[PATCH 0/3] Enable l3gd20 on stm32f429-disco board

From: dillon min <redacted>

This patchset is for enable l3gd20 on stm32f429-disco board
has following changes:

1, enable spi5 controller on stm32f429-disco (dts)
2, add spi5 pinmap for stm32f429-disco	(dts)
3, add SPI_SIMPLEX_RX, SPI_3WIRE_RX support for stm32f4


dillon min (3):
  ARM: dts: stm32: Add pin map for spi5 on stm32f429-disco board
  ARM: dts: stm32: enable l3gd20 on stm32429-disco board
  spi: stm32: Add SPI_SIMPLEX_RX, SPI_3WIRE_RX support for stm32f4

 arch/arm/boot/dts/stm32f4-pinctrl.dtsi | 17 +++++++++++++++++
 arch/arm/boot/dts/stm32f429-disco.dts  | 24 ++++++++++++++++++++++++
 drivers/spi/spi-stm32.c                | 29 +++++++++++++++++++++++++----
 3 files changed, 66 insertions(+), 4 deletions(-)

-- 
2.7.4

From: dillon min <redacted>

This patch adds the pin configuration for ltdc, spi5 controller
on stm32f429-disco board.

Signed-off-by: dillon min <redacted>
---
 arch/arm/boot/dts/stm32f4-pinctrl.dtsi | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/arch/arm/boot/dts/stm32f4-pinctrl.dtsi b/arch/arm/boot/dts/stm32f4-pinctrl.dtsi
index 392fa14..54c1b27 100644
--- a/arch/arm/boot/dts/stm32f4-pinctrl.dtsi
+++ b/arch/arm/boot/dts/stm32f4-pinctrl.dtsi

@@ -316,6 +316,23 @@
 				};
 			};
 
+			spi5_pins: spi5-0 {
+				pins1 {
+					pinmux = <STM32_PINMUX('F', 7, AF5)>,
+						/* SPI5_CLK */
+						 <STM32_PINMUX('F', 9, AF5)>;
+						/* SPI5_MOSI */
+					bias-disable;
+					drive-push-pull;
+					slew-rate = <0>;
+				};
+				pins2 {
+					pinmux = <STM32_PINMUX('F', 8, AF5)>;
+						/* SPI5_MISO */
+					bias-disable;
+				};
+			};
+
 			dcmi_pins: dcmi-0 {
 				pins {
 					pinmux = <STM32_PINMUX('A', 4, AF13)>, /* DCMI_HSYNC */

-- 
2.7.4

From: dillon min <redacted>

Enable l3gd20 on stm32429-disco board.

Signed-off-by: dillon min <redacted>
---
 arch/arm/boot/dts/stm32f429-disco.dts | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/arch/arm/boot/dts/stm32f429-disco.dts b/arch/arm/boot/dts/stm32f429-disco.dts
index 30c0f67..d365358 100644
--- a/arch/arm/boot/dts/stm32f429-disco.dts
+++ b/arch/arm/boot/dts/stm32f429-disco.dts

@@ -49,6 +49,8 @@
 #include "stm32f429.dtsi"
 #include "stm32f429-pinctrl.dtsi"
 #include <dt-bindings/input/input.h>
+#include <dt-bindings/interrupt-controller/irq.h>
+#include <dt-bindings/gpio/gpio.h>
 
 / {
 	model = "STMicroelectronics STM32F429i-DISCO board";

@@ -127,3 +129,25 @@
 	pinctrl-names = "default";
 	status = "okay";
 };
+
+&spi5 {
+	status = "okay";
+	pinctrl-0 = <&spi5_pins>;
+	pinctrl-names = "default";
+	#address-cells = <1>;
+	#size-cells = <0>;
+	cs-gpios = <&gpioc 1 GPIO_ACTIVE_LOW>;
+	dmas = <&dma2 3 2 0x400 0x0>,
+	       <&dma2 4 2 0x400 0x0>;
+	dma-names = "rx", "tx";
+	l3gd20: l3gd20@0 {
+		compatible = "st,l3gd20-gyro";
+		spi-max-frequency = <10000000>;
+		st,drdy-int-pin = <2>;
+		interrupt-parent = <&gpioa>;
+		interrupts = <1 IRQ_TYPE_EDGE_RISING>,
+				<2 IRQ_TYPE_EDGE_RISING>;
+		reg = <0>;
+		status = "okay";
+	};
+};

-- 
2.7.4

Hi

On 5/9/20 8:58 AM, dillon.minfei@gmail.com wrote:

From: dillon min <redacted>

Enable l3gd20 on stm32429-disco board.

