[PATCH v2 0/5] Add i2c bus recovery support for Atmel SoCs

[PATCH v2 0/5] Add i2c bus recovery support for Atmel SoCs

[Kamel Bouhara]

Some Atmel SoCs actually doesn't support the clear command for recovery.
This patch serie merge the two support for both i2c bus recovery
mechanism (clear command and gpio/pinctrl).

Codrin Ciubotariu (1):
  i2c: at91: Send bus clear command if SCL or SDA is down

Kamel Bouhara (4):
  dt-bindings: i2c: at91: document optional bus recovery properties
  i2c: at91: implement i2c bus recovery
  ARM: at91/dt: sama5d3: add i2c gpio pinctrl
  ARM: at91/dt: sama5d4: add i2c gpio pinctrl

 .../devicetree/bindings/i2c/i2c-at91.txt      | 10 +++
 arch/arm/boot/dts/sama5d3.dtsi                | 33 ++++++-
 arch/arm/boot/dts/sama5d4.dtsi                | 33 ++++++-
 drivers/i2c/busses/i2c-at91-core.c            |  8 ++
 drivers/i2c/busses/i2c-at91-master.c          | 86 +++++++++++++++++++
 drivers/i2c/busses/i2c-at91.h                 | 15 +++-
 6 files changed, 178 insertions(+), 7 deletions(-)

--
2.23.0

[PATCH v2 1/5] i2c: at91: Send bus clear command if SCL or SDA is down

[Kamel Bouhara]

From: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>

After a transfer timeout, some faulty I2C slave devices might hold down
the SCL or the SDA pins. We can generate a bus clear command, hoping that
the slave might release the pins.

Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
---
 drivers/i2c/busses/i2c-at91-core.c   |  8 ++++++++
 drivers/i2c/busses/i2c-at91-master.c | 22 ++++++++++++++++++++++
 drivers/i2c/busses/i2c-at91.h        |  7 ++++++-
 3 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-at91-core.c b/drivers/i2c/busses/i2c-at91-core.c
index 435c7d7377a3..cb07489e698f 100644
--- a/drivers/i2c/busses/i2c-at91-core.c
+++ b/drivers/i2c/busses/i2c-at91-core.c
@@ -68,6 +68,7 @@ static struct at91_twi_pdata at91rm9200_config = {
 	.has_unre_flag = true,
 	.has_alt_cmd = false,
 	.has_hold_field = false,
+	.has_clear_cmd = false,
 };
 
 static struct at91_twi_pdata at91sam9261_config = {
@@ -76,6 +77,7 @@ static struct at91_twi_pdata at91sam9261_config = {
 	.has_unre_flag = false,
 	.has_alt_cmd = false,
 	.has_hold_field = false,
+	.has_clear_cmd = false,
 };
 
 static struct at91_twi_pdata at91sam9260_config = {
@@ -84,6 +86,7 @@ static struct at91_twi_pdata at91sam9260_config = {
 	.has_unre_flag = false,
 	.has_alt_cmd = false,
 	.has_hold_field = false,
+	.has_clear_cmd = false,
 };
 
 static struct at91_twi_pdata at91sam9g20_config = {
@@ -92,6 +95,7 @@ static struct at91_twi_pdata at91sam9g20_config = {
 	.has_unre_flag = false,
 	.has_alt_cmd = false,
 	.has_hold_field = false,
+	.has_clear_cmd = false,
 };
 
 static struct at91_twi_pdata at91sam9g10_config = {
@@ -100,6 +104,7 @@ static struct at91_twi_pdata at91sam9g10_config = {
 	.has_unre_flag = false,
 	.has_alt_cmd = false,
 	.has_hold_field = false,
+	.has_clear_cmd = false,
 };
 
 static const struct platform_device_id at91_twi_devtypes[] = {
@@ -130,6 +135,7 @@ static struct at91_twi_pdata at91sam9x5_config = {
 	.has_unre_flag = false,
 	.has_alt_cmd = false,
 	.has_hold_field = false,
+	.has_clear_cmd = false,
 };
 
