Messages in this thread Patch in this message | | | Subject | Re: [PATCH V4] i2c: designware: fix wrong Tx/Rx FIFO for ACPI | From | Andy Shevchenko <> | Date | Tue, 13 Dec 2016 13:25:37 +0200 |
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On Tue, 2016-12-13 at 17:03 +0700, Tin Huynh wrote: > ACPI always sets Tx/Rx FIFO to 32. This configuration will > cause problem if the IP core supports a FIFO size of less than 32. > The driver should read the FIFO size from the IP and select the > smaller > one of the two. > > Signed-off-by: Tin Huynh <tnhuynh@apm.com> >
One comment below, after addressing it
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> --- > drivers/i2c/busses/i2c-designware-platdrv.c | 27 > ++++++++++++++++++++------- > 1 files changed, 20 insertions(+), 7 deletions(-) > > Change from V3: > -Use uppercase of FIFO instead of lowercase. > -Fix the problem when IP core return 0 of FIFO. > > Change from V2: > -Add a helper function to set FIFO size. > > Change from V1: > -Revert the default 32 for FIFO, read parameter from IP core > and pick the smaller one of the two. > -Correct the title to describe new approach. > > diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c > b/drivers/i2c/busses/i2c-designware-platdrv.c > index 0b42a12..24032d6 100644 > --- a/drivers/i2c/busses/i2c-designware-platdrv.c > +++ b/drivers/i2c/busses/i2c-designware-platdrv.c > @@ -150,6 +150,25 @@ static int i2c_dw_plat_prepare_clk(struct > dw_i2c_dev *i_dev, bool prepare) > return 0; > } > > +static void dw_i2c_set_fifo_size(struct dw_i2c_dev *dev, int id) > +{ > + u32 param, tx_fifo_depth, rx_fifo_depth; > + >
/* * Try to detect the FIFO depth if not set by interface driver, * the depth could be from 2 to 256 from HW spec. */
> + param = i2c_dw_read_comp_param(dev); > + tx_fifo_depth = ((param >> 16) & 0xff) + 1; > + rx_fifo_depth = ((param >> 8) & 0xff) + 1; > + if (!dev->tx_fifo_depth) { > + dev->tx_fifo_depth = tx_fifo_depth; > + dev->rx_fifo_depth = rx_fifo_depth; > + dev->adapter.nr = id; > + } else if (tx_fifo_depth > 1) {
This makes sense now, though I would add a comment here and use >= 2 to reflect datasheet.
/* * Choose minimum values between HW and interface * driver provided. */
> + dev->tx_fifo_depth = min_t(u32, dev->tx_fifo_depth, > + tx_fifo_depth); > + dev->rx_fifo_depth = min_t(u32, dev->rx_fifo_depth, > + rx_fifo_depth); > + } > +} > + > static int dw_i2c_plat_probe(struct platform_device *pdev) > { > struct dw_i2c_platform_data *pdata = dev_get_platdata(&pdev- > >dev); > @@ -246,13 +265,7 @@ static int dw_i2c_plat_probe(struct > platform_device *pdev) > 1000000); > } > > - if (!dev->tx_fifo_depth) { > - u32 param1 = i2c_dw_read_comp_param(dev); > - > - dev->tx_fifo_depth = ((param1 >> 16) & 0xff) + 1; > - dev->rx_fifo_depth = ((param1 >> 8) & 0xff) + 1; > - dev->adapter.nr = pdev->id; > - } > + dw_i2c_set_fifo_size(dev, pdev->id); > > adap = &dev->adapter; > adap->owner = THIS_MODULE;
-- Andy Shevchenko <andriy.shevchenko@linux.intel.com> Intel Finland Oy
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