[PATCH v3 0/6] i2c bus recovery for Microchip SoCs

[PATCH v3 0/6] i2c bus recovery for Microchip SoCs

[Codrin Ciubotariu]

This patch series introduce the i2c bus recovery mechanism
for the Microchip SoCs. Some SoCs have hardware support for
recovery, while for those who don't the i2c-gpio bus recovery
mechanism is used. Updated the corresponding dts to add i2c
gpio pinctrl. The bus recovery is configured for the sama5d2/3/4
xplained and sama5d27 som1 EK boards in dts.

Changes in v3:
 - addressed list comments:
  - removed pull-ups from gpios;
  - removed unused headers from i2c-at91.h;
  - fixed commit message and subject on patch 3/6;
  - added received tags;
 - rebased on top of i2c/for-next;

Changes in v2:
 - integrated the HW CLEAR command patch;
 - call i2c_recover_bus() after an error occurs, if SDA is down;
 - added i2c gpio pinctrl in sama5d2 xplained and sama5d27 som1 EK
   boards;

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

Kamel Bouhara (5):
  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
  ARM: at91/dt: sama5d2: add i2c gpio pinctrl

 .../devicetree/bindings/i2c/i2c-at91.txt      |  10 ++
 arch/arm/boot/dts/at91-sama5d2_ptc_ek.dts     |  33 +++++-
 arch/arm/boot/dts/at91-sama5d2_xplained.dts   |  33 +++++-
 arch/arm/boot/dts/sama5d3.dtsi                |  33 +++++-
 arch/arm/boot/dts/sama5d4.dtsi                |  33 +++++-
 drivers/i2c/busses/i2c-at91-core.c            |   2 +
 drivers/i2c/busses/i2c-at91-master.c          | 100 ++++++++++++++++++
 drivers/i2c/busses/i2c-at91.h                 |  11 +-
 8 files changed, 242 insertions(+), 13 deletions(-)

-- 
2.20.1

[PATCH v3 1/6] dt-bindings: i2c: at91: document optional bus recovery properties

[Codrin Ciubotariu]

From: Kamel Bouhara <kamel.bouhara@bootlin.com>

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>
[codrin.ciubotariu@microchip.com: rebased]
Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Reviewed-by: Rob Herring <robh@kernel.org>
---

Changes in v3:
 - rebased;
 - added Reviewed-by tag from Rob;

Changes in v2:
 - none;

 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 d4bad86107b8..96c914e048f5 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-at91.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-at91.txt
@@ -28,8 +28,13 @@ Optional properties:
 	"atmel,sama5d4-i2c",
 	"atmel,sama5d2-i2c",
 	"microchip,sam9x60-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 {
@@ -64,6 +69,11 @@ 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";
-- 
2.20.1

[PATCH v3 2/6] i2c: at91: implement i2c bus recovery

[Codrin Ciubotariu]

From: Kamel Bouhara <kamel.bouhara@bootlin.com>

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>
Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
---

Changes in v3:
 - removed unnecessary condition from info print;
 - removed unneded declarations;

Changes in v2:
 - called i2c_recover_bus() after an error occurs, if SDA is down;
 - release gpios if recovery information is incomplete;

 drivers/i2c/busses/i2c-at91-master.c | 78 ++++++++++++++++++++++++++++
 drivers/i2c/busses/i2c-at91.h        |  4 ++
 2 files changed, 82 insertions(+)

diff --git a/drivers/i2c/busses/i2c-at91-master.c b/drivers/i2c/busses/i2c-at91-master.c
index 7a862e00b475..0aba51a7df32 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>
@@ -478,6 +480,7 @@ 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;
+	struct i2c_bus_recovery_info *rinfo = &dev->rinfo;
 
 	/*
 	 * WARNING: the TXCOMP bit in the Status Register is NOT a clear on
@@ -637,6 +640,13 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev)
 		at91_twi_write(dev, AT91_TWI_CR,
 			       AT91_TWI_THRCLR | AT91_TWI_LOCKCLR);
 	}
+
+	if (rinfo->get_sda && !(rinfo->get_sda(&dev->adapter))) {
+		dev_dbg(dev->dev,
+			"SDA is down; clear bus using gpio\n");
+		i2c_recover_bus(&dev->adapter);
+	}
+
 	return ret;
 }
 
@@ -806,6 +816,70 @@ 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");
+		if (!IS_ERR(rinfo->sda_gpiod)) {
+			gpiod_put(rinfo->sda_gpiod);
+			rinfo->sda_gpiod = NULL;
+		}
+		if (!IS_ERR(rinfo->scl_gpiod)) {
+			gpiod_put(rinfo->scl_gpiod);
+			rinfo->scl_gpiod = NULL;
+		}
+		return -EINVAL;
+	}
+
+	dev_info(&pdev->dev, "using scl, sda for recovery\n");
+
+	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)
 {
@@ -838,6 +912,10 @@ int at91_twi_probe_master(struct platform_device *pdev,
 						     "i2c-analog-filter");
 	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 977a67bc0f88..f57a6cab96b4 100644
--- a/drivers/i2c/busses/i2c-at91.h
+++ b/drivers/i2c/busses/i2c-at91.h
@@ -151,6 +151,10 @@ 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;
-- 
2.20.1

[PATCH v3 3/6] i2c: at91: Send bus clear command if SDA is down

[Codrin Ciubotariu]

After a transfer timeout, some faulty I2C slave devices might hold down
the SDA pin. We can generate a bus clear command, hoping that the slave
might release the pins.
If the CLEAR command is not supported, we will use gpio recovery, if
available, to reset the bus.

Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
---

Changes in v3:
 - rebased on top of i2c/for-next;
  - remove unnecessary initializations with false;
 - replaced SCL with SDA in title and commit message;
 - updated commit message;

Changes in v2:
 - use CLEAR command only if SDA is down; update patch subject to
   reflect this;
 - CLEAR command is no longer used for sama5d2, only sam9x60;

 drivers/i2c/busses/i2c-at91-core.c   |  2 ++
 drivers/i2c/busses/i2c-at91-master.c | 32 +++++++++++++++++++++++-----
 drivers/i2c/busses/i2c-at91.h        |  7 +++++-
 3 files changed, 35 insertions(+), 6 deletions(-)

diff --git a/drivers/i2c/busses/i2c-at91-core.c b/drivers/i2c/busses/i2c-at91-core.c
index 3da1a8acecb5..e14edd236108 100644
--- a/drivers/i2c/busses/i2c-at91-core.c
+++ b/drivers/i2c/busses/i2c-at91-core.c
@@ -131,6 +131,7 @@ static struct at91_twi_pdata sama5d2_config = {
 	.has_dig_filtr = true,
 	.has_adv_dig_filtr = true,
 	.has_ana_filtr = true,
+	.has_clear_cmd = false,	/* due to errata, CLEAR cmd is not working */
 };
 
 static struct at91_twi_pdata sam9x60_config = {
@@ -142,6 +143,7 @@ static struct at91_twi_pdata sam9x60_config = {
 	.has_dig_filtr = true,
 	.has_adv_dig_filtr = true,
 	.has_ana_filtr = 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 0aba51a7df32..bcc05a8fe826 100644
--- a/drivers/i2c/busses/i2c-at91-master.c
+++ b/drivers/i2c/busses/i2c-at91-master.c
@@ -480,7 +480,7 @@ 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;
-	struct i2c_bus_recovery_info *rinfo = &dev->rinfo;
+	bool has_clear_cmd = dev->pdata->has_clear_cmd;
 
 	/*
 	 * WARNING: the TXCOMP bit in the Status Register is NOT a clear on
@@ -641,10 +641,32 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev)
 			       AT91_TWI_THRCLR | AT91_TWI_LOCKCLR);
 	}
 
-	if (rinfo->get_sda && !(rinfo->get_sda(&dev->adapter))) {
-		dev_dbg(dev->dev,
-			"SDA is down; clear bus using gpio\n");
-		i2c_recover_bus(&dev->adapter);
+	/*
+	 * some faulty I2C slave devices might hold SDA down;
+	 * we can send a bus clear command, hoping that the pins will be
+	 * released
+	 */
+	if (has_clear_cmd) {
+		if (!(dev->transfer_status & AT91_TWI_SDA)) {
+			dev_dbg(dev->dev,
+				"SDA is 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);
+		}
+	} else {
+		struct i2c_bus_recovery_info *rinfo = &dev->rinfo;
+
+		if (rinfo->get_sda && !(rinfo->get_sda(&dev->adapter))) {
+			dev_dbg(dev->dev,
+				"SDA is down; clear bus using gpio\n");
+			i2c_recover_bus(&dev->adapter);
+		}
 	}
 
 	return ret;
diff --git a/drivers/i2c/busses/i2c-at91.h b/drivers/i2c/busses/i2c-at91.h
index f57a6cab96b4..7e7b4955ca7f 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_FILTR		0x0044
@@ -118,6 +122,7 @@ struct at91_twi_pdata {
 	bool has_dig_filtr;
 	bool has_adv_dig_filtr;
 	bool has_ana_filtr;
+	bool has_clear_cmd;
 	struct at_dma_slave dma_slave;
 };
 
-- 
2.20.1

[PATCH v3 4/6] ARM: at91/dt: sama5d3: add i2c gpio pinctrl

[Codrin Ciubotariu]

From: Kamel Bouhara <kamel.bouhara@bootlin.com>

Add the i2c gpio pinctrls to support the i2c bus recovery

Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
[codrin.ciubotariu@microchip.com: removed gpio pull-ups]
Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
---

Changes in v3:
 - removed gpio pull-ups;

Changes in v2:
  - none;

 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..1cea2137decf 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_NONE
+							 AT91_PIOA 31 AT91_PERIPH_GPIO AT91_PINCTRL_NONE>;
+					};
 				};
 
 				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_NONE
+							 AT91_PIOC 27 AT91_PERIPH_GPIO AT91_PINCTRL_NONE>;
+					};
 				};
 
 				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_NONE
+							 AT91_PIOA 19 AT91_PERIPH_GPIO AT91_PINCTRL_NONE>;
+					};
 				};
 
 				isi {
-- 
2.20.1

[PATCH v3 5/6] ARM: at91/dt: sama5d4: add i2c gpio pinctrl

[Codrin Ciubotariu]