You could add some words about l3gd20

Insert blank line here.

+	l3gd20: l3gd20@0 {
+		compatible = "st,l3gd20-gyro";
+		spi-max-frequency = <10000000>;
+		st,drdy-int-pin = <2>;
+		interrupt-parent = <&gpioa>;
+		interrupts = <1 IRQ_TYPE_EDGE_RISING>,
+				<2 IRQ_TYPE_EDGE_RISING>;
+		reg = <0>;
+		status = "okay";
+	};
+};

Hi, Alexandre,

Thanks for review.

On Mon, May 11, 2020 at 3:17 PM Alexandre Torgue
[off-list ref] wrote:

Hi

On 5/9/20 8:58 AM, dillon.minfei@gmail.com wrote:

quoted

From: dillon min <redacted>

Enable l3gd20 on stm32429-disco board.

You could add some words about l3gd20

ok, thanks, i will add some description about l3gd20.

quoted

Signed-off-by: dillon min <redacted>
---
  arch/arm/boot/dts/stm32f429-disco.dts | 24 ++++++++++++++++++++++++
  1 file changed, 24 insertions(+)

diff --git a/arch/arm/boot/dts/stm32f429-disco.dts b/arch/arm/boot/dts/stm32f429-disco.dts
index 30c0f67..d365358 100644
--- a/arch/arm/boot/dts/stm32f429-disco.dts
+++ b/arch/arm/boot/dts/stm32f429-disco.dts

@@ -49,6 +49,8 @@
  #include "stm32f429.dtsi"
  #include "stm32f429-pinctrl.dtsi"
  #include <dt-bindings/input/input.h>
+#include <dt-bindings/interrupt-controller/irq.h>
+#include <dt-bindings/gpio/gpio.h>

  / {
      model = "STMicroelectronics STM32F429i-DISCO board";

@@ -127,3 +129,25 @@
      pinctrl-names = "default";
      status = "okay";
  };
+
+&spi5 {
+     status = "okay";
+     pinctrl-0 = <&spi5_pins>;
+     pinctrl-names = "default";
+     #address-cells = <1>;
+     #size-cells = <0>;
+     cs-gpios = <&gpioc 1 GPIO_ACTIVE_LOW>;
+     dmas = <&dma2 3 2 0x400 0x0>,
+            <&dma2 4 2 0x400 0x0>;
+     dma-names = "rx", "tx";

Insert blank line here.

ok

quoted

+     l3gd20: l3gd20@0 {
+             compatible = "st,l3gd20-gyro";
+             spi-max-frequency = <10000000>;
+             st,drdy-int-pin = <2>;
+             interrupt-parent = <&gpioa>;
+             interrupts = <1 IRQ_TYPE_EDGE_RISING>,
+                             <2 IRQ_TYPE_EDGE_RISING>;
+             reg = <0>;
+             status = "okay";
+     };
+};

From: dillon min <redacted>

in l3gd20 driver startup, there is a setup failed error return from
stm32 spi driver

"
[    2.687630] st-gyro-spi spi0.0: supply vdd not found, using dummy
regulator
[    2.696869] st-gyro-spi spi0.0: supply vddio not found, using dummy
regulator
[    2.706707] spi_stm32 40015000.spi: SPI transfer setup failed
[    2.713741] st-gyro-spi spi0.0: SPI transfer failed: -22
[    2.721096] spi_master spi0: failed to transfer one message from queue
[    2.729268] iio iio:device0: failed to read Who-Am-I register.
[    2.737504] st-gyro-spi: probe of spi0.0 failed with error -22
"

after debug into spi-stm32 driver, st-gyro-spi split two steps to read
l3gd20 id

first: send command to l3gd20 with read id command in tx_buf, rx_buf
is null.
second: read id with tx_buf is null, rx_buf not null.

so, for second step, stm32 driver recongise this process is SPI_SIMPLE_RX
from stm32_spi_communication_type, but there is no related process for this
type in stm32f4_spi_set_mode, then we get error from
stm32_spi_transfer_one_setup.

we can use two method to fix this bug.
1, use stm32 spi's "In unidirectional receive-only mode (BIDIMODE=0 and
RXONLY=1)". but as our code running in sdram, the read latency is too large
to get so many receive overrun error in interrupts handler.

2, use stm32 spi's "In full-duplex (BIDIMODE=0 and RXONLY=0)", as tx_buf is
null, we must add dummy data sent out before read data.
so, add stm32f4_spi_tx_dummy to handle this situation.

