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pwm: Fix an off-by-one in the stm32 driver

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Hardware engineers tend to start counting at 1 while the software guys
 usually start with 0. This isn't so nice because that results in drivers
 where pwm device #2 needs to use the hardware registers with index 3.
 
 With the commits
 
 	796b942f65 ("mfd: stm32-timers: Add some register definitions with a parameter")
 	7cea05ae1d ("pwm-stm32: Make use of parametrised register definitions")
 
 (merged for v6.11-rc1) I tried to improve the situation and make this
 counting mismatch more explicit and transparent. However in one instance
 I failed to add the needed +1.
 
 This was noticed by Fabrice Gasnier (however in a way that made me
 hesitate to add a "Reported-by:" tag, see
 https://lore.kernel.org/linux-pwm/3515a8f3-436e-4d14-9bac-dfe6aa869819@foss.st.com),
 thanks to him for catching the issue.
 
 A small patch fixing that mismatch is the only change included here.
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Merge tag 'pwm/for-6.11-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/ukleinek/linux

Pull pwm fix from Uwe Kleine-König:
 "Fix an off-by-one in the stm32 driver.

  Hardware engineers tend to start counting at 1 while the software guys
  usually start with 0. This isn't so nice because that results in
  drivers where pwm device #2 needs to use the hardware registers with
  index 3.

  This was noticed by Fabrice Gasnier.

  A small patch fixing that mismatch is the only change included here"

* tag 'pwm/for-6.11-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/ukleinek/linux:
  pwm: stm32: Use the right CCxNP bit in stm32_pwm_enable()
This commit is contained in:
Linus Torvalds 2024-09-06 11:28:14 -07:00
commit 8654fa5ca3
1 changed files with 1 additions and 1 deletions
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2
drivers/pwm/pwm-stm32.c
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@ -412,7 +412,7 @@ static int stm32_pwm_enable(struct stm32_pwm *priv, unsigned int ch)
/* Enable channel */
mask = TIM_CCER_CCxE(ch + 1);
if (priv->have_complementary_output)
mask |= TIM_CCER_CCxNE(ch);
mask |= TIM_CCER_CCxNE(ch + 1);
regmap_set_bits(priv->regmap, TIM_CCER, mask);