From: Kamel Bouhara <kamel.bouhara@bootlin.com>

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

Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
[codrin.ciubotariu@microchip.com: removed gpio pull-ups]
Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
---

Changes in v3:
 - removed gpio pull-ups;

Changes in v2:
 - none;

 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..26ce868096c2 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_NONE
+							 AT91_PIOA 31 AT91_PERIPH_GPIO AT91_PINCTRL_NONE>;
+					};
 				};
 
 				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_NONE
+							 AT91_PIOE 30 AT91_PERIPH_GPIO AT91_PINCTRL_NONE>;
+					};
 				};
 
 				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_NONE
+							 AT91_PIOB 30 AT91_PERIPH_GPIO AT91_PINCTRL_NONE>;
+					};
 				};
 
 				isi {
-- 
2.20.1

[PATCH v3 6/6] ARM: at91/dt: sama5d2: add i2c gpio pinctrl

[Codrin Ciubotariu]

From: Kamel Bouhara <kamel.bouhara@bootlin.com>

Add the i2c gpio pinctrls to support the i2c bus recovery

Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
[codrin.ciubotariu@microchip.com: removed gpio pull-ups]
Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
---

Changes in v3:
 - removed gpio pull-ups;

Changes in v2:
 - new patch;

 arch/arm/boot/dts/at91-sama5d2_ptc_ek.dts   | 33 +++++++++++++++++++--
 arch/arm/boot/dts/at91-sama5d2_xplained.dts | 33 +++++++++++++++++++--
 2 files changed, 60 insertions(+), 6 deletions(-)

diff --git a/arch/arm/boot/dts/at91-sama5d2_ptc_ek.dts b/arch/arm/boot/dts/at91-sama5d2_ptc_ek.dts
index ba7f3e646c26..1c24ac8019ba 100644
--- a/arch/arm/boot/dts/at91-sama5d2_ptc_ek.dts
+++ b/arch/arm/boot/dts/at91-sama5d2_ptc_ek.dts
@@ -180,8 +180,11 @@
 
 			i2c0: i2c@f8028000 {
 				dmas = <0>, <0>;
-				pinctrl-names = "default";
+				pinctrl-names = "default", "gpio";
 				pinctrl-0 = <&pinctrl_i2c0_default>;
+				pinctrl-1 = <&pinctrl_i2c0_gpio>;
+				sda-gpios = <&pioA PIN_PD21 GPIO_ACTIVE_HIGH>;
+				scl-gpios = <&pioA PIN_PD22 GPIO_ACTIVE_HIGH>;
 				status = "okay";
 			};
 
@@ -198,8 +201,11 @@
 					#address-cells = <1>;
 					#size-cells = <0>;
 					clocks = <&pmc PMC_TYPE_PERIPHERAL 19>;
-					pinctrl-names = "default";
+					pinctrl-names = "default", "gpio";
 					pinctrl-0 = <&pinctrl_flx0_default>;
+					pinctrl-1 = <&pinctrl_flx0_gpio>;
+					sda-gpios = <&pioA PIN_PB28 GPIO_ACTIVE_HIGH>;
+					scl-gpios = <&pioA PIN_PB29 GPIO_ACTIVE_HIGH>;
 					atmel,fifo-size = <16>;
 					status = "okay";
 				};
@@ -226,8 +232,11 @@
 
 			i2c1: i2c@fc028000 {
 				dmas = <0>, <0>;
-				pinctrl-names = "default";
+				pinctrl-names = "default", "gpio";
 				pinctrl-0 = <&pinctrl_i2c1_default>;
+				pinctrl-1 = <&pinctrl_i2c1_gpio>;
+				sda-gpios = <&pioA PIN_PC6 GPIO_ACTIVE_HIGH>;
+				scl-gpios = <&pioA PIN_PC7 GPIO_ACTIVE_HIGH>;
 				status = "okay";
 
 				at24@50 {
@@ -244,18 +253,36 @@
 					bias-disable;
 				};
 
+				pinctrl_flx0_gpio: flx0_gpio {
+					pinmux = <PIN_PB28__GPIO>,
+						 <PIN_PB29__GPIO>;
+					bias-disable;
+				};
+
 				pinctrl_i2c0_default: i2c0_default {
 					pinmux = <PIN_PD21__TWD0>,
 						 <PIN_PD22__TWCK0>;
 					bias-disable;
 				};
 
+				pinctrl_i2c0_gpio: i2c0_gpio {
+					pinmux = <PIN_PD21__GPIO>,
+						 <PIN_PD22__GPIO>;
+					bias-disable;
+				};
+
 				pinctrl_i2c1_default: i2c1_default {
 					pinmux = <PIN_PC6__TWD1>,
 						 <PIN_PC7__TWCK1>;
 					bias-disable;
 				};
 
