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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@pengutronix.de>
[ukleinek: split off from a patch that also implemented .get_state()]
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Fixes: 7edf736920 ("pwm: Add driver for STM32 plaftorm")
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Philipp Zabel 2023-10-19 22:07:04 +02:00 committed by Greg Kroah-Hartman
parent 0d554b420c
commit 40fe0903fa
1 changed files with 14 additions and 4 deletions
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18
drivers/pwm/pwm-stm32.c
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@ -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)