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Wed, 7 Feb 2018 16:35:53 +0100 From: Pierre-Yves MORDRET To: Wolfram Sang , Maxime Coquelin , Alexandre Torgue , , , Subject: [PATCH 6/6] i2c: i2c-stm32f7: Implement I2C recovery mechanism Date: Wed, 7 Feb 2018 16:35:17 +0100 Message-ID: <1518017717-10351-7-git-send-email-pierre-yves.mordret@st.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1518017717-10351-1-git-send-email-pierre-yves.mordret@st.com> References: <1518017717-10351-1-git-send-email-pierre-yves.mordret@st.com> MIME-Version: 1.0 X-Originating-IP: [10.75.127.46] X-ClientProxiedBy: SFHDAG8NODE2.st.com (10.75.127.23) To SFHDAG5NODE2.st.com (10.75.127.14) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2018-02-07_04:, , signatures=0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180207_153611_521934_CC4A8163 X-CRM114-Status: GOOD ( 15.24 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Pierre-Yves MORDRET Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP 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 --- Version history: v1: * Initial --- --- drivers/i2c/busses/i2c-stm32f7.c | 32 +++++++++++++++++++++++++++++--- 1 file changed, 29 insertions(+), 3 deletions(-) diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c index 593efa5..428bf96 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 = 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, @@ -1476,6 +1496,7 @@ 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); + i2c_recover_bus(&i2c_dev->adap); f7_msg->result = -EIO; } @@ -1760,6 +1781,10 @@ static struct i2c_algorithm stm32f7_i2c_algo = { .unreg_slave = stm32f7_i2c_unreg_slave, }; +static struct i2c_bus_recovery_info stm32f7_i2c_recovery_info = { + .recover_bus = stm32f7_i2c_recover_bus, +}; + static int stm32f7_i2c_probe(struct platform_device *pdev) { struct device_node *np = pdev->dev.of_node; @@ -1879,6 +1904,7 @@ static int stm32f7_i2c_probe(struct platform_device *pdev) adap->algo = &stm32f7_i2c_algo; adap->dev.parent = &pdev->dev; adap->dev.of_node = pdev->dev.of_node; + adap->bus_recovery_info = &stm32f7_i2c_recovery_info; init_completion(&i2c_dev->complete);