+				pinctrl_i2c1_gpio: i2c1_gpio {
+					pinmux = <PIN_PC6__GPIO>,
+						 <PIN_PC7__GPIO>;
+					bias-disable;
+				};
+
 				pinctrl_key_gpio_default: key_gpio_default {
 					pinmux = <PIN_PA10__GPIO>;
 					bias-pull-up;
diff --git a/arch/arm/boot/dts/at91-sama5d2_xplained.dts b/arch/arm/boot/dts/at91-sama5d2_xplained.dts
index 9d0a7fbea725..055ee53e4773 100644
--- a/arch/arm/boot/dts/at91-sama5d2_xplained.dts
+++ b/arch/arm/boot/dts/at91-sama5d2_xplained.dts
@@ -129,8 +129,11 @@
 
 			i2c0: i2c@f8028000 {
 				dmas = <0>, <0>;
-				pinctrl-names = "default";
+				pinctrl-names = "default", "gpio";
 				pinctrl-0 = <&pinctrl_i2c0_default>;
+				pinctrl-1 = <&pinctrl_i2c0_gpio>;
+				sda-gpios = <&pioA PIN_PD21 GPIO_ACTIVE_HIGH>;
+				scl-gpios = <&pioA PIN_PD22 GPIO_ACTIVE_HIGH>;
 				i2c-sda-hold-time-ns = <350>;
 				status = "okay";
 
@@ -331,8 +334,11 @@
 					#address-cells = <1>;
 					#size-cells = <0>;
 					clocks = <&pmc PMC_TYPE_PERIPHERAL 23>;
-					pinctrl-names = "default";
+					pinctrl-names = "default", "gpio";
 					pinctrl-0 = <&pinctrl_flx4_default>;
+					pinctrl-1 = <&pinctrl_flx4_gpio>;
+					sda-gpios = <&pioA PIN_PD12 GPIO_ACTIVE_HIGH>;
+					scl-gpios = <&pioA PIN_PD13 GPIO_ACTIVE_HIGH>;
 					atmel,fifo-size = <16>;
 					i2c-analog-filter;
 					i2c-digital-filter;
@@ -343,11 +349,14 @@
 
 			i2c1: i2c@fc028000 {
 				dmas = <0>, <0>;
-				pinctrl-names = "default";
+				pinctrl-names = "default", "gpio";
 				pinctrl-0 = <&pinctrl_i2c1_default>;
 				i2c-analog-filter;
 				i2c-digital-filter;
 				i2c-digital-filter-width-ns = <35>;
+				pinctrl-1 = <&pinctrl_i2c1_gpio>;
+				sda-gpios = <&pioA PIN_PD4 GPIO_ACTIVE_HIGH>;
+				scl-gpios = <&pioA PIN_PD5 GPIO_ACTIVE_HIGH>;
 				status = "okay";
 
 				at24@54 {
@@ -441,18 +450,36 @@
 					bias-disable;
 				};
 
+				pinctrl_flx4_gpio: flx4_gpio {
+					pinmux = <PIN_PD12__GPIO>,
+						 <PIN_PD13__GPIO>;
+					bias-disable;
+				};
+
 				pinctrl_i2c0_default: i2c0_default {
 					pinmux = <PIN_PD21__TWD0>,
 						 <PIN_PD22__TWCK0>;
 					bias-disable;
 				};
 
+				pinctrl_i2c0_gpio: i2c0_gpio {
+					pinmux = <PIN_PD21__GPIO>,
+						 <PIN_PD22__GPIO>;
+					bias-disable;
+				};
+
 				pinctrl_i2c1_default: i2c1_default {
 					pinmux = <PIN_PD4__TWD1>,
 						 <PIN_PD5__TWCK1>;
 					bias-disable;
 				};
 
+				pinctrl_i2c1_gpio: i2c1_gpio {
+					pinmux = <PIN_PD4__GPIO>,
+						 <PIN_PD5__GPIO>;
+					bias-disable;
+				};
+
 				pinctrl_i2s0_default: i2s0_default {
 					pinmux = <PIN_PC1__I2SC0_CK>,
 						 <PIN_PC2__I2SC0_MCK>,
-- 
2.20.1

Re: [PATCH v3 1/6] dt-bindings: i2c: at91: document optional bus recovery properties

[Ludovic Desroches]

On Wed, Jan 15, 2020 at 01:54:17PM +0200, Codrin Ciubotariu wrote:
> From: Kamel Bouhara <kamel.bouhara@bootlin.com>
> 
> 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>
> [codrin.ciubotariu@microchip.com: rebased]
> Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
> Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>

> ---
> 
> Changes in v3:
>  - rebased;
>  - added Reviewed-by tag from Rob;
> 
> Changes in v2:
>  - none;
> 
>  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 d4bad86107b8..96c914e048f5 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c-at91.txt
> +++ b/Documentation/devicetree/bindings/i2c/i2c-at91.txt
> @@ -28,8 +28,13 @@ Optional properties:
>  	"atmel,sama5d4-i2c",
>  	"atmel,sama5d2-i2c",
>  	"microchip,sam9x60-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 {
> @@ -64,6 +69,11 @@ 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";
> -- 
> 2.20.1
> 

Re: [PATCH v3 2/6] i2c: at91: implement i2c bus recovery

[Ludovic Desroches]