 static struct at91_twi_pdata sama5d4_config = {
@@ -138,6 +144,7 @@ static struct at91_twi_pdata sama5d4_config = {
 	.has_unre_flag = false,
 	.has_alt_cmd = false,
 	.has_hold_field = true,
+	.has_clear_cmd = false,
 };
 
 static struct at91_twi_pdata sama5d2_config = {
@@ -146,6 +153,7 @@ static struct at91_twi_pdata sama5d2_config = {
 	.has_unre_flag = true,
 	.has_alt_cmd = true,
 	.has_hold_field = true,
+	.has_clear_cmd = true,
 };
 
 static const struct of_device_id atmel_twi_dt_ids[] = {
diff --git a/drivers/i2c/busses/i2c-at91-master.c b/drivers/i2c/busses/i2c-at91-master.c
index a3fcc35ffd3b..12d4fa946a82 100644
--- a/drivers/i2c/busses/i2c-at91-master.c
+++ b/drivers/i2c/busses/i2c-at91-master.c
@@ -440,6 +440,7 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev)
 	unsigned long time_left;
 	bool has_unre_flag = dev->pdata->has_unre_flag;
 	bool has_alt_cmd = dev->pdata->has_alt_cmd;
+	bool has_clear_cmd = dev->pdata->has_clear_cmd;
 
 	/*
 	 * WARNING: the TXCOMP bit in the Status Register is NOT a clear on
@@ -599,6 +600,27 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev)
 		at91_twi_write(dev, AT91_TWI_CR,
 			       AT91_TWI_THRCLR | AT91_TWI_LOCKCLR);
 	}
+
+	/*
+	 * After timeout, some faulty I2C slave devices might hold SCL/SDA down;
+	 * we can send a bus clear command, hoping that the pins will be
+	 * released
+	 */
+	if (has_clear_cmd &&
+	    (!(dev->transfer_status & AT91_TWI_SDA) ||
+	     !(dev->transfer_status & AT91_TWI_SCL))) {
+		dev_dbg(dev->dev,
+			"SDA/SCL are down; sending bus clear command\n");
+		if (dev->use_alt_cmd) {
+			unsigned int acr;
+
+			acr = at91_twi_read(dev, AT91_TWI_ACR);
+			acr &= ~AT91_TWI_ACR_DATAL_MASK;
+			at91_twi_write(dev, AT91_TWI_ACR, acr);
+		}
+		at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_CLEAR);
+	}
+
 	return ret;
 }
 
diff --git a/drivers/i2c/busses/i2c-at91.h b/drivers/i2c/busses/i2c-at91.h
index 499b506f6128..0827c28a84db 100644
--- a/drivers/i2c/busses/i2c-at91.h
+++ b/drivers/i2c/busses/i2c-at91.h
@@ -36,6 +36,7 @@
 #define	AT91_TWI_SVDIS		BIT(5)	/* Slave Transfer Disable */
 #define	AT91_TWI_QUICK		BIT(6)	/* SMBus quick command */
 #define	AT91_TWI_SWRST		BIT(7)	/* Software Reset */
+#define	AT91_TWI_CLEAR		BIT(15) /* Bus clear command */
 #define	AT91_TWI_ACMEN		BIT(16) /* Alternative Command Mode Enable */
 #define	AT91_TWI_ACMDIS		BIT(17) /* Alternative Command Mode Disable */
 #define	AT91_TWI_THRCLR		BIT(24) /* Transmit Holding Register Clear */
@@ -69,6 +70,8 @@
 #define	AT91_TWI_NACK		BIT(8)	/* Not Acknowledged */
 #define	AT91_TWI_EOSACC		BIT(11)	/* End Of Slave Access */
 #define	AT91_TWI_LOCK		BIT(23) /* TWI Lock due to Frame Errors */
+#define	AT91_TWI_SCL		BIT(24) /* TWI SCL status */
+#define	AT91_TWI_SDA		BIT(25) /* TWI SDA status */
 
 #define	AT91_TWI_INT_MASK \
 	(AT91_TWI_TXCOMP | AT91_TWI_RXRDY | AT91_TWI_TXRDY | AT91_TWI_NACK \
@@ -81,7 +84,8 @@
 #define	AT91_TWI_THR		0x0034	/* Transmit Holding Register */
 
