Patch "iio: adc: meson-saradc: fix the bit_idx of the adc_en clock" has been added to the 4.14-stable tree

Patch "iio: adc: meson-saradc: fix the bit_idx of the adc_en clock" has been added to the 4.14-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    iio: adc: meson-saradc: fix the bit_idx of the adc_en clock

to the 4.14-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     iio-adc-meson-saradc-fix-the-bit_idx-of-the-adc_en-clock.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 7a6b0420d2fe4ce59437bd318826fe468f0d71ae Mon Sep 17 00:00:00 2001
From: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Date: Tue, 31 Oct 2017 21:01:43 +0100
Subject: iio: adc: meson-saradc: fix the bit_idx of the adc_en clock

From: Martin Blumenstingl <martin.blumenstingl@googlemail.com>

commit 7a6b0420d2fe4ce59437bd318826fe468f0d71ae upstream.

Meson8 and Meson8b SoCs use the the SAR ADC gate clock provided by the
MESON_SAR_ADC_REG3 register within the SAR ADC register area.
According to the datasheet (and the existing MESON_SAR_ADC_REG3_CLK_EN
definition) the gate is on bit 30.
The fls() function returns the last set bit, which is "bit index + 1"
(fls(MESON_SAR_ADC_REG3_CLK_EN) returns 31). Fix this by switching to
__ffs() which returns the first set bit, which is bit 30 in our case.

This off by one error results in the ADC not being usable on devices
where the bootloader did not enable the clock.

Fixes: 3adbf3427330 ("iio: adc: add a driver for the SAR ADC found in Amlogic Meson SoCs")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/iio/adc/meson_saradc.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/iio/adc/meson_saradc.c
+++ b/drivers/iio/adc/meson_saradc.c
@@ -600,7 +600,7 @@ static int meson_sar_adc_clk_init(struct
 	init.num_parents = 1;
 
 	priv->clk_gate.reg = base + MESON_SAR_ADC_REG3;
-	priv->clk_gate.bit_idx = fls(MESON_SAR_ADC_REG3_CLK_EN);
+	priv->clk_gate.bit_idx = __ffs(MESON_SAR_ADC_REG3_CLK_EN);
 	priv->clk_gate.hw.init = &init;
 
 	priv->adc_clk = devm_clk_register(&indio_dev->dev, &priv->clk_gate.hw);


Patches currently in stable-queue which might be from martin.blumenstingl@googlemail.com are

queue-4.14/iio-adc-meson-saradc-initialize-the-bandgap-correctly-on-older-socs.patch
queue-4.14/iio-adc-meson-saradc-fix-the-bit_idx-of-the-adc_en-clock.patch
queue-4.14/iio-adc-meson-saradc-meson8-and-meson8b-do-not-have-reg11-and-reg13.patch