Re: [PATCH v2 3/9] mfd: wm5102: Ensure we always boot the device fully

Lee Jones
2015-04-29T12:25:40Z

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 <ckeepax@opensource.wolfsonmicro.com>
> ---
> drivers/mfd/arizona-core.c | 50 +++++++++++++++++++++++++++++++++++--------
> 1 files changed, 40 insertions(+), 10 deletions(-)

Hacks galore!

Acked-by: Lee Jones <lee.jones@linaro.org>

> 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
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