On Wed, Jan 15, 2020 at 01:54:18PM +0200, Codrin Ciubotariu wrote:
> From: Kamel Bouhara <kamel.bouhara@bootlin.com>
> 
> 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>
> Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>

> ---
> 
> Changes in v3:
>  - removed unnecessary condition from info print;
>  - removed unneded declarations;
> 
> Changes in v2:
>  - called i2c_recover_bus() after an error occurs, if SDA is down;
>  - release gpios if recovery information is incomplete;
> 
>  drivers/i2c/busses/i2c-at91-master.c | 78 ++++++++++++++++++++++++++++
>  drivers/i2c/busses/i2c-at91.h        |  4 ++
>  2 files changed, 82 insertions(+)
> 
> diff --git a/drivers/i2c/busses/i2c-at91-master.c b/drivers/i2c/busses/i2c-at91-master.c
> index 7a862e00b475..0aba51a7df32 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>
> @@ -478,6 +480,7 @@ 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;
> +	struct i2c_bus_recovery_info *rinfo = &dev->rinfo;
>  
>  	/*
>  	 * WARNING: the TXCOMP bit in the Status Register is NOT a clear on
> @@ -637,6 +640,13 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev)
>  		at91_twi_write(dev, AT91_TWI_CR,
>  			       AT91_TWI_THRCLR | AT91_TWI_LOCKCLR);
>  	}
> +
> +	if (rinfo->get_sda && !(rinfo->get_sda(&dev->adapter))) {
> +		dev_dbg(dev->dev,
> +			"SDA is down; clear bus using gpio\n");
> +		i2c_recover_bus(&dev->adapter);
> +	}
> +
>  	return ret;
>  }
>  
> @@ -806,6 +816,70 @@ 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");
> +		if (!IS_ERR(rinfo->sda_gpiod)) {
> +			gpiod_put(rinfo->sda_gpiod);
> +			rinfo->sda_gpiod = NULL;
> +		}
> +		if (!IS_ERR(rinfo->scl_gpiod)) {
> +			gpiod_put(rinfo->scl_gpiod);
> +			rinfo->scl_gpiod = NULL;
> +		}
> +		return -EINVAL;
> +	}
> +
> +	dev_info(&pdev->dev, "using scl, sda for recovery\n");
> +
> +	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)
>  {
> @@ -838,6 +912,10 @@ int at91_twi_probe_master(struct platform_device *pdev,
>  						     "i2c-analog-filter");
>  	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 977a67bc0f88..f57a6cab96b4 100644
> --- a/drivers/i2c/busses/i2c-at91.h
> +++ b/drivers/i2c/busses/i2c-at91.h
> @@ -151,6 +151,10 @@ 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;
> -- 
> 2.20.1
> 

Re: [PATCH v3 3/6] i2c: at91: Send bus clear command if SDA is down

[Ludovic Desroches]

On Wed, Jan 15, 2020 at 01:54:19PM +0200, Codrin Ciubotariu wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> After a transfer timeout, some faulty I2C slave devices might hold down
> the SDA pin. We can generate a bus clear command, hoping that the slave
> might release the pins.
> If the CLEAR command is not supported, we will use gpio recovery, if
> available, to reset the bus.
> 
> Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>

I still have issue to apply it even if the context seems correct.
Sometimes git am is picky... so

Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>

> ---
> 
> Changes in v3:
>  - rebased on top of i2c/for-next;
>   - remove unnecessary initializations with false;
>  - replaced SCL with SDA in title and commit message;
>  - updated commit message;
> 
> Changes in v2:
>  - use CLEAR command only if SDA is down; update patch subject to
>    reflect this;
>  - CLEAR command is no longer used for sama5d2, only sam9x60;
> 
>  drivers/i2c/busses/i2c-at91-core.c   |  2 ++
>  drivers/i2c/busses/i2c-at91-master.c | 32 +++++++++++++++++++++++-----
>  drivers/i2c/busses/i2c-at91.h        |  7 +++++-
>  3 files changed, 35 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-at91-core.c b/drivers/i2c/busses/i2c-at91-core.c
> index 3da1a8acecb5..e14edd236108 100644
> --- a/drivers/i2c/busses/i2c-at91-core.c
> +++ b/drivers/i2c/busses/i2c-at91-core.c
> @@ -131,6 +131,7 @@ static struct at91_twi_pdata sama5d2_config = {
>         .has_dig_filtr = true,
>         .has_adv_dig_filtr = true,
>         .has_ana_filtr = true,
> +       .has_clear_cmd = false, /* due to errata, CLEAR cmd is not working */
>  };
> 
>  static struct at91_twi_pdata sam9x60_config = {
> @@ -142,6 +143,7 @@ static struct at91_twi_pdata sam9x60_config = {
>         .has_dig_filtr = true,
>         .has_adv_dig_filtr = true,
>         .has_ana_filtr = 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 0aba51a7df32..bcc05a8fe826 100644
> --- a/drivers/i2c/busses/i2c-at91-master.c
> +++ b/drivers/i2c/busses/i2c-at91-master.c
> @@ -480,7 +480,7 @@ 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;
> -       struct i2c_bus_recovery_info *rinfo = &dev->rinfo;
> +       bool has_clear_cmd = dev->pdata->has_clear_cmd;
> 
>         /*
>          * WARNING: the TXCOMP bit in the Status Register is NOT a clear on
> @@ -641,10 +641,32 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev)
>                                AT91_TWI_THRCLR | AT91_TWI_LOCKCLR);
>         }
> 
> -       if (rinfo->get_sda && !(rinfo->get_sda(&dev->adapter))) {
> -               dev_dbg(dev->dev,
> -                       "SDA is down; clear bus using gpio\n");
> -               i2c_recover_bus(&dev->adapter);
> +       /*
> +        * some faulty I2C slave devices might hold SDA down;
> +        * we can send a bus clear command, hoping that the pins will be
> +        * released
> +        */
> +       if (has_clear_cmd) {
> +               if (!(dev->transfer_status & AT91_TWI_SDA)) {
> +                       dev_dbg(dev->dev,
> +                               "SDA is 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);
> +               }
> +       } else {
> +               struct i2c_bus_recovery_info *rinfo = &dev->rinfo;
> +
> +               if (rinfo->get_sda && !(rinfo->get_sda(&dev->adapter))) {
> +                       dev_dbg(dev->dev,
> +                               "SDA is down; clear bus using gpio\n");
> +                       i2c_recover_bus(&dev->adapter);
> +               }
>         }
> 
>         return ret;
> diff --git a/drivers/i2c/busses/i2c-at91.h b/drivers/i2c/busses/i2c-at91.h
> index f57a6cab96b4..7e7b4955ca7f 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_FILTR         0x0044
> @@ -118,6 +122,7 @@ struct at91_twi_pdata {
>         bool has_dig_filtr;
>         bool has_adv_dig_filtr;
>         bool has_ana_filtr;
> +       bool has_clear_cmd;
>         struct at_dma_slave dma_slave;
>  };
> 
> --
> 2.20.1
> 

Re: [PATCH v3 4/6] ARM: at91/dt: sama5d3: add i2c gpio pinctrl

[Ludovic Desroches]

On Wed, Jan 15, 2020 at 01:54:20PM +0200, Codrin Ciubotariu wrote:
> From: Kamel Bouhara <kamel.bouhara@bootlin.com>
> 
> Add the i2c gpio pinctrls to support the i2c bus recovery
> 
> Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
> [codrin.ciubotariu@microchip.com: removed gpio pull-ups]
> Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>

> ---
> 
> Changes in v3:
>  - removed gpio pull-ups;
> 
> Changes in v2:
>   - none;
> 
>  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..1cea2137decf 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_NONE
> +							 AT91_PIOA 31 AT91_PERIPH_GPIO AT91_PINCTRL_NONE>;
> +					};
>  				};
>  
>  				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_NONE
> +							 AT91_PIOC 27 AT91_PERIPH_GPIO AT91_PINCTRL_NONE>;
> +					};
>  				};
>  
>  				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_NONE
> +							 AT91_PIOA 19 AT91_PERIPH_GPIO AT91_PINCTRL_NONE>;
> +					};
>  				};
>  
>  				isi {
> -- 
> 2.20.1
> 

Re: [PATCH v3 5/6] ARM: at91/dt: sama5d4: add i2c gpio pinctrl

[Ludovic Desroches]

On Wed, Jan 15, 2020 at 01:54:21PM +0200, Codrin Ciubotariu wrote:
> From: Kamel Bouhara <kamel.bouhara@bootlin.com>
> 
> Add the i2c gpio pinctrls so the i2c bus recovery option can be enabled
> 
> Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
> [codrin.ciubotariu@microchip.com: removed gpio pull-ups]
> Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>

> ---
> 
> Changes in v3:
>  - removed gpio pull-ups;
> 
> Changes in v2:
>  - none;
> 
>  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..26ce868096c2 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_NONE
> +							 AT91_PIOA 31 AT91_PERIPH_GPIO AT91_PINCTRL_NONE>;
> +					};
>  				};
>  
>  				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_NONE
> +							 AT91_PIOE 30 AT91_PERIPH_GPIO AT91_PINCTRL_NONE>;
> +					};
>  				};
>  
>  				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_NONE
> +							 AT91_PIOB 30 AT91_PERIPH_GPIO AT91_PINCTRL_NONE>;
> +					};
>  				};
>  
>  				isi {
> -- 
> 2.20.1
> 

Re: [PATCH v3 6/6] ARM: at91/dt: sama5d2: add i2c gpio pinctrl

[Ludovic Desroches]

On Wed, Jan 15, 2020 at 01:54:22PM +0200, Codrin Ciubotariu wrote:
> From: Kamel Bouhara <kamel.bouhara@bootlin.com>
> 
> Add the i2c gpio pinctrls to support the i2c bus recovery
> 
> Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
> [codrin.ciubotariu@microchip.com: removed gpio pull-ups]
> Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>

