Implement bus recovery methods for i2c-imx so we can recover from
situations where SCL/SDA are stuck low.
Once i2c bus SCL/SDA are stuck low during transfer, config the i2c
pinctrl to gpio mode by calling pinctrl sleep set function, and then
use GPIO to emulate the i2c protocol to send nine dummy clock to recover
i2c device. After recovery, set i2c pinctrl to default group setting.
Signed-off-by: Fugang Duan <B38611@xxxxxxxxxxxxx>
Signed-off-by: Gao Pan <b54642@xxxxxxxxxxxxx>
Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
---
V2:
As Uwe Kleine-König's suggestion, the version do below changes:
-replace of_get_named_gpio() with devm_gpiod_get_optional()
-move gpio_direction_input() and gpio_direction_output() call to the
prepare callback
-use 0 and 1 as return value for the get_scl and get_sda callbacks
V3:
-replace "...-gpio" with "...-gpios" in i2c binding doc
-document the requirement of using sleep state to configure
the pins as gpio in i2c binding doc
-remove i2c_recover_bus() in i2c_imx_trx_complete()
-use GPIOD_OUT_HIGH as the parameter of devm_gpiod_get_optional to
config the gpios as output high
-add error disposal as devm_gpiod_get_optional meets error
V4:
-remove include <linux/of_gpio.h>
-call i2c_recover_bus under the condition of the existing of
both sda and scl. Drop the sda and scl check in i2c_imx_get_scl,
i2c_imx_get_sda, i2c_imx_set_scl, i2c_imx_prepare_recovery and
i2c_imx_prepare_recovery
-use GPIOD_OUT_IN as the parameter of devm_gpiod_get_optional
-remove documenting the requirement of using sleep state to configure
the pins as gpio in i2c binding doc
V5:
-introduce a dedicated gpio state for bus recovery.
-assign adapter.bus_recovery_info after the two gpios were aquired successfully
V6:
-assign adapter.bus_recovery_info under the condition that gpios are acquired successfully
-not try the recovery when pinctrl_lookup_state returns an error
V7:
-execute the bus recovery once in a transfer, when the controller fails to start
-use i2c_generic_gpio_recovery() to handle the bus recovery with gpios
V8:
-remove unused symbol and unrelated whitespace changes
Documentation/devicetree/bindings/i2c/i2c-imx.txt | 9 +++
drivers/i2c/busses/i2c-imx.c | 71 +++++++++++++++++++++++
2 files changed, 80 insertions(+)
diff --git a/Documentation/devicetree/bindings/i2c/i2c-imx.txt b/Documentation/devicetree/bindings/i2c/i2c-imx.txt
index ce4311d..eab5836 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-imx.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-imx.txt
@@ -14,6 +14,10 @@ Optional properties:
The absence of the propoerty indicates the default frequency 100 kHz.
- dmas: A list of two dma specifiers, one for each entry in dma-names.
- dma-names: should contain "tx" and "rx".
