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Subject[PATCHv2 2/2] gpio: mvebu: fix gpio bank registration when pwm is used
Date
If more than one gpio bank has the "pwm" property, only one will be
registered successfully, all the others will fail with:
mvebu-gpio: probe of f1018140.gpio failed with error -17

That's because in alloc_pwms(), the chip->base (aka "int pwm"), was not
set (thus, ==0) ; and 0 is a meaningful start value in alloc_pwm().
What was intended is mvpwm->chip->base = -1.
Like that, the numbering will be done auto-magically

Moreover, as the region might be already occupied by another pwm, we
shouldn't force:
mvpwm->chip->base = 0
nor
mvpwm->chip->base = id * MVEBU_MAX_GPIO_PER_BANK;

Tested on clearfog-pro (Marvell 88F6828)

Fixes: 757642f9a584 ("gpio: mvebu: Add limited PWM support")
Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
---
drivers/gpio/gpio-mvebu.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/gpio/gpio-mvebu.c b/drivers/gpio/gpio-mvebu.c
index cdef2c78cb3b..5104b6398139 100644
--- a/drivers/gpio/gpio-mvebu.c
+++ b/drivers/gpio/gpio-mvebu.c
@@ -768,6 +768,13 @@ static int mvebu_pwm_probe(struct platform_device *pdev,
mvpwm->chip.dev = dev;
mvpwm->chip.ops = &mvebu_pwm_ops;
mvpwm->chip.npwm = mvchip->chip.ngpio;
+ /*
+ * There may already be some PWM allocated, so we can't force
+ * mvpwm->chip.base to a fixed point like mvchip->chip.base.
+ * So, we let pwmchip_add() do the numbering and take the next free
+ * region.
+ */
+ mvpwm->chip.base = -1;

spin_lock_init(&mvpwm->lock);

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