On Fri, 02 Dec 2016, Hans de Goede hdegoede@redhat.com wrote:
The primary consumer of the lpss pwm is the i915 kms driver, but currently that driver cannot get the pwm because i915 platforms are not using devicetree and pwm-lpss does not call pwm_add_table.
Another problem is that i915 does not support get_pwm returning -EPROBE_DEFER and i915's init is very complex and this is almost impossible to fix.
This commit changes the PWM_LPSS Kconfig from a tristate to a bool, so that when the i915 driver loads the lpss pwm will be available avoiding the -EPROBE_DEFER issue. Note that this is identical to how the same problem was solved for the pwm-crc driver.
Arguably this solution was worse for pwm-crc than pwm-lpss here, because bool CONFIG_PWM_CRC depends on INTEL_SOC_PMIC which depends on I2C being built-in. This one doesn't have all that bad dependencies.
FWIW, both patches are
Acked-by: Jani Nikula jani.nikula@intel.com
Being builtin also allows calling pwm_add_table directly from the pwm-lpss code, otherwise the pwm_add_table call would need to be put somewhere else to ensure it happens before i915 calls pwm_get, even if i915 would support -EPROBE_DEFER.
Signed-off-by: Hans de Goede hdegoede@redhat.com
drivers/pwm/Kconfig | 12 +++--------- drivers/pwm/pwm-lpss.c | 11 +++++++++++ 2 files changed, 14 insertions(+), 9 deletions(-)
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index bf01288..cda31ea 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -240,28 +240,22 @@ config PWM_LPC32XX will be called pwm-lpc32xx.
config PWM_LPSS
- tristate
- bool
config PWM_LPSS_PCI
- tristate "Intel LPSS PWM PCI driver"
- bool "Intel LPSS PWM PCI driver" depends on X86 && PCI select PWM_LPSS help The PCI driver for Intel Low Power Subsystem PWM controller.
To compile this driver as a module, choose M here: the modulewill be called pwm-lpss-pci.config PWM_LPSS_PLATFORM
- tristate "Intel LPSS PWM platform driver"
- bool "Intel LPSS PWM platform driver" depends on X86 && ACPI select PWM_LPSS help The platform driver for Intel Low Power Subsystem PWM controller.
To compile this driver as a module, choose M here: the modulewill be called pwm-lpss-platform.config PWM_MESON tristate "Amlogic Meson PWM driver" depends on ARCH_MESON diff --git a/drivers/pwm/pwm-lpss.c b/drivers/pwm/pwm-lpss.c index 72c0bce..b4d8835 100644 --- a/drivers/pwm/pwm-lpss.c +++ b/drivers/pwm/pwm-lpss.c @@ -161,6 +161,12 @@ static const struct pwm_ops pwm_lpss_ops = { .owner = THIS_MODULE, };
+/* PWM consumed by the Intel GFX */ +static struct pwm_lookup pwm_lpss_lookup[] = {
- PWM_LOOKUP("pwm-lpss", 0, "0000:00:02.0", "pwm_backlight", 0,
PWM_POLARITY_NORMAL),+};
struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev, struct resource *r, const struct pwm_lpss_boardinfo *info) { @@ -193,12 +199,17 @@ struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev, struct resource *r, return ERR_PTR(ret); }
- /* Add lookup table for pwm_backlight */
- pwm_lpss_lookup[0].provider = dev_name(dev);
- pwm_add_table(pwm_lpss_lookup, ARRAY_SIZE(pwm_lpss_lookup));
- return lpwm;
} EXPORT_SYMBOL_GPL(pwm_lpss_probe);
int pwm_lpss_remove(struct pwm_lpss_chip *lpwm) {
- pwm_remove_table(pwm_lpss_lookup, ARRAY_SIZE(pwm_lpss_lookup)); return pwmchip_remove(&lpwm->chip);
} EXPORT_SYMBOL_GPL(pwm_lpss_remove);