 #define	AT91_TWI_ACR		0x0040	/* Alternative Command Register */
-#define	AT91_TWI_ACR_DATAL(len)	((len) & 0xff)
+#define	AT91_TWI_ACR_DATAL_MASK	GENMASK(15, 0)
+#define	AT91_TWI_ACR_DATAL(len)	((len) & AT91_TWI_ACR_DATAL_MASK)
 #define	AT91_TWI_ACR_DIR	BIT(8)
 
 #define	AT91_TWI_FMR		0x0050	/* FIFO Mode Register */
@@ -108,6 +112,7 @@ struct at91_twi_pdata {
 	bool has_unre_flag;
 	bool has_alt_cmd;
 	bool has_hold_field;
+	bool has_clear_cmd;
 	struct at_dma_slave dma_slave;
 };
 
-- 
2.23.0

[PATCH v2 2/5] dt-bindings: i2c: at91: document optional bus recovery properties

[Kamel Bouhara]

The at91 I2C controller can support bus recovery by re-assigning SCL
and SDA to gpios. Add the optional pinctrl and gpio properties to do
so.

Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
---
 Documentation/devicetree/bindings/i2c/i2c-at91.txt | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/Documentation/devicetree/bindings/i2c/i2c-at91.txt b/Documentation/devicetree/bindings/i2c/i2c-at91.txt
index b7cec17c3daf..8ea2ce5d8610 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-at91.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-at91.txt
@@ -19,8 +19,13 @@ Optional properties:
   capable I2C controllers.
 - i2c-sda-hold-time-ns: TWD hold time, only available for "atmel,sama5d4-i2c"
   and "atmel,sama5d2-i2c".
+- scl-gpios: specify the gpio related to SCL pin
+- sda-gpios: specify the gpio related to SDA pin
+- pinctrl: add extra pinctrl to configure i2c pins to gpio function for i2c
+  bus recovery, call it "gpio" state
 - Child nodes conforming to i2c bus binding
 
+
 Examples :
 
 i2c0: i2c@fff84000 {
@@ -55,6 +60,11 @@ i2c0: i2c@f8034600 {
 	clocks = <&flx0>;
 	atmel,fifo-size = <16>;
 	i2c-sda-hold-time-ns = <336>;
+	pinctrl-names = "default", "gpio";
+	pinctrl-0 = <&pinctrl_i2c0>;
+	pinctrl-1 = <&pinctrl_i2c0_gpio>;
+	sda-gpios = <&pioA 30 GPIO_ACTIVE_HIGH>;
+	scl-gpios = <&pioA 31 GPIO_ACTIVE_HIGH>;
 
 	wm8731: wm8731@1a {
 		compatible = "wm8731";
-- 
2.23.0

[PATCH v2 3/5] i2c: at91: implement i2c bus recovery

[Kamel Bouhara]

Implement i2c bus recovery when slaves devices might hold SDA low.
In this case re-assign SCL/SDA to gpios and issue 9 dummy clock pulses
until the slave release SDA.

Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
---
Changes in v2:
==============
	- Add missing call to i2c_bus_recover() when a i2c transfer
	  timeout.

 drivers/i2c/busses/i2c-at91-master.c | 64 ++++++++++++++++++++++++++++
 drivers/i2c/busses/i2c-at91.h        |  8 ++++
 2 files changed, 72 insertions(+)

diff --git a/drivers/i2c/busses/i2c-at91-master.c b/drivers/i2c/busses/i2c-at91-master.c
index 12d4fa946a82..8116f3cd373b 100644
--- a/drivers/i2c/busses/i2c-at91-master.c
+++ b/drivers/i2c/busses/i2c-at91-master.c
@@ -18,11 +18,13 @@
 #include <linux/dma-mapping.h>
 #include <linux/dmaengine.h>
 #include <linux/err.h>
+#include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/pinctrl/consumer.h>
 #include <linux/platform_device.h>
 #include <linux/platform_data/dma-atmel.h>
 #include <linux/pm_runtime.h>
@@ -555,6 +557,7 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev)
 	if (time_left == 0) {
 		dev->transfer_status |= at91_twi_read(dev, AT91_TWI_SR);
 		dev_err(dev->dev, "controller timed out\n");
+		i2c_recover_bus(&dev->adapter);
 		at91_init_twi_bus(dev);
 		ret = -ETIMEDOUT;
 		goto error;
@@ -790,6 +793,63 @@ static int at91_twi_configure_dma(struct at91_twi_dev *dev, u32 phy_addr)
 	return ret;
 }

