Messages in this thread Patch in this message | | | From | Mark Brown <> | Subject | [PATCH 6/9] mfd: Read wm831x AUXADC conversion results before acknowledging interrupt | Date | Thu, 2 Jun 2011 19:18:52 +0100 |
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Ensure that there's no possibility of loosing an AUXADC interrupt by reading the conversion result in the IRQ handler when using interrupts. Otherwise it's possible that under very heavy load a new conversion could be initiated before the acknowledgement for a previous interrupt has happened.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> --- drivers/mfd/wm831x-core.c | 47 +++++++++++++++++++++++++------------- include/linux/mfd/wm831x/core.h | 1 + 2 files changed, 32 insertions(+), 16 deletions(-)
diff --git a/drivers/mfd/wm831x-core.c b/drivers/mfd/wm831x-core.c index 58f033b..480abc1 100644 --- a/drivers/mfd/wm831x-core.c +++ b/drivers/mfd/wm831x-core.c @@ -376,6 +376,16 @@ int wm831x_auxadc_read(struct wm831x *wm831x, enum wm831x_auxadc input) goto disable; } } + + ret = wm831x_reg_read(wm831x, WM831X_AUXADC_DATA); + if (ret < 0) { + dev_err(wm831x->dev, + "Failed to read AUXADC data: %d\n", ret); + goto disable; + } + + wm831x->auxadc_data = ret; + } else { /* If we are using interrupts then wait for the * interrupt to complete. Use an extremely long @@ -390,23 +400,18 @@ int wm831x_auxadc_read(struct wm831x *wm831x, enum wm831x_auxadc input) } } - ret = wm831x_reg_read(wm831x, WM831X_AUXADC_DATA); - if (ret < 0) { - dev_err(wm831x->dev, "Failed to read AUXADC data: %d\n", ret); + src = ((wm831x->auxadc_data & WM831X_AUX_DATA_SRC_MASK) + >> WM831X_AUX_DATA_SRC_SHIFT) - 1; + + if (src == 14) + src = WM831X_AUX_CAL; + + if (src != input) { + dev_err(wm831x->dev, "Data from source %d not %d\n", + src, input); + ret = -EINVAL; } else { - src = ((ret & WM831X_AUX_DATA_SRC_MASK) - >> WM831X_AUX_DATA_SRC_SHIFT) - 1; - - if (src == 14) - src = WM831X_AUX_CAL; - - if (src != input) { - dev_err(wm831x->dev, "Data from source %d not %d\n", - src, input); - ret = -EINVAL; - } else { - ret &= WM831X_AUX_DATA_MASK; - } + ret = wm831x->auxadc_data & WM831X_AUX_DATA_MASK; } disable: @@ -420,6 +425,16 @@ EXPORT_SYMBOL_GPL(wm831x_auxadc_read); static irqreturn_t wm831x_auxadc_irq(int irq, void *irq_data) { struct wm831x *wm831x = irq_data; + int ret; + + ret = wm831x_reg_read(wm831x, WM831X_AUXADC_DATA); + if (ret < 0) { + dev_err(wm831x->dev, + "Failed to read AUXADC data: %d\n", ret); + wm831x->auxadc_data = 0xffff; + } else { + wm831x->auxadc_data = ret; + } complete(&wm831x->auxadc_done); diff --git a/include/linux/mfd/wm831x/core.h b/include/linux/mfd/wm831x/core.h index 9564cf3..592e4fd 100644 --- a/include/linux/mfd/wm831x/core.h +++ b/include/linux/mfd/wm831x/core.h @@ -278,6 +278,7 @@ struct wm831x { struct mutex auxadc_lock; struct completion auxadc_done; + u16 auxadc_data; /* The WM831x has a security key blocking access to certain * registers. The mutex is taken by the accessors for locking -- 1.7.5.3
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