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pwm: stm32: Fix enable count for clk in .probe()

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[ Upstream commit 19f1016ea9 ]

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 888a98a4ee
commit 1bf9292164
1 changed files with 14 additions and 4 deletions
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18
drivers/pwm/pwm-stm32.c
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@@ -578,17 +578,21 @@ static void stm32_pwm_detect_complementary(struct stm32_pwm *priv)
priv->have_complementary_output = (ccer != 0); 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 * If channels enable bits don't exist writing 1 will have no
* effect so we can detect and count them. * 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_set_bits(priv->regmap, TIM_CCER, TIM_CCER_CCXE);
regmap_read(priv->regmap, TIM_CCER, &ccer); 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); return hweight32(ccer & TIM_CCER_CCXE);
} }
@@ -599,6 +603,8 @@ static int stm32_pwm_probe(struct platform_device *pdev)
struct device_node *np = dev->of_node; struct device_node *np = dev->of_node;
struct stm32_timers *ddata = dev_get_drvdata(pdev->dev.parent); struct stm32_timers *ddata = dev_get_drvdata(pdev->dev.parent);
struct stm32_pwm *priv; struct stm32_pwm *priv;
unsigned int num_enabled;
unsigned int i;
int ret; int ret;
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
@@ -621,7 +627,11 @@ static int stm32_pwm_probe(struct platform_device *pdev)
priv->chip.dev = dev; priv->chip.dev = dev;
priv->chip.ops = &stm32pwm_ops; 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 = devm_pwmchip_add(dev, &priv->chip); ret = devm_pwmchip_add(dev, &priv->chip);
if (ret < 0) if (ret < 0)