+static void at91_prepare_twi_recovery(struct i2c_adapter *adap)
+{
+	struct at91_twi_dev *dev = i2c_get_adapdata(adap);
+
+	pinctrl_select_state(dev->pinctrl, dev->pinctrl_pins_gpio);
+}
+
+static void at91_unprepare_twi_recovery(struct i2c_adapter *adap)
+{
+	struct at91_twi_dev *dev = i2c_get_adapdata(adap);
+
+	pinctrl_select_state(dev->pinctrl, dev->pinctrl_pins_default);
+}
+
+static int at91_init_twi_recovery_info(struct platform_device *pdev,
+				       struct at91_twi_dev *dev)
+{
+	struct i2c_bus_recovery_info *rinfo = &dev->rinfo;
+
+	dev->pinctrl = devm_pinctrl_get(&pdev->dev);
+	if (!dev->pinctrl || IS_ERR(dev->pinctrl)) {
+		dev_info(dev->dev, "can't get pinctrl, bus recovery not supported\n");
+		return PTR_ERR(dev->pinctrl);
+	}
+
+	dev->pinctrl_pins_default = pinctrl_lookup_state(dev->pinctrl,
+							 PINCTRL_STATE_DEFAULT);
+	dev->pinctrl_pins_gpio = pinctrl_lookup_state(dev->pinctrl,
+						      "gpio");
+	rinfo->sda_gpiod = devm_gpiod_get(&pdev->dev, "sda", GPIOD_IN);
+	if (PTR_ERR(rinfo->sda_gpiod) == -EPROBE_DEFER)
+		return -EPROBE_DEFER;
+
+	rinfo->scl_gpiod = devm_gpiod_get(&pdev->dev, "scl",
+					  GPIOD_OUT_HIGH_OPEN_DRAIN);
+	if (PTR_ERR(rinfo->scl_gpiod) == -EPROBE_DEFER)
+		return -EPROBE_DEFER;
+
+	if (IS_ERR(rinfo->sda_gpiod) ||
+	    IS_ERR(rinfo->scl_gpiod) ||
+	    IS_ERR(dev->pinctrl_pins_default) ||
+	    IS_ERR(dev->pinctrl_pins_gpio)) {
+		dev_info(&pdev->dev, "recovery information incomplete\n");
+		return -EINVAL;
+	}
+
+	dev_info(&pdev->dev, "using scl%s for recovery\n",
+		 rinfo->sda_gpiod ? ",sda" : "");
+
+	rinfo->prepare_recovery = at91_prepare_twi_recovery;
+	rinfo->unprepare_recovery = at91_unprepare_twi_recovery;
+	rinfo->recover_bus = i2c_generic_scl_recovery;
+	dev->adapter.bus_recovery_info = rinfo;
+
+	return 0;
+}
+
 int at91_twi_probe_master(struct platform_device *pdev,
 			  u32 phy_addr, struct at91_twi_dev *dev)
 {
@@ -817,6 +877,10 @@ int at91_twi_probe_master(struct platform_device *pdev,

 	at91_calc_twi_clock(dev);

+	rc = at91_init_twi_recovery_info(pdev, dev);
+	if (rc == -EPROBE_DEFER)
+		return rc;
+
 	dev->adapter.algo = &at91_twi_algorithm;
 	dev->adapter.quirks = &at91_twi_quirks;

diff --git a/drivers/i2c/busses/i2c-at91.h b/drivers/i2c/busses/i2c-at91.h
index 0827c28a84db..167be7aa8e67 100644
--- a/drivers/i2c/busses/i2c-at91.h
+++ b/drivers/i2c/busses/i2c-at91.h
@@ -146,6 +146,10 @@ struct at91_twi_dev {
 	u32 fifo_size;
 	struct at91_twi_dma dma;
 	bool slave_detected;
+	struct i2c_bus_recovery_info rinfo;
+	struct pinctrl *pinctrl;
+	struct pinctrl_state *pinctrl_pins_default;
+	struct pinctrl_state *pinctrl_pins_gpio;
 #ifdef CONFIG_I2C_AT91_SLAVE_EXPERIMENTAL
 	unsigned smr;
 	struct i2c_client *slave;
@@ -163,6 +167,10 @@ void at91_init_twi_bus_master(struct at91_twi_dev *dev);
 int at91_twi_probe_master(struct platform_device *pdev, u32 phy_addr,
 			  struct at91_twi_dev *dev);