> ---
> 
> Changes in v3:
>  - removed gpio pull-ups;
> 
> Changes in v2:
>  - new patch;
> 
>  arch/arm/boot/dts/at91-sama5d2_ptc_ek.dts   | 33 +++++++++++++++++++--
>  arch/arm/boot/dts/at91-sama5d2_xplained.dts | 33 +++++++++++++++++++--
>  2 files changed, 60 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/arm/boot/dts/at91-sama5d2_ptc_ek.dts b/arch/arm/boot/dts/at91-sama5d2_ptc_ek.dts
> index ba7f3e646c26..1c24ac8019ba 100644
> --- a/arch/arm/boot/dts/at91-sama5d2_ptc_ek.dts
> +++ b/arch/arm/boot/dts/at91-sama5d2_ptc_ek.dts
> @@ -180,8 +180,11 @@
>  
>  			i2c0: i2c@f8028000 {
>  				dmas = <0>, <0>;
> -				pinctrl-names = "default";
> +				pinctrl-names = "default", "gpio";
>  				pinctrl-0 = <&pinctrl_i2c0_default>;
> +				pinctrl-1 = <&pinctrl_i2c0_gpio>;
> +				sda-gpios = <&pioA PIN_PD21 GPIO_ACTIVE_HIGH>;
> +				scl-gpios = <&pioA PIN_PD22 GPIO_ACTIVE_HIGH>;
>  				status = "okay";
>  			};
>  
> @@ -198,8 +201,11 @@
>  					#address-cells = <1>;
>  					#size-cells = <0>;
>  					clocks = <&pmc PMC_TYPE_PERIPHERAL 19>;
> -					pinctrl-names = "default";
> +					pinctrl-names = "default", "gpio";
>  					pinctrl-0 = <&pinctrl_flx0_default>;
> +					pinctrl-1 = <&pinctrl_flx0_gpio>;
> +					sda-gpios = <&pioA PIN_PB28 GPIO_ACTIVE_HIGH>;
> +					scl-gpios = <&pioA PIN_PB29 GPIO_ACTIVE_HIGH>;
>  					atmel,fifo-size = <16>;
>  					status = "okay";
>  				};
> @@ -226,8 +232,11 @@
>  
>  			i2c1: i2c@fc028000 {
>  				dmas = <0>, <0>;
> -				pinctrl-names = "default";
> +				pinctrl-names = "default", "gpio";
>  				pinctrl-0 = <&pinctrl_i2c1_default>;
> +				pinctrl-1 = <&pinctrl_i2c1_gpio>;
> +				sda-gpios = <&pioA PIN_PC6 GPIO_ACTIVE_HIGH>;
> +				scl-gpios = <&pioA PIN_PC7 GPIO_ACTIVE_HIGH>;
>  				status = "okay";
>  
>  				at24@50 {
> @@ -244,18 +253,36 @@
>  					bias-disable;
>  				};
>  
> +				pinctrl_flx0_gpio: flx0_gpio {
> +					pinmux = <PIN_PB28__GPIO>,
> +						 <PIN_PB29__GPIO>;
> +					bias-disable;
> +				};
> +
>  				pinctrl_i2c0_default: i2c0_default {
>  					pinmux = <PIN_PD21__TWD0>,
>  						 <PIN_PD22__TWCK0>;
>  					bias-disable;
>  				};
>  
> +				pinctrl_i2c0_gpio: i2c0_gpio {
> +					pinmux = <PIN_PD21__GPIO>,
> +						 <PIN_PD22__GPIO>;
> +					bias-disable;
> +				};
> +
>  				pinctrl_i2c1_default: i2c1_default {
>  					pinmux = <PIN_PC6__TWD1>,
>  						 <PIN_PC7__TWCK1>;
>  					bias-disable;
>  				};
>  
> +				pinctrl_i2c1_gpio: i2c1_gpio {
> +					pinmux = <PIN_PC6__GPIO>,
> +						 <PIN_PC7__GPIO>;
> +					bias-disable;
> +				};
> +
>  				pinctrl_key_gpio_default: key_gpio_default {
>  					pinmux = <PIN_PA10__GPIO>;
>  					bias-pull-up;
> diff --git a/arch/arm/boot/dts/at91-sama5d2_xplained.dts b/arch/arm/boot/dts/at91-sama5d2_xplained.dts
> index 9d0a7fbea725..055ee53e4773 100644
> --- a/arch/arm/boot/dts/at91-sama5d2_xplained.dts
> +++ b/arch/arm/boot/dts/at91-sama5d2_xplained.dts
> @@ -129,8 +129,11 @@
>  
>  			i2c0: i2c@f8028000 {
>  				dmas = <0>, <0>;
> -				pinctrl-names = "default";
> +				pinctrl-names = "default", "gpio";
>  				pinctrl-0 = <&pinctrl_i2c0_default>;
> +				pinctrl-1 = <&pinctrl_i2c0_gpio>;
> +				sda-gpios = <&pioA PIN_PD21 GPIO_ACTIVE_HIGH>;
> +				scl-gpios = <&pioA PIN_PD22 GPIO_ACTIVE_HIGH>;
>  				i2c-sda-hold-time-ns = <350>;
>  				status = "okay";
>  
> @@ -331,8 +334,11 @@
>  					#address-cells = <1>;
>  					#size-cells = <0>;
>  					clocks = <&pmc PMC_TYPE_PERIPHERAL 23>;
> -					pinctrl-names = "default";
> +					pinctrl-names = "default", "gpio";
>  					pinctrl-0 = <&pinctrl_flx4_default>;
> +					pinctrl-1 = <&pinctrl_flx4_gpio>;
> +					sda-gpios = <&pioA PIN_PD12 GPIO_ACTIVE_HIGH>;
> +					scl-gpios = <&pioA PIN_PD13 GPIO_ACTIVE_HIGH>;
>  					atmel,fifo-size = <16>;
>  					i2c-analog-filter;
>  					i2c-digital-filter;
> @@ -343,11 +349,14 @@
>  
>  			i2c1: i2c@fc028000 {
>  				dmas = <0>, <0>;
> -				pinctrl-names = "default";
> +				pinctrl-names = "default", "gpio";
>  				pinctrl-0 = <&pinctrl_i2c1_default>;
>  				i2c-analog-filter;
>  				i2c-digital-filter;
>  				i2c-digital-filter-width-ns = <35>;
> +				pinctrl-1 = <&pinctrl_i2c1_gpio>;
> +				sda-gpios = <&pioA PIN_PD4 GPIO_ACTIVE_HIGH>;
> +				scl-gpios = <&pioA PIN_PD5 GPIO_ACTIVE_HIGH>;
>  				status = "okay";
>  
>  				at24@54 {
> @@ -441,18 +450,36 @@
>  					bias-disable;
>  				};
>  
> +				pinctrl_flx4_gpio: flx4_gpio {
> +					pinmux = <PIN_PD12__GPIO>,
> +						 <PIN_PD13__GPIO>;
> +					bias-disable;
> +				};
> +
>  				pinctrl_i2c0_default: i2c0_default {
>  					pinmux = <PIN_PD21__TWD0>,
>  						 <PIN_PD22__TWCK0>;
>  					bias-disable;
>  				};
>  
> +				pinctrl_i2c0_gpio: i2c0_gpio {
> +					pinmux = <PIN_PD21__GPIO>,
> +						 <PIN_PD22__GPIO>;
> +					bias-disable;
> +				};
> +
>  				pinctrl_i2c1_default: i2c1_default {
>  					pinmux = <PIN_PD4__TWD1>,
>  						 <PIN_PD5__TWCK1>;
>  					bias-disable;
>  				};
>  
> +				pinctrl_i2c1_gpio: i2c1_gpio {
> +					pinmux = <PIN_PD4__GPIO>,
> +						 <PIN_PD5__GPIO>;
> +					bias-disable;
> +				};
> +
>  				pinctrl_i2s0_default: i2s0_default {
>  					pinmux = <PIN_PC1__I2SC0_CK>,
>  						 <PIN_PC2__I2SC0_MCK>,
> -- 
> 2.20.1
> 

