On Tue, 2017-03-28 at 16:48 +0800, Tan Chin Yew wrote: > Sda-hold-time is an important parameter for tuning i2c to meet the > electrical specification especially for high speed. I2C with incorrect > sda-hold-time may cause lost arbitration error. Instead of loading all > speed mode settings, only selected speed mode settings are loaded. > > Signed-off-by: Tan Chin Yew <[email protected]>
Looks good to me: Reviewed-by: Andy Shevchenko <[email protected]> > --- > drivers/i2c/busses/i2c-designware-platdrv.c | 31 > ++++++++++++++++++++--------- > 1 file changed, 22 insertions(+), 9 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c > b/drivers/i2c/busses/i2c-designware-platdrv.c > index a597ba32..5a4eb6b 100644 > --- a/drivers/i2c/busses/i2c-designware-platdrv.c > +++ b/drivers/i2c/busses/i2c-designware-platdrv.c > @@ -85,8 +85,7 @@ static void dw_i2c_acpi_params(struct > platform_device *pdev, char method[], > > *hcnt = (u16)objs[0].integer.value; > *lcnt = (u16)objs[1].integer.value; > - if (sda_hold) > - *sda_hold = (u32)objs[2].integer.value; > + *sda_hold = (u32)objs[2].integer.value; > } > > kfree(buf.pointer); > @@ -105,14 +104,28 @@ static int dw_i2c_acpi_configure(struct > platform_device *pdev) > dev->rx_fifo_depth = 32; > > /* > - * Try to get SDA hold time and *CNT values from an ACPI > method if > - * it exists for both supported speed modes. > + * Try to get SDA hold time and *CNT values from an ACPI > method for > + * selected speed modes. > */ > - dw_i2c_acpi_params(pdev, "SSCN", &dev->ss_hcnt, &dev- > >ss_lcnt, NULL); > - dw_i2c_acpi_params(pdev, "FMCN", &dev->fs_hcnt, &dev- > >fs_lcnt, > - &dev->sda_hold_time); > - dw_i2c_acpi_params(pdev, "FPCN", &dev->fp_hcnt, &dev- > >fp_lcnt, NULL); > - dw_i2c_acpi_params(pdev, "HSCN", &dev->hs_hcnt, &dev- > >hs_lcnt, NULL); > + switch (dev->clk_freq) { > + case 100000: > + dw_i2c_acpi_params(pdev, "SSCN", &dev->ss_hcnt, &dev- > >ss_lcnt, > + &dev->sda_hold_time); > + break; > + case 1000000: > + dw_i2c_acpi_params(pdev, "FPCN", &dev->fp_hcnt, &dev- > >fp_lcnt, > + &dev->sda_hold_time); > + break; > + case 3400000: > + dw_i2c_acpi_params(pdev, "HSCN", &dev->hs_hcnt, &dev- > >hs_lcnt, > + &dev->sda_hold_time); > + break; > + case 400000: > + default: > + dw_i2c_acpi_params(pdev, "FMCN", &dev->fs_hcnt, &dev- > >fs_lcnt, > + &dev->sda_hold_time); > + break; > + } > > id = acpi_match_device(pdev->dev.driver->acpi_match_table, > &pdev->dev); > if (id && id->driver_data) -- Andy Shevchenko <[email protected]> Intel Finland Oy