+void at91_twi_prepare_recovery(struct i2c_adapter *adap);
+void at91_twi_unprepare_recovery(struct i2c_adapter *adap);
+void at91_twi_init_recovery_info(struct at91_twi_dev *dev);
+
 #ifdef CONFIG_I2C_AT91_SLAVE_EXPERIMENTAL
 void at91_init_twi_bus_slave(struct at91_twi_dev *dev);
 int at91_twi_probe_slave(struct platform_device *pdev, u32 phy_addr,
--
2.23.0

[PATCH v2 4/5] ARM: at91/dt: sama5d3: add i2c gpio pinctrl

[Kamel Bouhara]

Add the i2c gpio pinctrls to support the i2c bus recovery

Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
---
 arch/arm/boot/dts/sama5d3.dtsi | 33 ++++++++++++++++++++++++++++++---
 1 file changed, 30 insertions(+), 3 deletions(-)

diff --git a/arch/arm/boot/dts/sama5d3.dtsi b/arch/arm/boot/dts/sama5d3.dtsi
index f770aace0efd..faf8907d8d7d 100644
--- a/arch/arm/boot/dts/sama5d3.dtsi
+++ b/arch/arm/boot/dts/sama5d3.dtsi
@@ -159,8 +159,11 @@
 				dmas = <&dma0 2 AT91_DMA_CFG_PER_ID(7)>,
 				       <&dma0 2 AT91_DMA_CFG_PER_ID(8)>;
 				dma-names = "tx", "rx";
-				pinctrl-names = "default";
+				pinctrl-names = "default", "gpio";
 				pinctrl-0 = <&pinctrl_i2c0>;
+				pinctrl-1 = <&pinctrl_i2c0_gpio>;
+				sda-gpios = <&pioA 30 GPIO_ACTIVE_HIGH>;
+				scl-gpios = <&pioA 31 GPIO_ACTIVE_HIGH>;
 				#address-cells = <1>;
 				#size-cells = <0>;
 				clocks = <&twi0_clk>;
@@ -174,8 +177,11 @@
 				dmas = <&dma0 2 AT91_DMA_CFG_PER_ID(9)>,
 				       <&dma0 2 AT91_DMA_CFG_PER_ID(10)>;
 				dma-names = "tx", "rx";
-				pinctrl-names = "default";
+				pinctrl-names = "default", "gpio";
 				pinctrl-0 = <&pinctrl_i2c1>;
+				pinctrl-1 = <&pinctrl_i2c1_gpio>;
+				sda-gpios = <&pioC 26 GPIO_ACTIVE_HIGH>;
+				scl-gpios = <&pioC 27 GPIO_ACTIVE_HIGH>;
 				#address-cells = <1>;
 				#size-cells = <0>;
 				clocks = <&twi1_clk>;
@@ -357,8 +363,11 @@
 				dmas = <&dma1 2 AT91_DMA_CFG_PER_ID(11)>,
 				       <&dma1 2 AT91_DMA_CFG_PER_ID(12)>;
 				dma-names = "tx", "rx";
-				pinctrl-names = "default";
+				pinctrl-names = "default", "gpio";
 				pinctrl-0 = <&pinctrl_i2c2>;
+				pinctrl-1 = <&pinctrl_i2c2_gpio>;
+				sda-gpios = <&pioA 18 GPIO_ACTIVE_HIGH>;
+				scl-gpios = <&pioA 19 GPIO_ACTIVE_HIGH>;
 				#address-cells = <1>;
 				#size-cells = <0>;
 				clocks = <&twi2_clk>;
@@ -639,6 +648,12 @@
 							<AT91_PIOA 30 AT91_PERIPH_A AT91_PINCTRL_NONE	/* PA30 periph A TWD0 pin, conflicts with URXD1, ISI_VSYNC */
 							 AT91_PIOA 31 AT91_PERIPH_A AT91_PINCTRL_NONE>;	/* PA31 periph A TWCK0 pin, conflicts with UTXD1, ISI_HSYNC */
 					};
+
+					pinctrl_i2c0_gpio: i2c0-gpio {
+						atmel,pins =
+							<AT91_PIOA 30 AT91_PERIPH_GPIO AT91_PINCTRL_PULL_UP
+							 AT91_PIOA 31 AT91_PERIPH_GPIO AT91_PINCTRL_PULL_UP>;
+					};
 				};
 
