------------------
0021 The following are mandatory properties for OMAPs, AM33xx and AM43xx SoCs only:
0022 - ti,hwmods: Must be "mmc<n>", n is controller instance starting 1.
0023
0024 The following are mandatory properties for 66AK2G SoCs only:
0025 - power-domains:Should contain a phandle to a PM domain provider node
0026 and an args specifier containing the MMC device id
0027 value. This property is as per the binding,
0028 Documentation/devicetree/bindings/soc/ti/sci-pm-domain.yaml
0029 - clocks: Must contain an entry for each entry in clock-names. Should
0030 be defined as per the he appropriate clock bindings consumer
0031 usage in Documentation/devicetree/bindings/clock/ti,sci-clk.yaml
0032 - clock-names: Shall be "fck" for the functional clock,
0033 and "mmchsdb_fck" for the debounce clock.
0034
0035
0036 Optional properties:
0037 --------------------
0038 - ti,dual-volt: boolean, supports dual voltage cards
0039 - <supply-name>-supply: phandle to the regulator device tree node
0040 "supply-name" examples are "vmmc",
0041 "vmmc_aux"(deprecated)/"vqmmc" etc
0042 - ti,non-removable: non-removable slot (like eMMC)
0043 - ti,needs-special-reset: Requires a special softreset sequence
0044 - ti,needs-special-hs-handling: HSMMC IP needs special setting
0045 for handling High Speed
0046 - dmas: List of DMA specifiers with the controller specific
0047 format as described in the generic DMA client
0048 binding. A tx and rx specifier is required.
0049 - dma-names: List of DMA request names. These strings correspond
0050 1:1 with the DMA specifiers listed in dmas.
0051 The string naming is to be "rx" and "tx" for
0052 RX and TX DMA requests, respectively.
0053
0054 Examples:
0055
0056 [hwmod populated DMA resources]
0057
0058 mmc1: mmc@4809c000 {
0059 compatible = "ti,omap4-hsmmc";
0060 reg = <0x4809c000 0x400>;
0061 ti,hwmods = "mmc1";
0062 ti,dual-volt;
0063 bus-width = <4>;
0064 vmmc-supply = <&vmmc>; /* phandle to regulator node */
0065 ti,non-removable;
0066 };
0067
0068 [generic DMA request binding]
0069
0070 mmc1: mmc@4809c000 {
0071 compatible = "ti,omap4-hsmmc";
0072 reg = <0x4809c000 0x400>;
0073 ti,hwmods = "mmc1";
0074 ti,dual-volt;
0075 bus-width = <4>;
0076 vmmc-supply = <&vmmc>; /* phandle to regulator node */
0077 ti,non-removable;
0078 dmas = <&edma 24
0079 &edma 25>;
0080 dma-names = "tx", "rx";
0081 };
0082
0083 [workaround for missing swakeup on am33xx]
0084
0085 This SOC is missing the swakeup line, it will not detect SDIO irq
0086 while in suspend.
0087
0088 ------
0089 | PRCM |
0090 ------
0091 ^ |
0092 swakeup | | fclk
0093 | v
0094 ------ ------- -----
0095 | card | -- CIRQ --> | hsmmc | -- IRQ --> | CPU |
0096 ------ ------- -----
0097
0098 In suspend the fclk is off and the module is disfunctional. Even register reads
0099 will fail. A small logic in the host will request fclk restore, when an
0100 external event is detected. Once the clock is restored, the host detects the
0101 event normally. Since am33xx doesn't have this line it never wakes from
0102 suspend.
0103
0104 The workaround is to reconfigure the dat1 line as a GPIO upon suspend. To make
0105 this work, we need to set the named pinctrl states "default" and "idle".
0106 Prepare idle to remux dat1 as a gpio, and default to remux it back as sdio
0107 dat1. The MMC driver will then toggle between idle and default state during
0108 runtime.
0109
0110 In summary:
0111 1. select matching 'compatible' section, see example below.
0112 2. specify pinctrl states "default" and "idle", "sleep" is optional.
0113 3. specify the gpio irq used for detecting sdio irq in suspend
0114
0115 If configuration is incomplete, a warning message is emitted "falling back to
0116 polling". Also check the "sdio irq mode" in /sys/kernel/debug/mmc0/regs. Mind
0117 not every application needs SDIO irq, e.g. MMC cards.
0118
0119 mmc1: mmc@48060100 {
0120 compatible = "ti,am33xx-hsmmc";
0121 ...
0122 pinctrl-names = "default", "idle", "sleep"
0123 pinctrl-0 = <&mmc1_pins>;
0124 pinctrl-1 = <&mmc1_idle>;
0125 pinctrl-2 = <&mmc1_sleep>;
0126 ...
0127 interrupts-extended = <&intc 64 &gpio2 28 IRQ_TYPE_LEVEL_LOW>;
0128 };
0129
0130 mmc1_idle : pinmux_cirq_pin {
0131 pinctrl-single,pins = <
0132 0x0f8 0x3f /* GPIO2_28 */
0133 >;
0134 };