+- 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
Examples:
@@ -37,4 +41,9 @@ i2c0: i2c@40066000 { /* i2c0 on vf610 */
dmas = <&edma0 0 50>,
<&edma0 0 51>;
dma-names = "rx","tx";
+ pinctrl-names = "default", "gpio";
+ pinctrl-0 = <&pinctrl_i2c1>;
+ pinctrl-1 = <&pinctrl_i2c1_gpio>;
+ scl-gpios = <&gpio5 26 GPIO_ACTIVE_HIGH>;
+ sda-gpios = <&gpio5 27 GPIO_ACTIVE_HIGH>;
};
diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index 785aa67..8d46e74 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -49,6 +49,7 @@
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_dma.h>
+#include <linux/of_gpio.h>
#include <linux/platform_data/i2c-imx.h>
#include <linux/platform_device.h>
#include <linux/sched.h>
@@ -207,6 +208,11 @@ struct imx_i2c_struct {
unsigned int cur_clk;
unsigned int bitrate;
const struct imx_i2c_hwdata *hwdata;
+ struct i2c_bus_recovery_info rinfo;
+
+ struct pinctrl *pinctrl;
+ struct pinctrl_state *pinctrl_pins_default;
+ struct pinctrl_state *pinctrl_pins_gpio;
struct imx_i2c_dma *dma;
};
@@ -896,6 +902,13 @@ static int i2c_imx_xfer(struct i2c_adapter *adapter,
/* Start I2C transfer */
result = i2c_imx_start(i2c_imx);
+ if (result) {
+ if (i2c_imx->adapter.bus_recovery_info) {
+ i2c_recover_bus(&i2c_imx->adapter);
+ result = i2c_imx_start(i2c_imx);
+ }
+ }
+
if (result)
goto fail0;
@@ -956,6 +969,55 @@ fail0:
return (result < 0) ? result : num;
}
+static void i2c_imx_prepare_recovery(struct i2c_adapter *adap)
+{
+ struct imx_i2c_struct *i2c_imx;
+
+ i2c_imx = container_of(adap, struct imx_i2c_struct, adapter);
+
+ pinctrl_select_state(i2c_imx->pinctrl, i2c_imx->pinctrl_pins_gpio);
+}
+
+static void i2c_imx_unprepare_recovery(struct i2c_adapter *adap)
+{
+ struct imx_i2c_struct *i2c_imx;
+
+ i2c_imx = container_of(adap, struct imx_i2c_struct, adapter);
+
+ pinctrl_select_state(i2c_imx->pinctrl, i2c_imx->pinctrl_pins_default);
+}
+
+static void i2c_imx_init_recovery_info(struct imx_i2c_struct *i2c_imx,
+ struct platform_device *pdev)
+{
+ struct i2c_bus_recovery_info *rinfo = &i2c_imx->rinfo;
+
+ i2c_imx->pinctrl_pins_default = pinctrl_lookup_state(i2c_imx->pinctrl,
+ PINCTRL_STATE_DEFAULT);
+ i2c_imx->pinctrl_pins_gpio = pinctrl_lookup_state(i2c_imx->pinctrl,
+ "gpio");
+ rinfo->sda_gpio = of_get_named_gpio_flags(pdev->dev.of_node,
+ "sda-gpios", 0, NULL);
+ rinfo->scl_gpio = of_get_named_gpio_flags(pdev->dev.of_node,
+ "scl-gpios", 0, NULL);
+
+ if (!gpio_is_valid(rinfo->sda_gpio) ||
+ !gpio_is_valid(rinfo->scl_gpio) ||
+ IS_ERR(i2c_imx->pinctrl_pins_default) ||
+ IS_ERR(i2c_imx->pinctrl_pins_gpio)) {
+ dev_dbg(&pdev->dev, "recovery information incomplete\n");
+ return;
+ }
+
+ dev_dbg(&pdev->dev, "using scl-gpio %d and sda-gpio %d for recovery\n",
+ rinfo->sda_gpio, rinfo->scl_gpio);
+
+ rinfo->prepare_recovery = i2c_imx_prepare_recovery;
+ rinfo->unprepare_recovery = i2c_imx_unprepare_recovery;
+ rinfo->recover_bus = i2c_generic_gpio_recovery;
+ i2c_imx->adapter.bus_recovery_info = rinfo;
+}
+
static u32 i2c_imx_func(struct i2c_adapter *adapter)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL
@@ -1023,6 +1085,13 @@ static int i2c_imx_probe(struct platform_device *pdev)
dev_err(&pdev->dev, "can't enable I2C clock\n");
return ret;
}
+
+ i2c_imx->pinctrl = devm_pinctrl_get(&pdev->dev);
+ if (IS_ERR(i2c_imx->pinctrl)) {
+ ret = PTR_ERR(i2c_imx->pinctrl);
+ goto clk_disable;
+ }
+
/* Request IRQ */
ret = devm_request_irq(&pdev->dev, irq, i2c_imx_isr, 0,
pdev->name, i2c_imx);
@@ -1056,6 +1125,8 @@ static int i2c_imx_probe(struct platform_device *pdev)
goto clk_disable;
}
+ i2c_imx_init_recovery_info(i2c_imx, pdev);
+
/* Set up platform driver data */
platform_set_drvdata(pdev, i2c_imx);
clk_disable_unprepare(i2c_imx->clk);
--
1.9.1
--
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