 				i2c1 {
@@ -647,6 +662,12 @@
 							<AT91_PIOC 26 AT91_PERIPH_B AT91_PINCTRL_NONE	/* PC26 periph B TWD1 pin, conflicts with SPI1_NPCS1, ISI_D11 */
 							 AT91_PIOC 27 AT91_PERIPH_B AT91_PINCTRL_NONE>;	/* PC27 periph B TWCK1 pin, conflicts with SPI1_NPCS2, ISI_D10 */
 					};
+
+					pinctrl_i2c1_gpio: i2c1-gpio {
+						atmel,pins =
+							<AT91_PIOC 26 AT91_PERIPH_GPIO AT91_PINCTRL_PULL_UP
+							 AT91_PIOC 27 AT91_PERIPH_GPIO AT91_PINCTRL_PULL_UP>;
+					};
 				};
 
 				i2c2 {
@@ -655,6 +676,12 @@
 							<AT91_PIOA 18 AT91_PERIPH_B AT91_PINCTRL_NONE	/* TWD2 pin, conflicts with LCDDAT18, ISI_D2 */
 							 AT91_PIOA 19 AT91_PERIPH_B AT91_PINCTRL_NONE>; /* TWCK2 pin, conflicts with LCDDAT19, ISI_D3 */
 					};
+
+					pinctrl_i2c2_gpio: i2c2-gpio {
+						atmel,pins =
+							<AT91_PIOA 18 AT91_PERIPH_GPIO AT91_PINCTRL_PULL_UP
+							 AT91_PIOA 19 AT91_PERIPH_GPIO AT91_PINCTRL_PULL_UP>;
+					};
 				};
 
 				isi {
-- 
2.23.0

[PATCH v2 5/5] ARM: at91/dt: sama5d4: add i2c gpio pinctrl

[Kamel Bouhara]

Add the i2c gpio pinctrls so the i2c bus recovery option can be enabled

Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
---
 arch/arm/boot/dts/sama5d4.dtsi | 33 ++++++++++++++++++++++++++++++---
 1 file changed, 30 insertions(+), 3 deletions(-)

