From: Nuno Sá nuno.sa@analog.com
stable inclusion from stable-5.10.67 commit 4753723f8b48a24acef0afbfb359e0ca17fc328c bugzilla: 182619 https://gitee.com/openeuler/kernel/issues/I4EWO7
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit b76d26d69ecc97ebb24aaf40427a13c808a4f488 upstream.
There is no reason to assume that the IRQ rising edge (indicating that the device start up phase is done) will happen after we request the IRQ. If the device is already up by the time we request it, the call to 'wait_for_completion_timeout()' will timeout and we will fail the device probe even though there's nothing wrong.
Fix it by just polling the status register until we get the indication that the device is up and running. As a side effect of this fix, requesting the IRQ is also moved to after the setup function.
Fixes: f110f3188e563 ("iio: temperature: Add support for LTC2983") Reported-and-tested-by: Drew Fustini drew@pdp7.com Reviewed-by: Drew Fustini drew@pdp7.com Signed-off-by: Nuno Sá nuno.sa@analog.com Reviewed-by: Andy Shevchenko andy.shevchenko@gmail.com Cc: Stable@vger.kernel.org Link: https://lore.kernel.org/r/20210811133220.190264-2-nuno.sa@analog.com Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Chen Jun chenjun102@huawei.com Acked-by: Weilong Chen chenweilong@huawei.com
Signed-off-by: Chen Jun chenjun102@huawei.com --- drivers/iio/temperature/ltc2983.c | 30 ++++++++++++++---------------- 1 file changed, 14 insertions(+), 16 deletions(-)
diff --git a/drivers/iio/temperature/ltc2983.c b/drivers/iio/temperature/ltc2983.c index 3b5ba26d7d86..3b4a0e60e605 100644 --- a/drivers/iio/temperature/ltc2983.c +++ b/drivers/iio/temperature/ltc2983.c @@ -89,6 +89,8 @@
#define LTC2983_STATUS_START_MASK BIT(7) #define LTC2983_STATUS_START(x) FIELD_PREP(LTC2983_STATUS_START_MASK, x) +#define LTC2983_STATUS_UP_MASK GENMASK(7, 6) +#define LTC2983_STATUS_UP(reg) FIELD_GET(LTC2983_STATUS_UP_MASK, reg)
#define LTC2983_STATUS_CHAN_SEL_MASK GENMASK(4, 0) #define LTC2983_STATUS_CHAN_SEL(x) \ @@ -1362,17 +1364,16 @@ static int ltc2983_parse_dt(struct ltc2983_data *st)
static int ltc2983_setup(struct ltc2983_data *st, bool assign_iio) { - u32 iio_chan_t = 0, iio_chan_v = 0, chan, iio_idx = 0; + u32 iio_chan_t = 0, iio_chan_v = 0, chan, iio_idx = 0, status; int ret; - unsigned long time; - - /* make sure the device is up */ - time = wait_for_completion_timeout(&st->completion, - msecs_to_jiffies(250));
- if (!time) { + /* make sure the device is up: start bit (7) is 0 and done bit (6) is 1 */ + ret = regmap_read_poll_timeout(st->regmap, LTC2983_STATUS_REG, status, + LTC2983_STATUS_UP(status) == 1, 25000, + 25000 * 10); + if (ret) { dev_err(&st->spi->dev, "Device startup timed out\n"); - return -ETIMEDOUT; + return ret; }
st->iio_chan = devm_kzalloc(&st->spi->dev, @@ -1492,10 +1493,11 @@ static int ltc2983_probe(struct spi_device *spi) ret = ltc2983_parse_dt(st); if (ret) return ret; - /* - * let's request the irq now so it is used to sync the device - * startup in ltc2983_setup() - */ + + ret = ltc2983_setup(st, true); + if (ret) + return ret; + ret = devm_request_irq(&spi->dev, spi->irq, ltc2983_irq_handler, IRQF_TRIGGER_RISING, name, st); if (ret) { @@ -1503,10 +1505,6 @@ static int ltc2983_probe(struct spi_device *spi) return ret; }
- ret = ltc2983_setup(st, true); - if (ret) - return ret; - indio_dev->name = name; indio_dev->num_channels = st->iio_channels; indio_dev->channels = st->iio_chan;