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Date: Wed, 11 May 2016 23:04:17 +0530 From: Abhishek Sahu <absahu@...eaurora.org> To: Sricharan <sricharan@...eaurora.org> Cc: agross@...eaurora.org, architt@...eaurora.org, linux-arm-msm@...r.kernel.org, ntelkar@...eaurora.org, linux-kernel@...r.kernel.org, andy.gross@...aro.org, linux-i2c@...r.kernel.org, dmaengine@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, wsa@...-dreams.de Subject: RE: [PATCH 1/2] i2c: qup: Cleared the error bits in ISR On 2016-05-11 21:27, Sricharan wrote: > Hi, > >> 1. Current QCOM I2C driver hangs when sending data to address >> 0x03-0x07 >> in some scenarios. The QUP controller generates invalid write in this >> case, >> since these addresses are reserved for different bus formats. >> >> 2. Also, the error handling is done by I2C QUP ISR in the case of DMA >> mode. >> The state need to be RESET in case of any error for clearing the >> available >> data in FIFO, which otherwise leaves the BAM DMA controller in hang >> state. >> >> This patch fixes the above two issues by clearing the error bits from >> I2C >> and >> QUP status in ISR in case of I2C error, QUP error and resets the QUP >> state >> to >> clear the FIFO data. >> >> Signed-off-by: Abhishek Sahu <absahu@...eaurora.org> >> --- >> drivers/i2c/busses/i2c-qup.c | 14 ++++++++------ >> 1 file changed, 8 insertions(+), 6 deletions(-) >> >> diff --git a/drivers/i2c/busses/i2c-qup.c >> b/drivers/i2c/busses/i2c-qup.c >> index >> 23eaabb..8c2f1bc 100644 >> --- a/drivers/i2c/busses/i2c-qup.c >> +++ b/drivers/i2c/busses/i2c-qup.c >> @@ -213,14 +213,16 @@ static irqreturn_t qup_i2c_interrupt(int irq, >> void >> *dev) >> bus_err &= I2C_STATUS_ERROR_MASK; >> qup_err &= QUP_STATUS_ERROR_FLAGS; >> >> - if (qup_err) { >> - /* Clear Error interrupt */ >> + /* Clear the error bits in QUP_ERROR_FLAGS */ >> + if (qup_err) >> writel(qup_err, qup->base + QUP_ERROR_FLAGS); >> - goto done; >> - } >> >> - if (bus_err) { >> - /* Clear Error interrupt */ >> + /* Clear the error bits in QUP_I2C_STATUS */ >> + if (bus_err) >> + writel(bus_err, qup->base + QUP_I2C_STATUS); >> + >> + /* Reset the QUP State in case of error */ >> + if (qup_err || bus_err) { >> writel(QUP_RESET_STATE, qup->base + QUP_STATE); >> goto done; >> } > In qup_i2c_xfer and qup_i2c_xfer_v2 state is set to RESET at the > end, when > there is no error. So would it be fine if we do it there > unconditionally ? > > Regards, > Sricharan RESET the QUP state wouldn't create any issue in the case of multiple calls. The existing code also RESET the QUP state for bus_err but it is not clearing status bits. -- Abhishek Sahu
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