diff --git a/arch/arm/boot/dts/sama5d4.dtsi b/arch/arm/boot/dts/sama5d4.dtsi
index 6ab27a7b388d..34351baab985 100644
--- a/arch/arm/boot/dts/sama5d4.dtsi
+++ b/arch/arm/boot/dts/sama5d4.dtsi
@@ -458,8 +458,11 @@
 					(AT91_XDMAC_DT_MEM_IF(0) | AT91_XDMAC_DT_PER_IF(1)
 					| AT91_XDMAC_DT_PERID(3))>;
 				dma-names = "tx", "rx";
-				pinctrl-names = "default";
+				pinctrl-names = "default", "gpio";
 				pinctrl-0 = <&pinctrl_i2c0>;
+				pinctrl-1 = <&pinctrl_i2c0_gpio>;
+				sda-gpios = <&pioA 30 GPIO_ACTIVE_HIGH>;
+				scl-gpios = <&pioA 31 GPIO_ACTIVE_HIGH>;
 				#address-cells = <1>;
 				#size-cells = <0>;
 				clocks = <&pmc PMC_TYPE_PERIPHERAL 32>;
@@ -477,8 +480,11 @@
 					(AT91_XDMAC_DT_MEM_IF(0) | AT91_XDMAC_DT_PER_IF(1)
 					| AT91_XDMAC_DT_PERID(5))>;
 				dma-names = "tx", "rx";
-				pinctrl-names = "default";
+				pinctrl-names = "default", "gpio";
 				pinctrl-0 = <&pinctrl_i2c1>;
+				pinctrl-1 = <&pinctrl_i2c1_gpio>;
+				sda-gpios = <&pioE 29 GPIO_ACTIVE_HIGH>;
+				scl-gpios = <&pioE 30 GPIO_ACTIVE_HIGH>;
 				#address-cells = <1>;
 				#size-cells = <0>;
 				clocks = <&pmc PMC_TYPE_PERIPHERAL 33>;
@@ -519,8 +525,11 @@
 					(AT91_XDMAC_DT_MEM_IF(0) | AT91_XDMAC_DT_PER_IF(1)
 					| AT91_XDMAC_DT_PERID(7))>;
 				dma-names = "tx", "rx";
-				pinctrl-names = "default";
+				pinctrl-names = "default", "gpio";
 				pinctrl-0 = <&pinctrl_i2c2>;
+				pinctrl-1 = <&pinctrl_i2c2_gpio>;
+				sda-gpios = <&pioB 29 GPIO_ACTIVE_HIGH>;
+				scl-gpios = <&pioB 30 GPIO_ACTIVE_HIGH>;
 				#address-cells = <1>;
 				#size-cells = <0>;
 				clocks = <&pmc PMC_TYPE_PERIPHERAL 34>;
@@ -1122,6 +1131,12 @@
 							<AT91_PIOA 30 AT91_PERIPH_A AT91_PINCTRL_NONE
 							 AT91_PIOA 31 AT91_PERIPH_A AT91_PINCTRL_NONE>;
 					};
+
+					pinctrl_i2c0_gpio: i2c0-gpio {
+						atmel,pins =
+							<AT91_PIOA 30 AT91_PERIPH_GPIO AT91_PINCTRL_PULL_UP
+							 AT91_PIOA 31 AT91_PERIPH_GPIO AT91_PINCTRL_PULL_UP>;
+					};
 				};
 
 				i2c1 {
@@ -1130,6 +1145,12 @@
 							<AT91_PIOE 29 AT91_PERIPH_C AT91_PINCTRL_NONE	/* TWD1, conflicts with UART0 RX and DIBP */
 							 AT91_PIOE 30 AT91_PERIPH_C AT91_PINCTRL_NONE>;	/* TWCK1, conflicts with UART0 TX and DIBN */
 					};
+
+					pinctrl_i2c1_gpio: i2c1-gpio {
+						atmel,pins =
+							<AT91_PIOE 29 AT91_PERIPH_GPIO AT91_PINCTRL_PULL_UP
+							 AT91_PIOE 30 AT91_PERIPH_GPIO AT91_PINCTRL_PULL_UP>;
+					};
 				};
 
 				i2c2 {
@@ -1138,6 +1159,12 @@
 							<AT91_PIOB 29 AT91_PERIPH_A AT91_PINCTRL_NONE	/* TWD2, conflicts with RD0 and PWML1 */
 							 AT91_PIOB 30 AT91_PERIPH_A AT91_PINCTRL_NONE>; /* TWCK2, conflicts with RF0 */
 					};
+
+					pinctrl_i2c2_gpio: i2c2-gpio {
+						atmel,pins =
+							<AT91_PIOB 29 AT91_PERIPH_GPIO AT91_PINCTRL_PULL_UP
+							 AT91_PIOB 30 AT91_PERIPH_GPIO AT91_PINCTRL_PULL_UP>;
+					};
 				};
 
 				isi {
-- 
2.23.0

Re: [PATCH v2 2/5] dt-bindings: i2c: at91: document optional bus recovery properties

[Rob Herring]

On Thu, 24 Oct 2019 22:12:59 +0200, Kamel Bouhara wrote:
> The at91 I2C controller can support bus recovery by re-assigning SCL
> and SDA to gpios. Add the optional pinctrl and gpio properties to do
> so.
> 
> Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
> ---
>  Documentation/devicetree/bindings/i2c/i2c-at91.txt | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 

Reviewed-by: Rob Herring <robh@kernel.org>