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
=========================================================================
>From 3d239054fd01fbeb03863eee7eefd2a76b82dc02 Mon Sep 17 00:00:00 2001
From: Mauro Condarelli <mc5...@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) {
--
2.23.0
