Add bus recovery feature for LPI2C.
Need add gpio pinctrl, scl-gpios and sda-gpios configuration in dts.
Signed-off-by: Clark Wang <xiaoning.wang@xxxxxxx>
---
V2 changes:
- No change. Add dt-bindings in the next patch.
---
drivers/i2c/busses/i2c-imx-lpi2c.c | 83 ++++++++++++++++++++++++++++++
1 file changed, 83 insertions(+)
diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-imx-lpi2c.c
index 77ceb743b282..77dd6ee5a4a8 100644
--- a/drivers/i2c/busses/i2c-imx-lpi2c.c
+++ b/drivers/i2c/busses/i2c-imx-lpi2c.c
@@ -18,6 +18,7 @@
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
+#include <linux/of_gpio.h>
#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
@@ -108,6 +109,11 @@ struct lpi2c_imx_struct {
unsigned int txfifosize;
unsigned int rxfifosize;
enum lpi2c_imx_mode mode;
+
+ struct i2c_bus_recovery_info rinfo;
+ struct pinctrl *pinctrl;
+ struct pinctrl_state *pinctrl_pins_default;
+ struct pinctrl_state *pinctrl_pins_gpio;
};
static void lpi2c_imx_intctrl(struct lpi2c_imx_struct *lpi2c_imx,
@@ -135,6 +141,8 @@ static int lpi2c_imx_bus_busy(struct lpi2c_imx_struct *lpi2c_imx)
if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) {
dev_dbg(&lpi2c_imx->adapter.dev, "bus not work\n");
+ if (lpi2c_imx->adapter.bus_recovery_info)
+ i2c_recover_bus(&lpi2c_imx->adapter);
return -ETIMEDOUT;
}
schedule();
@@ -192,6 +200,8 @@ static void lpi2c_imx_stop(struct lpi2c_imx_struct *lpi2c_imx)
if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) {
dev_dbg(&lpi2c_imx->adapter.dev, "stop timeout\n");
+ if (lpi2c_imx->adapter.bus_recovery_info)
+ i2c_recover_bus(&lpi2c_imx->adapter);
break;
}
schedule();
@@ -329,6 +339,8 @@ static int lpi2c_imx_txfifo_empty(struct lpi2c_imx_struct *lpi2c_imx)
if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) {
dev_dbg(&lpi2c_imx->adapter.dev, "txfifo empty timeout\n");
+ if (lpi2c_imx->adapter.bus_recovery_info)
+ i2c_recover_bus(&lpi2c_imx->adapter);
return -ETIMEDOUT;
}
schedule();
@@ -528,6 +540,71 @@ static irqreturn_t lpi2c_imx_isr(int irq, void *dev_id)
return IRQ_HANDLED;
}
+static void lpi2c_imx_prepare_recovery(struct i2c_adapter *adap)
+{
+ struct lpi2c_imx_struct *lpi2c_imx;
+
+ lpi2c_imx = container_of(adap, struct lpi2c_imx_struct, adapter);
+
+ pinctrl_select_state(lpi2c_imx->pinctrl, lpi2c_imx->pinctrl_pins_gpio);
+}
+
+static void lpi2c_imx_unprepare_recovery(struct i2c_adapter *adap)
+{
+ struct lpi2c_imx_struct *lpi2c_imx;
+
+ lpi2c_imx = container_of(adap, struct lpi2c_imx_struct, adapter);
+
+ pinctrl_select_state(lpi2c_imx->pinctrl, lpi2c_imx->pinctrl_pins_default);
+}
+
+/*
+ * We switch SCL and SDA to their GPIO function and do some bitbanging
+ * for bus recovery. These alternative pinmux settings can be
+ * described in the device tree by a separate pinctrl state "gpio". If
+ * this is missing this is not a big problem, the only implication is
+ * that we can't do bus recovery.
+ */
+static int lpi2c_imx_init_recovery_info(struct lpi2c_imx_struct *lpi2c_imx,
+ struct platform_device *pdev)
+{
+ struct i2c_bus_recovery_info *rinfo = &lpi2c_imx->rinfo;
+
+ lpi2c_imx->pinctrl = devm_pinctrl_get(&pdev->dev);
+ if (!lpi2c_imx->pinctrl || IS_ERR(lpi2c_imx->pinctrl)) {
+ dev_info(&pdev->dev, "can't get pinctrl, bus recovery not supported\n");
+ return PTR_ERR(lpi2c_imx->pinctrl);
+ }
+
+ lpi2c_imx->pinctrl_pins_default = pinctrl_lookup_state(lpi2c_imx->pinctrl,
+ PINCTRL_STATE_DEFAULT);
+ lpi2c_imx->pinctrl_pins_gpio = pinctrl_lookup_state(lpi2c_imx->pinctrl,
+ "gpio");
+ rinfo->sda_gpiod = devm_gpiod_get(&pdev->dev, "sda", GPIOD_IN);
+ rinfo->scl_gpiod = devm_gpiod_get(&pdev->dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN);
+
+ if (PTR_ERR(rinfo->sda_gpiod) == -EPROBE_DEFER ||
+ PTR_ERR(rinfo->scl_gpiod) == -EPROBE_DEFER) {
+ return -EPROBE_DEFER;
+ } else if (IS_ERR(rinfo->sda_gpiod) ||
+ IS_ERR(rinfo->scl_gpiod) ||
+ IS_ERR(lpi2c_imx->pinctrl_pins_default) ||
+ IS_ERR(lpi2c_imx->pinctrl_pins_gpio)) {
+ dev_dbg(&pdev->dev, "recovery information incomplete\n");
+ return 0;
+ }
+
+ dev_info(&pdev->dev, "using scl%s for recovery\n",
+ rinfo->sda_gpiod ? ",sda" : "");
+
+ rinfo->prepare_recovery = lpi2c_imx_prepare_recovery;
+ rinfo->unprepare_recovery = lpi2c_imx_unprepare_recovery;
+ rinfo->recover_bus = i2c_generic_scl_recovery;
+ lpi2c_imx->adapter.bus_recovery_info = rinfo;
+
+ return 0;
+}
+
static u32 lpi2c_imx_func(struct i2c_adapter *adapter)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
@@ -632,6 +709,12 @@ static int lpi2c_imx_probe(struct platform_device *pdev)
lpi2c_imx->txfifosize = 1 << (temp & 0x0f);
lpi2c_imx->rxfifosize = 1 << ((temp >> 8) & 0x0f);
+ /* Init optional bus recovery function */
+ ret = lpi2c_imx_init_recovery_info(lpi2c_imx, pdev);
+ /* Give it another chance if pinctrl used is not ready yet */
+ if (ret == -EPROBE_DEFER)
+ goto rpm_disable;
+
ret = i2c_add_adapter(&lpi2c_imx->adapter);
if (ret)
goto rpm_disable;
--
2.25.1
