[PATCH 1/4] mmc: mmci: Add bindings to operate CMD, CK, CKIN pins as GPIO

[PATCH 1/4] mmc: mmci: Add bindings to operate CMD, CK, CKIN pins as GPIO

[Marek Vasut]

Add DT bindings to describe GPIO line associated with CMD, CK, CKIN pins.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Ludovic Barre <ludovic.barre@st.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: linux-stm32@st-md-mailman.stormreply.com
Cc: devicetree@vger.kernel.org
---
NOTE: Depends on mmc: mmci: Convert bindings to DT schema
---
 .../devicetree/bindings/mmc/arm,pl18x.yaml    | 20 +++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/Documentation/devicetree/bindings/mmc/arm,pl18x.yaml b/Documentation/devicetree/bindings/mmc/arm,pl18x.yaml
index 0129d622fb67..0908dbeaa472 100644
--- a/Documentation/devicetree/bindings/mmc/arm,pl18x.yaml
+++ b/Documentation/devicetree/bindings/mmc/arm,pl18x.yaml
@@ -132,6 +132,26 @@ properties:
       driver to sample the receive data (for example with a voltage switch
       transceiver).
 
+  st,cmd-gpios:
+    maxItems: 1
+    description:
+      The GPIO matching the CMD pin.
+
+  st,ck-gpios:
+    maxItems: 1
+    description:
+      The GPIO matching the CK pin.
+
+  st,ckin-gpios:
+    maxItems: 1
+    description:
+      The GPIO matching the CKIN pin.
+
+dependencies:
+  st,cmd-gpios: [ "st,use-ckin" ]
+  st,ck-gpios: [ "st,use-ckin" ]
+  st,ckin-gpios: [ "st,use-ckin" ]
+
 additionalProperties: true
 
 required:
-- 
2.29.2

[PATCH 2/4] mmc: mmci: Add support for probing bus voltage level translator

[Marek Vasut]

Add support for testing whether bus voltage level translator is present
and operational. This is useful on systems where the bus voltage level
translator is optional, as the translator can be auto-detected by the
driver and the feedback clock functionality can be disabled if it is
not present.

This requires additional pinmux state, "init", where the CMD, CK, CKIN
lines are not configured, so they can be claimed as GPIOs early on in
probe(). The translator test sets CMD high to avoid interfering with a
card, and then verifies whether signal set on CK is detected on CKIN.
If the signal is detected, translator is present, otherwise the CKIN
feedback clock are disabled.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Ludovic Barre <ludovic.barre@st.com>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: linux-stm32@st-md-mailman.stormreply.com
---
 drivers/mmc/host/mmci.c | 70 ++++++++++++++++++++++++++++++++++++++---
 1 file changed, 65 insertions(+), 5 deletions(-)

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index b5a41a7ce165..1bc674577ff9 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -36,6 +36,7 @@
 #include <linux/types.h>
 #include <linux/pinctrl/consumer.h>
 #include <linux/reset.h>
+#include <linux/gpio/consumer.h>
 
 #include <asm/div64.h>
 #include <asm/io.h>
@@ -1888,6 +1889,65 @@ static struct mmc_host_ops mmci_ops = {
 	.start_signal_voltage_switch = mmci_sig_volt_switch,
 };
 
+static void mmci_probe_level_translator(struct mmc_host *mmc)
+{
+	struct device *dev = mmc_dev(mmc);
+	struct mmci_host *host = mmc_priv(mmc);
+	struct gpio_desc *cmd_gpio;
+	struct gpio_desc *ck_gpio;
+	struct gpio_desc *ckin_gpio;
+	int clk_hi, clk_lo;
+
+	/*
+	 * Assume the level translator is present if st,use-ckin is set.
+	 * This is to cater for DTs which do not implement this test.
+	 */
+	host->clk_reg_add |= MCI_STM32_CLK_SELCKIN;
+
+	cmd_gpio = gpiod_get(dev, "st,cmd", GPIOD_OUT_HIGH);
+	if (IS_ERR(cmd_gpio))
+		goto exit_cmd;
+
+	ck_gpio = gpiod_get(dev, "st,ck", GPIOD_OUT_HIGH);
+	if (IS_ERR(ck_gpio))
+		goto exit_ck;
+
+	ckin_gpio = gpiod_get(dev, "st,ckin", GPIOD_IN);
+	if (IS_ERR(ckin_gpio))
+		goto exit_ckin;
+
+	/* All GPIOs are valid, test whether level translator works */
+
+	/* Sample CKIN */
+	clk_hi = !!gpiod_get_value(ckin_gpio);
+
+	/* Set CK low */
+	gpiod_set_value(ck_gpio, 0);
+
+	/* Sample CKIN */
+	clk_lo = !!gpiod_get_value(ckin_gpio);
+
+	/* Tristate all */
+	gpiod_direction_input(cmd_gpio);
+	gpiod_direction_input(ck_gpio);
+
+	/* Level translator is present if CK signal is propagated to CKIN */
+	if (!clk_hi || clk_lo) {
+		host->clk_reg_add &= ~MCI_STM32_CLK_SELCKIN;
+		dev_warn(dev,
+			 "Level translator inoperable, CK signal not detected on CKIN, disabling.\n");
+	}
+
+	gpiod_put(ckin_gpio);
+
+exit_ckin:
+	gpiod_put(ck_gpio);
+exit_ck:
+	gpiod_put(cmd_gpio);
+exit_cmd:
+	pinctrl_select_default_state(dev);
+}
+
 static int mmci_of_parse(struct device_node *np, struct mmc_host *mmc)
 {
 	struct mmci_host *host = mmc_priv(mmc);
@@ -1913,7 +1973,7 @@ static int mmci_of_parse(struct device_node *np, struct mmc_host *mmc)
 	if (of_get_property(np, "st,neg-edge", NULL))
 		host->clk_reg_add |= MCI_STM32_CLK_NEGEDGE;
 	if (of_get_property(np, "st,use-ckin", NULL))
-		host->clk_reg_add |= MCI_STM32_CLK_SELCKIN;
+		mmci_probe_level_translator(mmc);
 