Re: [PATCH v3 1/6] dt-bindings: i2c: at91: document optional bus recovery properties

[Wolfram Sang]

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On Wed, Jan 15, 2020 at 01:54:17PM +0200, Codrin Ciubotariu wrote:
> From: Kamel Bouhara <kamel.bouhara@bootlin.com>
> 
> 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>
> [codrin.ciubotariu@microchip.com: rebased]
> Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
> Reviewed-by: Rob Herring <robh@kernel.org>

Applied to for-next, thanks!


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Re: [PATCH v3 2/6] i2c: at91: implement i2c bus recovery

[Wolfram Sang]

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On Wed, Jan 15, 2020 at 01:54:18PM +0200, Codrin Ciubotariu wrote:
> From: Kamel Bouhara <kamel.bouhara@bootlin.com>
> 
> 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>
> Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>

Applied to for-next, thanks!

The implementation is very similar to i2c-imx. Maybe we should move this
mechanism into the core somewhen...


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Re: [PATCH v3 3/6] i2c: at91: Send bus clear command if SDA is down

[Wolfram Sang]

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On Wed, Jan 15, 2020 at 01:54:19PM +0200, Codrin Ciubotariu wrote:
> After a transfer timeout, some faulty I2C slave devices might hold down
> the SDA pin. We can generate a bus clear command, hoping that the slave
> might release the pins.
> If the CLEAR command is not supported, we will use gpio recovery, if
> available, to reset the bus.
> 
> Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>

One thing to improve:

> +	/*
> +	 * some faulty I2C slave devices might hold SDA down;
> +	 * we can send a bus clear command, hoping that the pins will be
> +	 * released
> +	 */
> +	if (has_clear_cmd) {
> +		if (!(dev->transfer_status & AT91_TWI_SDA)) {
> +			dev_dbg(dev->dev,
> +				"SDA is 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);
> +		}

The inner if-block should be a seperate function, then you could do in
probe:

	if (has_clear_cmd)
		rinfo->recover_bus = <the above function>;
	else
		rinfo->recover_bus = i2c_generic_scl_recovery;

Then, i2c_recover_bus() will always do the right thing. More readable
and better maintainable IMO.

If this is not possible (maybe I overlooked some logic), then maybe this
will work:

	rinfo->recover_bus = <your custom function>;

and put the

	if (has_clear_cmd)

block there.


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