[PATCH 1/2] pwm: lpss: select core part automatically

[PATCH 1/2] pwm: lpss: select core part automatically

[Mika Westerberg]

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

We have two users of core part right now. Let them to select core part
automatically.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/pwm/Kconfig | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 2f4641a0e88b..aef635b7e2d1 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -222,18 +222,12 @@ config PWM_LPC32XX
 	  will be called pwm-lpc32xx.
 
 config PWM_LPSS
-	tristate "Intel LPSS PWM support"
-	depends on X86
-	help
-	  Generic PWM framework driver for Intel Low Power Subsystem PWM
-	  controller.
-
-	  To compile this driver as a module, choose M here: the module
-	  will be called pwm-lpss.
+	tristate
 
 config PWM_LPSS_PCI
 	tristate "Intel LPSS PWM PCI driver"
-	depends on PWM_LPSS && PCI
+	depends on X86 && PCI
+	select PWM_LPSS
 	help
 	  The PCI driver for Intel Low Power Subsystem PWM controller.
 
@@ -242,7 +236,8 @@ config PWM_LPSS_PCI
 
 config PWM_LPSS_PLATFORM
 	tristate "Intel LPSS PWM platform driver"
-	depends on PWM_LPSS && ACPI
+	depends on X86 && ACPI
+	select PWM_LPSS
 	help
 	  The platform driver for Intel Low Power Subsystem PWM controller.
 
-- 
2.6.2

[PATCH 2/2] pwm: lpss: Rework the sequence of programming PWM_SW_UPDATE

[Mika Westerberg]

Setting of PWM_SW_UPDATE is bit different in Intel Broxton compared to the
previous generation SoCs. Previously it was OK to set the bit many times
(from userspace via sysfs for example) before the PWM is actually enabled.

Starting from Intel Broxton it seems that we must set PWM_SW_UPDATE only
once before the PWM is enabled. Otherwise it is possible that the PWM does
not start properly.

Change the sequence of how PWM_SW_UPDATE is programmed so that we only set
it in pwm_lpss_config() when the PWM is already enabled. The initial
setting of PWM_SW_UPDATE will be done when PWM gets enabled. This should
make the driver work with the previous generation Intel SoCs and Broxton.

Add also small delay after the bit is set to let the hardware propagate it
properly.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
Applies on top of Qipeng's patch here:

https://patchwork.ozlabs.org/patch/545313/

 drivers/pwm/pwm-lpss.c | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/drivers/pwm/pwm-lpss.c b/drivers/pwm/pwm-lpss.c
index 320dbf250cc5..6063c3dcbd46 100644
--- a/drivers/pwm/pwm-lpss.c
+++ b/drivers/pwm/pwm-lpss.c
@@ -13,6 +13,7 @@
  * published by the Free Software Foundation.
  */
 
+#include <linux/delay.h>
 #include <linux/io.h>
 #include <linux/time.h>
 #include <linux/kernel.h>
@@ -80,6 +81,13 @@ static inline void pwm_lpss_write(const struct pwm_device *pwm, u32 value)
 	writel(value, lpwm->regs + pwm->hwpwm * PWM_SIZE + PWM);
 }
 
+static void pwm_lpss_update(struct pwm_device *pwm)
+{
+	pwm_lpss_write(pwm, pwm_lpss_read(pwm) | PWM_SW_UPDATE);
+	/* Give it some time to propagate */
+	usleep_range(10, 50);
+}
+
 static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
 			   int duty_ns, int period_ns)
 {
@@ -117,10 +125,15 @@ static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	base_unit &= (base_unit_range - 1);
 	ctrl |= (u32) base_unit << PWM_BASE_UNIT_SHIFT;
 	ctrl |= on_time_div;
-	/* request PWM to update on next cycle */
-	ctrl |= PWM_SW_UPDATE;
 	pwm_lpss_write(pwm, ctrl);
 
