On Wed, Jan 30, 2019 at 10:16:26PM -0800, Sowjanya Komatineni wrote: > Tegra194 allows max of 64K bytes and Tegra186 and prior allows > max of 4K bytes of transfer per packet. > > one sec timeout is not enough for transfers more than 10K bytes > at STD bus rate. > > This patch updates I2C transfer timeout based on the transfer size > and I2C bus rate to allow enough time during max transfer size at > lower bus speed. > > Signed-off-by: Sowjanya Komatineni <skomatineni@xxxxxxxxxx> > --- > [V8] : Added comment with explaination of xfer time calculation > [V5/V6/V7] : Same as V4 > [V4] : V4 series includes bus clear support and this patch is updated with > fixed timeout of 1sec for bus clear operation. > [V3] : Same as V2 > [V2] : Added this patch in V2 series to allow enough time for data transfer > to happen. > This patch has dependency with DMA patch as TEGRA_I2C_TIMEOUT define > takes argument with this patch. > > drivers/i2c/busses/i2c-tegra.c | 19 ++++++++++++++----- > 1 file changed, 14 insertions(+), 5 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c > index 025d63972e50..435518cd91b6 100644 > --- a/drivers/i2c/busses/i2c-tegra.c > +++ b/drivers/i2c/busses/i2c-tegra.c > @@ -25,7 +25,7 @@ > #include <linux/pm_runtime.h> > #include <linux/reset.h> > > -#define TEGRA_I2C_TIMEOUT (msecs_to_jiffies(1000)) > +#define TEGRA_I2C_TIMEOUT(ms) (msecs_to_jiffies(ms)) I think I would've just gone with direct usage of msecs_to_jiffies() but this is also fine. > #define BYTES_PER_FIFO_WORD 4 > > #define I2C_CNFG 0x000 > @@ -901,8 +901,9 @@ static int tegra_i2c_issue_bus_clear(struct tegra_i2c_dev *i2c_dev) > i2c_writel(i2c_dev, reg, I2C_BUS_CLEAR_CNFG); > tegra_i2c_unmask_irq(i2c_dev, I2C_INT_BUS_CLR_DONE); > > - time_left = wait_for_completion_timeout(&i2c_dev->msg_complete, > - TEGRA_I2C_TIMEOUT); > + time_left = wait_for_completion_timeout( > + &i2c_dev->msg_complete, > + TEGRA_I2C_TIMEOUT(1000)); > if (time_left == 0) { > dev_err(i2c_dev->dev, "timed out for bus clear\n"); > return -ETIMEDOUT; > @@ -930,6 +931,7 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev, > int err = 0; > bool dma = false; > struct dma_chan *chan; > + u16 xfer_time = 100; > > tegra_i2c_flush_fifos(i2c_dev); > > @@ -945,6 +947,13 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev, > xfer_size = msg->len + I2C_PACKET_HEADER_SIZE; > > xfer_size = ALIGN(xfer_size, BYTES_PER_FIFO_WORD); > + /* > + * Transfer time = Total bits / transfer rate > + * Total bits = 9 bits per byte (including ACK bit) + Start & stop bits > + */ > + xfer_time += DIV_ROUND_CLOSEST(((xfer_size * 9) + 2) * 1000, This doesn't really explain the factor of 1000 in there, which I assume is just to scale this to milliseconds required by msecs_to_jiffies(). Might be worth to replace it by MSEC_PER_SEC to clarify the purpose. With that fixed: Acked-by: Thierry Reding <treding@xxxxxxxxxx>
Attachment:
signature.asc
Description: PGP signature