This is a note to let you know that I've just added the patch titled
pwm: stm32: Fix enable count for clk in .probe()
to the 5.15-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:
pwm-stm32-fix-enable-count-for-clk-in-.probe.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit b96c53531c6f9d0c2e6f70162c84c7d1e5fc0246
Author: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
Date: Thu Oct 19 22:07:04 2023 +0200
pwm: stm32: Fix enable count for clk in .probe()
[ Upstream commit 19f1016ea9600ed89bc24247c36ff5934ad94fbb ]
Make the driver take over hardware state without disabling in .probe()
and enable the clock for each enabled channel.
Signed-off-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
[ukleinek: split off from a patch that also implemented .get_state()]
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
Fixes: 7edf7369205b ("pwm: Add driver for STM32 plaftorm")
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@xxxxxxxxxxx>
Signed-off-by: Thierry Reding <thierry.reding@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/pwm/pwm-stm32.c b/drivers/pwm/pwm-stm32.c
index 9c260aac442d..bdcdb7f38312 100644
--- a/drivers/pwm/pwm-stm32.c
+++ b/drivers/pwm/pwm-stm32.c
@@ -575,17 +575,21 @@ static void stm32_pwm_detect_complementary(struct stm32_pwm *priv)
priv->have_complementary_output = (ccer != 0);
}
-static unsigned int stm32_pwm_detect_channels(struct stm32_pwm *priv)
+static unsigned int stm32_pwm_detect_channels(struct stm32_pwm *priv,
+ unsigned int *num_enabled)
{
- u32 ccer;
+ u32 ccer, ccer_backup;
/*
* If channels enable bits don't exist writing 1 will have no
* effect so we can detect and count them.
*/
+ regmap_read(priv->regmap, TIM_CCER, &ccer_backup);
regmap_set_bits(priv->regmap, TIM_CCER, TIM_CCER_CCXE);
regmap_read(priv->regmap, TIM_CCER, &ccer);
- regmap_clear_bits(priv->regmap, TIM_CCER, TIM_CCER_CCXE);
+ regmap_write(priv->regmap, TIM_CCER, ccer_backup);
+
+ *num_enabled = hweight32(ccer_backup & TIM_CCER_CCXE);
return hweight32(ccer & TIM_CCER_CCXE);
}
@@ -596,6 +600,8 @@ static int stm32_pwm_probe(struct platform_device *pdev)
struct device_node *np = dev->of_node;
struct stm32_timers *ddata = dev_get_drvdata(pdev->dev.parent);
struct stm32_pwm *priv;
+ unsigned int num_enabled;
+ unsigned int i;
int ret;
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
@@ -618,7 +624,11 @@ static int stm32_pwm_probe(struct platform_device *pdev)
priv->chip.dev = dev;
priv->chip.ops = &stm32pwm_ops;
- priv->chip.npwm = stm32_pwm_detect_channels(priv);
+ priv->chip.npwm = stm32_pwm_detect_channels(priv, &num_enabled);
+
+ /* Initialize clock refcount to number of enabled PWM channels. */
+ for (i = 0; i < num_enabled; i++)
+ clk_enable(priv->clk);
ret = pwmchip_add(&priv->chip);
if (ret < 0)