+	/*
+	 * If the PWM is already enabled we need to notify the hardware
+	 * about the change by setting PWM_SW_UPDATE.
+	 */
+	if (pwm_is_enabled(pwm))
+		pwm_lpss_update(pwm);
+
 	pm_runtime_put(chip->dev);
 
 	return 0;
@@ -129,6 +142,12 @@ static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
 static int pwm_lpss_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	pm_runtime_get_sync(chip->dev);
+
+	/*
+	 * Hardware must first see PWM_SW_UPDATE before the PWM can be
+	 * enabled.
+	 */
+	pwm_lpss_update(pwm);
 	pwm_lpss_write(pwm, pwm_lpss_read(pwm) | PWM_ENABLE);
 	return 0;
 }
-- 
2.6.2

Re: [PATCH 2/2] pwm: lpss: Rework the sequence of programming PWM_SW_UPDATE

[Thierry Reding]

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On Wed, Nov 18, 2015 at 01:25:18PM +0200, Mika Westerberg wrote:
> Setting of PWM_SW_UPDATE is bit different in Intel Broxton compared to the
> previous generation SoCs. Previously it was OK to set the bit many times
> (from userspace via sysfs for example) before the PWM is actually enabled.
> 
> Starting from Intel Broxton it seems that we must set PWM_SW_UPDATE only
> once before the PWM is enabled. Otherwise it is possible that the PWM does
> not start properly.
> 
> Change the sequence of how PWM_SW_UPDATE is programmed so that we only set
> it in pwm_lpss_config() when the PWM is already enabled. The initial
> setting of PWM_SW_UPDATE will be done when PWM gets enabled. This should
> make the driver work with the previous generation Intel SoCs and Broxton.
> 
> Add also small delay after the bit is set to let the hardware propagate it
> properly.
> 
> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> ---
> Applies on top of Qipeng's patch here:
> 
> https://patchwork.ozlabs.org/patch/545313/
> 
>  drivers/pwm/pwm-lpss.c | 23 +++++++++++++++++++++--
>  1 file changed, 21 insertions(+), 2 deletions(-)

Applied, thanks.

Thierry

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Re: [PATCH 1/2] pwm: lpss: select core part automatically

[Mika Westerberg]

Ping?

On Wed, Nov 18, 2015 at 01:25:17PM +0200, Mika Westerberg wrote:
> From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> 
> We have two users of core part right now. Let them to select core part
> automatically.
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> ---
>  drivers/pwm/Kconfig | 15 +++++----------
>  1 file changed, 5 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
> index 2f4641a0e88b..aef635b7e2d1 100644
> --- a/drivers/pwm/Kconfig
> +++ b/drivers/pwm/Kconfig
> @@ -222,18 +222,12 @@ config PWM_LPC32XX
>  	  will be called pwm-lpc32xx.
>  
>  config PWM_LPSS
> -	tristate "Intel LPSS PWM support"
> -	depends on X86
> -	help
> -	  Generic PWM framework driver for Intel Low Power Subsystem PWM
> -	  controller.
> -
> -	  To compile this driver as a module, choose M here: the module
> -	  will be called pwm-lpss.
> +	tristate
>  
>  config PWM_LPSS_PCI
>  	tristate "Intel LPSS PWM PCI driver"
> -	depends on PWM_LPSS && PCI
> +	depends on X86 && PCI
> +	select PWM_LPSS
>  	help
>  	  The PCI driver for Intel Low Power Subsystem PWM controller.
>  
> @@ -242,7 +236,8 @@ config PWM_LPSS_PCI
>  
>  config PWM_LPSS_PLATFORM
>  	tristate "Intel LPSS PWM platform driver"
> -	depends on PWM_LPSS && ACPI
> +	depends on X86 && ACPI
> +	select PWM_LPSS
>  	help
>  	  The platform driver for Intel Low Power Subsystem PWM controller.
>  
> -- 
> 2.6.2

Re: [PATCH 1/2] pwm: lpss: select core part automatically

[Thierry Reding]

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On Wed, Nov 18, 2015 at 01:25:17PM +0200, Mika Westerberg wrote:
> From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> 
> We have two users of core part right now. Let them to select core part
> automatically.
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> ---
>  drivers/pwm/Kconfig | 15 +++++----------
>  1 file changed, 5 insertions(+), 10 deletions(-)

Applied, thanks.

Thierry

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