 	if (of_get_property(np, "mmc-cap-mmc-highspeed", NULL))
 		mmc->caps |= MMC_CAP_MMC_HIGHSPEED;
@@ -1949,15 +2009,15 @@ static int mmci_probe(struct amba_device *dev,
 	if (!mmc)
 		return -ENOMEM;
 
-	ret = mmci_of_parse(np, mmc);
-	if (ret)
-		goto host_free;
-
 	host = mmc_priv(mmc);
 	host->mmc = mmc;
 	host->mmc_ops = &mmci_ops;
 	mmc->ops = &mmci_ops;
 
+	ret = mmci_of_parse(np, mmc);
+	if (ret)
+		goto host_free;
+
 	/*
 	 * Some variant (STM32) doesn't have opendrain bit, nevertheless
 	 * pins can be set accordingly using pinctrl
-- 
2.29.2

Re: [PATCH 2/4] mmc: mmci: Add support for probing bus voltage level translator

[Linus Walleij]

On Sat, Jan 16, 2021 at 7:04 PM Marek Vasut <marex@denx.de> wrote:

> Add support for testing whether bus voltage level translator is present
> and operational. This is useful on systems where the bus voltage level
> translator is optional, as the translator can be auto-detected by the
> driver and the feedback clock functionality can be disabled if it is
> not present.
>
> This requires additional pinmux state, "init", where the CMD, CK, CKIN
> lines are not configured, so they can be claimed as GPIOs early on in
> probe(). The translator test sets CMD high to avoid interfering with a
> card, and then verifies whether signal set on CK is detected on CKIN.
> If the signal is detected, translator is present, otherwise the CKIN
> feedback clock are disabled.
>
> Signed-off-by: Marek Vasut <marex@denx.de>
> Cc: Alexandre Torgue <alexandre.torgue@st.com>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Cc: Ludovic Barre <ludovic.barre@st.com>
> Cc: Ulf Hansson <ulf.hansson@linaro.org>
> Cc: linux-stm32@st-md-mailman.stormreply.com

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij

Re: [Linux-stm32] [PATCH 2/4] mmc: mmci: Add support for probing bus voltage level translator

[Yann GAUTIER]

On 1/16/21 7:04 PM, Marek Vasut wrote:
> Add support for testing whether bus voltage level translator is present
> and operational. This is useful on systems where the bus voltage level
> translator is optional, as the translator can be auto-detected by the
> driver and the feedback clock functionality can be disabled if it is
> not present.
> 
> This requires additional pinmux state, "init", where the CMD, CK, CKIN
> lines are not configured, so they can be claimed as GPIOs early on in
> probe(). The translator test sets CMD high to avoid interfering with a
> card, and then verifies whether signal set on CK is detected on CKIN.
> If the signal is detected, translator is present, otherwise the CKIN
> feedback clock are disabled.
> 
> Signed-off-by: Marek Vasut<marex@denx.de>
> Cc: Alexandre Torgue<alexandre.torgue@st.com>
> Cc: Linus Walleij<linus.walleij@linaro.org>
> Cc: Ludovic Barre<ludovic.barre@st.com>
> Cc: Ulf Hansson<ulf.hansson@linaro.org>
> Cc:linux-stm32@st-md-mailman.stormreply.com

