On Fri, 17 Apr 2015, Charles Keepax wrote: > The wm5102 uses a custom boot sequence and the standard boot sequence is > disabled. However, the standard boot sequence must be run at least once > after a cold boot (caused by either a hard reset or removal of AVDD). > Unfortunately the register WRITE_SEQUENCER_CTRL_3 is not affected by the > hardware reset. This means if the device has been previously booted but > the AVDD supply has never been removed, arizona_dev_init will reset the > chip but the boot sequence will not run, which can cause numerous > problems. The solution is to manually clear this register and then boot > the chip again, which is what this patch does. > > Signed-off-by: Charles Keepax <[email protected]> > --- > drivers/mfd/arizona-core.c | 50 +++++++++++++++++++++++++++++++++++-------- > 1 files changed, 40 insertions(+), 10 deletions(-)
Hacks galore! Acked-by: Lee Jones <[email protected]> > diff --git a/drivers/mfd/arizona-core.c b/drivers/mfd/arizona-core.c > index c0e8a96..73418bd 100644 > --- a/drivers/mfd/arizona-core.c > +++ b/drivers/mfd/arizona-core.c > @@ -344,6 +344,33 @@ err_fll: > return err; > } > > +static int wm5102_clear_write_sequencer(struct arizona *arizona) > +{ > + int ret; > + > + ret = regmap_write(arizona->regmap, ARIZONA_WRITE_SEQUENCER_CTRL_3, > + 0x0); > + if (ret) { > + dev_err(arizona->dev, > + "Failed to clear write sequencer state: %d\n", ret); > + return ret; > + } > + > + arizona_enable_reset(arizona); > + regulator_disable(arizona->dcvdd); > + > + msleep(20); > + > + ret = regulator_enable(arizona->dcvdd); > + if (ret) { > + dev_err(arizona->dev, "Failed to re-enable DCVDD: %d\n", ret); > + return ret; > + } > + arizona_disable_reset(arizona); > + > + return 0; > +} > + > #ifdef CONFIG_PM > static int arizona_runtime_resume(struct device *dev) > { > @@ -810,21 +837,24 @@ int arizona_dev_init(struct arizona *arizona) > case WM5102: > ret = regmap_read(arizona->regmap, > ARIZONA_WRITE_SEQUENCER_CTRL_3, &val); > - if (ret != 0) > + if (ret) { > dev_err(dev, > "Failed to check write sequencer state: %d\n", > ret); > - else if (val & 0x01) > - break; > - /* Fall through */ > - default: > - ret = arizona_wait_for_boot(arizona); > - if (ret != 0) { > - dev_err(arizona->dev, > - "Device failed initial boot: %d\n", ret); > - goto err_reset; > + } else if (val & 0x01) { > + ret = wm5102_clear_write_sequencer(arizona); > + if (ret) > + return ret; > } > break; > + default: > + break; > + } > + > + ret = arizona_wait_for_boot(arizona); > + if (ret) { > + dev_err(arizona->dev, "Device failed initial boot: %d\n", ret); > + goto err_reset; > } > > /* Read the device ID information & do device specific stuff */ -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
