linux-kernel - [PATCH v2] mfd: intel_soc_pmic_crc: Use PWM_LOOKUP_WITH

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Message-ID: <20240527114743.326482-1-hdegoede@redhat.com>
Date: Mon, 27 May 2024 13:47:43 +0200
From: Hans de Goede <hdegoede@...hat.com>
To: Andy Shevchenko <andy@...nel.org>,
	Lee Jones <lee.jones@...aro.org>
Cc: Hans de Goede <hdegoede@...hat.com>,
	Jani Nikula <jani.nikula@...el.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2] mfd: intel_soc_pmic_crc: Use PWM_LOOKUP_WITH_MODULE() for the PWM lookup

The primary use of the CRC PMIC's PWM is for LCD panel backlight
control by the i915 driver.

Due to its complexity the probe() function of the i915 driver does not
support -EPROBE_DEFER handling. So far the pwm-crc driver must be built
into the kernel to ensure that the pwm_get() done by the i915 driver
succeeds at once (rather then returning -EPROBE_DEFER).

But the PWM core can load the module from pwm_get() if a module-name is
provided in the pwm_lookup associated with the consumer device.

Switch to using PWM_LOOKUP_WITH_MODULE() for the lookup added for
the Intel integrated GPU, so that the PWM core can load the module from
pwm_get() as needed allowing the pwm-crc driver to be safely built as
module.

This has been successfully tested on an Asus T100TAM with pwm-crc
build as a module.

Link: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/11081
Reviewed-by: Andy Shevchenko <andy@...nel.org>
Signed-off-by: Hans de Goede <hdegoede@...hat.com>
---
Changes in v2:
- Some small commit message tweaks
- Add Andy's Reviewed-by
---
 drivers/mfd/intel_soc_pmic_crc.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/mfd/intel_soc_pmic_crc.c b/drivers/mfd/intel_soc_pmic_crc.c
index 581f81cbaa24..876d017f74fe 100644
--- a/drivers/mfd/intel_soc_pmic_crc.c
+++ b/drivers/mfd/intel_soc_pmic_crc.c
@@ -137,7 +137,9 @@ static const struct regmap_irq_chip crystal_cove_irq_chip = {

 /* PWM consumed by the Intel GFX */
 static struct pwm_lookup crc_pwm_lookup[] = {
-	PWM_LOOKUP("crystal_cove_pwm", 0, "0000:00:02.0", "pwm_pmic_backlight", 0, PWM_POLARITY_NORMAL),
+	PWM_LOOKUP_WITH_MODULE("crystal_cove_pwm", 0, "0000:00:02.0",
+			       "pwm_pmic_backlight", 0, PWM_POLARITY_NORMAL,
+			       "pwm-crc"),
 };

 struct crystal_cove_config {
-- 
2.45.1