[PATCH v2 6/6] i2c: i2c-stm32f7: Implement I2C recovery mechanism
From: Wolfram Sang <hidden>
Date: 2018-03-24 22:56:33
Also in:
linux-i2c, lkml
On Wed, Mar 21, 2018 at 05:49:00PM +0100, Pierre-Yves MORDRET wrote:
Feature prevents I2C lock-ups. Mechanism resets I2C state machine
and releases SCL/SDA signals but preserves I2C registers.
Signed-off-by: Pierre-Yves MORDRET <redacted>
---
Version history:
v1:
* Initial
v2:
* Don't use i2c engine recovery mechanism since driver
procedure only recover master and not the slave.s/recovery/release/ throughout the patch, please. Recovery is really something else. Also, I think the dev_info's are too noisy in the log files. I'd think the whole driver could be lifted from quite some logging...
quoted hunk ↗ jump to hunk
--- --- drivers/i2c/busses/i2c-stm32f7.c | 27 ++++++++++++++++++++++++--- 1 file changed, 24 insertions(+), 3 deletions(-)diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c index 91f73e0..9a9c469 100644 --- a/drivers/i2c/busses/i2c-stm32f7.c +++ b/drivers/i2c/busses/i2c-stm32f7.c@@ -718,6 +718,20 @@ static void stm32f7_i2c_smbus_reload(struct stm32f7_i2c_dev *i2c_dev) writel_relaxed(cr2, i2c_dev->base + STM32F7_I2C_CR2); } +static int stm32f7_i2c_recover_bus(struct i2c_adapter *i2c_adap) +{ + struct stm32f7_i2c_dev *i2c_dev = i2c_get_adapdata(i2c_adap); + + dev_info(i2c_dev->dev, "Trying to recover bus\n"); + + stm32f7_i2c_clr_bits(i2c_dev->base + STM32F7_I2C_CR1, + STM32F7_I2C_CR1_PE); + + stm32f7_i2c_hw_config(i2c_dev); + + return 0; +} + static int stm32f7_i2c_wait_free_bus(struct stm32f7_i2c_dev *i2c_dev) { u32 status;@@ -727,12 +741,18 @@ static int stm32f7_i2c_wait_free_bus(struct stm32f7_i2c_dev *i2c_dev) status, !(status & STM32F7_I2C_ISR_BUSY), 10, 1000); + if (!ret) + return 0; + + dev_info(i2c_dev->dev, "bus busy\n"); + + ret = stm32f7_i2c_recover_bus(&i2c_dev->adap); if (ret) { - dev_dbg(i2c_dev->dev, "bus busy\n"); - ret = -EBUSY; + dev_err(i2c_dev->dev, "Failed to recover the bus (%d)\n", ret); + return ret; } - return ret; + return -EBUSY; } static void stm32f7_i2c_xfer_msg(struct stm32f7_i2c_dev *i2c_dev,@@ -1474,6 +1494,7 @@ static irqreturn_t stm32f7_i2c_isr_error(int irq, void *data) if (status & STM32F7_I2C_ISR_BERR) { dev_err(dev, "<%s>: Bus error\n", __func__); writel_relaxed(STM32F7_I2C_ICR_BERRCF, base + STM32F7_I2C_ICR); + stm32f7_i2c_recover_bus(&i2c_dev->adap); f7_msg->result = -EIO; }-- 2.7.4
-------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 833 bytes Desc: not available URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20180324/9f7906c0/attachment-0001.sig>