Signed-off-by: dillon min <redacted>
---
 drivers/spi/spi-stm32.c | 29 +++++++++++++++++++++++++----
 1 file changed, 25 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c
index 44ac6eb3..bcf1ba7 100644
--- a/drivers/spi/spi-stm32.c
+++ b/drivers/spi/spi-stm32.c

@@ -388,6 +388,13 @@ static int stm32h7_spi_get_fifo_size(struct stm32_spi *spi)
 	return count;
 }
 
+static void stm32f4_spi_tx_dummy(struct stm32_spi *spi)
+{
+	if (spi->cur_bpw == 16)
+		writew_relaxed(0x5555, spi->base + STM32F4_SPI_DR);
+	else
+		writeb_relaxed(0x55, spi->base + STM32F4_SPI_DR);
+}
 /**
  * stm32f4_spi_get_bpw_mask - Return bits per word mask
  * @spi: pointer to the spi controller data structure

@@ -811,7 +818,9 @@ static irqreturn_t stm32f4_spi_irq_event(int irq, void *dev_id)
 		mask |= STM32F4_SPI_SR_TXE;
 	}
 
-	if (!spi->cur_usedma && spi->cur_comm == SPI_FULL_DUPLEX) {
+	if (!spi->cur_usedma && (spi->cur_comm == SPI_FULL_DUPLEX ||
+				 spi->cur_comm == SPI_SIMPLEX_RX ||
+				 spi->cur_comm == SPI_3WIRE_RX)) {
 		/* TXE flag is set and is handled when RXNE flag occurs */
 		sr &= ~STM32F4_SPI_SR_TXE;
 		mask |= STM32F4_SPI_SR_RXNE | STM32F4_SPI_SR_OVR;

@@ -850,8 +859,10 @@ static irqreturn_t stm32f4_spi_irq_event(int irq, void *dev_id)
 		stm32f4_spi_read_rx(spi);
 		if (spi->rx_len == 0)
 			end = true;
-		else /* Load data for discontinuous mode */
+		else if (spi->tx_buf)/* Load data for discontinuous mode */
 			stm32f4_spi_write_tx(spi);
+		else if (spi->cur_comm == SPI_SIMPLEX_RX)
+			stm32f4_spi_tx_dummy(spi);
 	}
 
 end_irq:

@@ -1151,7 +1162,9 @@ static int stm32f4_spi_transfer_one_irq(struct stm32_spi *spi)
 	/* Enable the interrupts relative to the current communication mode */
 	if (spi->cur_comm == SPI_SIMPLEX_TX || spi->cur_comm == SPI_3WIRE_TX) {
 		cr2 |= STM32F4_SPI_CR2_TXEIE;
-	} else if (spi->cur_comm == SPI_FULL_DUPLEX) {
+	} else if (spi->cur_comm == SPI_FULL_DUPLEX ||
+				spi->cur_comm == SPI_SIMPLEX_RX ||
+				spi->cur_comm == SPI_3WIRE_RX) {
 		/* In transmit-only mode, the OVR flag is set in the SR register
 		 * since the received data are never read. Therefore set OVR
 		 * interrupt only when rx buffer is available.

@@ -1170,6 +1183,8 @@ static int stm32f4_spi_transfer_one_irq(struct stm32_spi *spi)
 	/* starting data transfer when buffer is loaded */
 	if (spi->tx_buf)
 		stm32f4_spi_write_tx(spi);
+	else if (spi->cur_comm == SPI_SIMPLEX_RX)
+		stm32f4_spi_tx_dummy(spi);
 
 	spin_unlock_irqrestore(&spi->lock, flags);
 

@@ -1462,10 +1477,16 @@ static int stm32f4_spi_set_mode(struct stm32_spi *spi, unsigned int comm_type)
 		stm32_spi_set_bits(spi, STM32F4_SPI_CR1,
 					STM32F4_SPI_CR1_BIDIMODE |
 					STM32F4_SPI_CR1_BIDIOE);
-	} else if (comm_type == SPI_FULL_DUPLEX) {
+	} else if (comm_type == SPI_FULL_DUPLEX ||
+				comm_type == SPI_SIMPLEX_RX) {
 		stm32_spi_clr_bits(spi, STM32F4_SPI_CR1,
 					STM32F4_SPI_CR1_BIDIMODE |
 					STM32F4_SPI_CR1_BIDIOE);
+	} else if (comm_type == SPI_3WIRE_RX) {
+		stm32_spi_set_bits(spi, STM32F4_SPI_CR1,
+					STM32F4_SPI_CR1_BIDIMODE);
+		stm32_spi_clr_bits(spi, STM32F4_SPI_CR1,
+					STM32F4_SPI_CR1_BIDIOE);
 	} else {
 		return -EINVAL;
 	}

-- 
2.7.4