Hi Marek,

I've tested it on STM32MP157C-EV1 (which uses st,use-ckin) and 
STM32MP157C-DK2 (which doesn't). The mmc_test sessions are OK on both 
boards.
Feel free to add my:
Tested-by: Yann Gautier <yann.gautier@foss.st.com>


Regards,
Yann

[PATCH 3/4] ARM: dts: stm32: Add additional init state for SDMMC1 pins

[Marek Vasut]

Add "init" mux option for SDMMC1, where the CMD, CK, CKIN lines are not
configured, so they can be claimed as GPIOs early on in driver probe().
This is used for probing optional voltage level translator.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Ludovic Barre <ludovic.barre@st.com>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: linux-stm32@st-md-mailman.stormreply.com
---
 arch/arm/boot/dts/stm32mp15-pinctrl.dtsi | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/arch/arm/boot/dts/stm32mp15-pinctrl.dtsi b/arch/arm/boot/dts/stm32mp15-pinctrl.dtsi
index d8297dfff3e6..687f3534ba22 100644
--- a/arch/arm/boot/dts/stm32mp15-pinctrl.dtsi
+++ b/arch/arm/boot/dts/stm32mp15-pinctrl.dtsi
@@ -1385,6 +1385,18 @@ pins {
 		};
 	};
 
+	sdmmc1_b4_init_pins_a: sdmmc1-b4-init-0 {
+		pins1 {
+			pinmux = <STM32_PINMUX('C', 8, AF12)>, /* SDMMC1_D0 */
+				 <STM32_PINMUX('C', 9, AF12)>, /* SDMMC1_D1 */
+				 <STM32_PINMUX('C', 10, AF12)>, /* SDMMC1_D2 */
+				 <STM32_PINMUX('C', 11, AF12)>; /* SDMMC1_D3 */
+			slew-rate = <1>;
+			drive-push-pull;
+			bias-disable;
+		};
+	};
+
 	sdmmc1_dir_pins_a: sdmmc1-dir-0 {
 		pins1 {
 			pinmux = <STM32_PINMUX('F', 2, AF11)>, /* SDMMC1_D0DIR */
@@ -1409,6 +1421,17 @@ pins {
 		};
 	};
 
+	sdmmc1_dir_init_pins_a: sdmmc1-dir-init-0 {
+		pins1 {
+			pinmux = <STM32_PINMUX('F', 2, AF11)>, /* SDMMC1_D0DIR */
+				 <STM32_PINMUX('C', 7, AF8)>, /* SDMMC1_D123DIR */
+				 <STM32_PINMUX('B', 9, AF11)>; /* SDMMC1_CDIR */
+			slew-rate = <1>;
+			drive-push-pull;
+			bias-pull-up;
+		};
+	};
+
 	sdmmc1_dir_pins_b: sdmmc1-dir-1 {
 		pins1 {
 			pinmux = <STM32_PINMUX('F', 2, AF11)>, /* SDMMC1_D0DIR */
-- 
2.29.2

[PATCH 4/4] ARM: dts: stm32: Enable voltage translator auto-detection on DHCOM

[Marek Vasut]

The DHCOM SoM uSD slot has an optional voltage level translator, add
DT bindings which permit the MMCI driver to detect the translator
automatically.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Ludovic Barre <ludovic.barre@st.com>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: linux-stm32@st-md-mailman.stormreply.com
---
 arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi b/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi
index ff70bd03a017..661d8d071296 100644
--- a/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi
+++ b/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi
@@ -408,14 +408,19 @@ &rtc {
 };
 
 &sdmmc1 {
-	pinctrl-names = "default", "opendrain", "sleep";
+	pinctrl-names = "default", "opendrain", "sleep", "init";
 	pinctrl-0 = <&sdmmc1_b4_pins_a &sdmmc1_dir_pins_a>;
 	pinctrl-1 = <&sdmmc1_b4_od_pins_a &sdmmc1_dir_pins_a>;
 	pinctrl-2 = <&sdmmc1_b4_sleep_pins_a &sdmmc1_dir_sleep_pins_a>;
+	pinctrl-3 = <&sdmmc1_b4_init_pins_a &sdmmc1_dir_init_pins_a>;
 	cd-gpios = <&gpiog 1 (GPIO_ACTIVE_LOW | GPIO_PULL_UP)>;
 	disable-wp;
 	st,sig-dir;
 	st,neg-edge;
+	st,use-ckin;
+	st,cmd-gpios = <&gpiod 2 0>;
+	st,ck-gpios = <&gpioc 12 0>;
+	st,ckin-gpios = <&gpioe 4 0>;
 	bus-width = <4>;
 	vmmc-supply = <&vdd_sd>;
 	status = "okay";
-- 
2.29.2