I am having trouble understanding how to handle SD driver on my Vocore2 board.
I already managed to make it work under Linux (5.3.0). Root problem is VoCore2 has no support for power switching on the SD/MMC slot; a direct wire goes directly to the 3.3V supply.
Similar issue for the clock (here I needed a very ugly patch (below)).
Questions are twofold: 1) Is this really needed (on mainstream kernel) or did I miss some DT setting that would have achieved the same effect? 2) How to achieve equivalent effect on U-Boot .../mtk_sd.c which looks very different from the above?
If I do a "naive" porting SD will NOT work; any commands (e.g.: "mmc info") results in error: "mmc_init: -95, time 6201" (curiously always with the same "time") which I *think* I traced to inability to handle voltage changes.
Any hint would be very welcome.
Regards and Merry Christmas and very Happy New Year! Mauro
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From 3d239054fd01fbeb03863eee7eefd2a76b82dc02 Mon Sep 17 00:00:00 2001
From: Mauro Condarelli mc5686@mclink.it Date: Wed, 18 Sep 2019 14:07:22 +0200 Subject: [PATCH 8/8] MIPS, MMC, VoCore2: Preliminary fix for mtk-sd
--- arch/mips/boot/dts/ralink/mt7628a.dtsi | 37 ++++++++++++++++++++++++++ arch/mips/boot/dts/ralink/vocore2.dts | 4 +++ arch/mips/ralink/clk.c | 2 +- drivers/mmc/host/mtk-sd.c | 8 ++++++ 4 files changed, 50 insertions(+), 1 deletion(-)
diff --git a/arch/mips/boot/dts/ralink/mt7628a.dtsi b/arch/mips/boot/dts/ralink/mt7628a.dtsi index 376536489415..9636709edc5d 100644 --- a/arch/mips/boot/dts/ralink/mt7628a.dtsi +++ b/arch/mips/boot/dts/ralink/mt7628a.dtsi @@ -259,6 +259,43 @@ reset-names = "host", "device"; }; + clk48m: clk48m@0 { + compatible = "fixed-clock"; + clock-frequency = <48000000>; + #clock-cells = <0>; + }; + + vmmcsd_fixed: fixedregulator@0 { + compatible = "regulator-fixed"; + regulator-name = "vmmcsd_fixed"; + regulator-min-microvolt = <3300000>; + regulator-max-microvolt = <3300000>; + }; + + mmc: mmc@10130000 { + compatible = "mediatek,mt7620-mmc"; + reg = <0x10130000 0x4000>; + builtin-cd = <1>; + r_smpl = <1>; + + interrupt-parent = <&intc>; + interrupts = <14>; + + clocks = <&clk48m>, <&clk48m>; + clock-names = "source", "hclk"; + + pinctrl-names = "default", "state_uhs"; + pinctrl-0 = <&pinmux_sdmode_sdxc>; + pinctrl-1 = <&pinmux_sdmode_sdxc>; + + vmmc-supply = <&vmmcsd_fixed>; + vqmmc-supply = <&vmmcsd_fixed>; + + resets = <&resetc 30>; + + status = "disabled"; + }; + ehci@101c0000 { compatible = "generic-ehci"; reg = <0x101c0000 0x1000>; diff --git a/arch/mips/boot/dts/ralink/vocore2.dts b/arch/mips/boot/dts/ralink/vocore2.dts index 559c4256d48a..19e8ece4aa2a 100644 --- a/arch/mips/boot/dts/ralink/vocore2.dts +++ b/arch/mips/boot/dts/ralink/vocore2.dts @@ -62,3 +62,7 @@ status = "okay"; mediatek,mtd-eeprom = <&eeprom 0x0000>; }; + +&mmc { + status = "okay"; +}; diff --git a/arch/mips/ralink/clk.c b/arch/mips/ralink/clk.c index 0e57845d7f9a..930c2776f6fd 100644 --- a/arch/mips/ralink/clk.c +++ b/arch/mips/ralink/clk.c @@ -90,4 +90,4 @@ struct clk *clk_get_parent(struct clk *clk) { return NULL; } -EXPORT_SYMBOL(clk_get_parent); +EXPORT_SYMBOL_GPL(clk_get_parent); diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c index 33f4b6387ef7..13464161521c 100644 --- a/drivers/mmc/host/mtk-sd.c +++ b/drivers/mmc/host/mtk-sd.c @@ -721,18 +721,22 @@ static void msdc_set_timeout(struct msdc_host *host, u32 ns, u32 clks) static void msdc_gate_clock(struct msdc_host *host) { +#ifdef handle_clocks clk_disable_unprepare(host->src_clk_cg); clk_disable_unprepare(host->src_clk); clk_disable_unprepare(host->bus_clk); clk_disable_unprepare(host->h_clk); +#endif//handle_clocks } static void msdc_ungate_clock(struct msdc_host *host) { +#ifdef handle_clocks clk_prepare_enable(host->h_clk); clk_prepare_enable(host->bus_clk); clk_prepare_enable(host->src_clk); clk_prepare_enable(host->src_clk_cg); +#endif//handle_clocks while (!(readl(host->base + MSDC_CFG) & MSDC_CFG_CKSTB)) cpu_relax(); } @@ -2199,6 +2203,9 @@ static int msdc_drv_probe(struct platform_device *pdev) if (ret) goto host_free; + +#ifdef handle_clocks +#error "should NOT compile!" host->src_clk = devm_clk_get(&pdev->dev, "source"); if (IS_ERR(host->src_clk)) { ret = PTR_ERR(host->src_clk); @@ -2218,6 +2225,7 @@ static int msdc_drv_probe(struct platform_device *pdev) host->src_clk_cg = devm_clk_get(&pdev->dev, "source_cg"); if (IS_ERR(host->src_clk_cg)) host->src_clk_cg = NULL; +#endif //handle_clocks host->irq = platform_get_irq(pdev, 0); if (host->irq < 0) {