1 * TI Highspeed MMC host controller for OMAP and 66AK2G family.
2
3 The Highspeed MMC Host Controller on TI OMAP and 66AK2G family
4 provides an interface for MMC, SD, and SDIO types of memory cards.
5
6 This file documents differences between the core properties described
7 by mmc.txt and the properties used by the omap_hsmmc driver.
8
9 Required 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
19 SoC specific required properties:
20 ---------------------------------
21 The 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
24 The 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
36 Optional 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
54 Examples:
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
85 This SOC is missing the swakeup line, it will not detect SDIO irq
86 while in suspend.
87
88 ------
89 | PRCM |
90 ------
91 ^ |
92 swakeup | | fclk
93 | v
94 ------ ------- -----
95 | card | -- CIRQ --> | hsmmc | -- IRQ --> | CPU |
96 ------ ------- -----
97
98 In suspend the fclk is off and the module is dysfunctional. Even register reads
99 will fail. A small logic in the host will request fclk restore, when an
100 external event is detected. Once the clock is restored, the host detects the
101 event normally. Since am33xx doesn't have this line it never wakes from
102 suspend.
103
104 The workaround is to reconfigure the dat1 line as a GPIO upon suspend. To make
105 this work, we need to set the named pinctrl states "default" and "idle".
106 Prepare idle to remux dat1 as a gpio, and default to remux it back as sdio
107 dat1. The MMC driver will then toggle between idle and default state during
108 runtime.
109
110 In summary:
111 1. select matching 'compatible' section, see example below.
112 2. specify pinctrl states "default" and "idle", "sleep" is optional.
113 3. specify the gpio irq used for detecting sdio irq in suspend
114
115 If configuration is incomplete, a warning message is emitted "falling back to
116 polling". Also check the "sdio irq mode" in /sys/kernel/debug/mmc0/regs. Mind
117 not 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 };
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