[PATCH] pwm: lpss: remove dependency on clk framework

[PATCH] pwm: lpss: remove dependency on clk framework

[Heikki Krogerus]

Unlike other Intel LPSS devices, the PWM does not have the
clock dividers or the gate. All we get from the clock is the
rate. Since PCI case uses the driver data to get the rate,
we can drop the clk and use the same data also in case of
ACPI. The frequency is the same.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 drivers/pwm/pwm-lpss.c | 32 ++++++++++----------------------
 1 file changed, 10 insertions(+), 22 deletions(-)

diff --git a/drivers/pwm/pwm-lpss.c b/drivers/pwm/pwm-lpss.c
index 44ce6c6..4df994f 100644
--- a/drivers/pwm/pwm-lpss.c
+++ b/drivers/pwm/pwm-lpss.c
@@ -14,7 +14,6 @@
  */
 
 #include <linux/acpi.h>
-#include <linux/clk.h>
 #include <linux/device.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -37,7 +36,6 @@ static int pci_drv, plat_drv;	/* So we know which drivers registered */
 struct pwm_lpss_chip {
 	struct pwm_chip chip;
 	void __iomem *regs;
-	struct clk *clk;
 	unsigned long clk_rate;
 };
 
@@ -97,11 +95,6 @@ static int pwm_lpss_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct pwm_lpss_chip *lpwm = to_lpwm(chip);
 	u32 ctrl;
-	int ret;
-
-	ret = clk_prepare_enable(lpwm->clk);
-	if (ret)
-		return ret;
 
 	ctrl = readl(lpwm->regs + PWM);
 	writel(ctrl | PWM_ENABLE, lpwm->regs + PWM);
@@ -116,8 +109,6 @@ static void pwm_lpss_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 
 	ctrl = readl(lpwm->regs + PWM);
 	writel(ctrl & ~PWM_ENABLE, lpwm->regs + PWM);
-
-	clk_disable_unprepare(lpwm->clk);
 }
 
 static const struct pwm_ops pwm_lpss_ops = {
@@ -142,17 +133,7 @@ static struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev,
 	if (IS_ERR(lpwm->regs))
 		return ERR_CAST(lpwm->regs);
 
-	if (info) {
-		lpwm->clk_rate = info->clk_rate;
-	} else {
-		lpwm->clk = devm_clk_get(dev, NULL);
-		if (IS_ERR(lpwm->clk)) {
-			dev_err(dev, "failed to get PWM clock\n");
-			return ERR_CAST(lpwm->clk);
-		}
-		lpwm->clk_rate = clk_get_rate(lpwm->clk);
-	}
-
+	lpwm->clk_rate = info->clk_rate;
 	lpwm->chip.dev = dev;
 	lpwm->chip.ops = &pwm_lpss_ops;
 	lpwm->chip.base = -1;
@@ -221,12 +202,19 @@ static struct pci_driver pwm_lpss_driver_pci = {
 
 static int pwm_lpss_probe_platform(struct platform_device *pdev)
 {
+	const struct pwm_lpss_boardinfo *info;
+	const struct acpi_device_id *id;
 	struct pwm_lpss_chip *lpwm;
 	struct resource *r;
 
+	id = acpi_match_device(pdev->dev.driver->acpi_match_table, &pdev->dev);
+	if (!id)
+		return -ENODEV;
+
 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 
-	lpwm = pwm_lpss_probe(&pdev->dev, r, NULL);
+	info = (struct pwm_lpss_boardinfo *)id->driver_data;
+	lpwm = pwm_lpss_probe(&pdev->dev, r, info);
 	if (IS_ERR(lpwm))
 		return PTR_ERR(lpwm);
 
@@ -242,7 +230,7 @@ static int pwm_lpss_remove_platform(struct platform_device *pdev)
 }
 
 static const struct acpi_device_id pwm_lpss_acpi_match[] = {
-	{ "80860F09", 0 },
+	{ "80860F09", (unsigned long)&byt_info },
 	{ },
 };
 MODULE_DEVICE_TABLE(acpi, pwm_lpss_acpi_match);
-- 
2.0.0.rc2

Re: [PATCH] pwm: lpss: remove dependency on clk framework

[Mika Westerberg]

On Fri, May 09, 2014 at 11:35:21AM +0300, Heikki Krogerus wrote:
> Unlike other Intel LPSS devices, the PWM does not have the
> clock dividers or the gate. All we get from the clock is the
> rate. Since PCI case uses the driver data to get the rate,
> we can drop the clk and use the same data also in case of
> ACPI. The frequency is the same.
> 
> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

No objections from me,

Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>

RE: [PATCH] pwm: lpss: remove dependency on clk framework

[Chew, Chiau Ee]

> Unlike other Intel LPSS devices, the PWM does not have the clock dividers or
> the gate. All we get from the clock is the rate. Since PCI case uses the driver
> data to get the rate, we can drop the clk and use the same data also in case of
> ACPI. The frequency is the same.
> 
> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> ---
>  drivers/pwm/pwm-lpss.c | 32 ++++++++++----------------------
>  1 file changed, 10 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/pwm/pwm-lpss.c b/drivers/pwm/pwm-lpss.c index
> 44ce6c6..4df994f 100644
> --- a/drivers/pwm/pwm-lpss.c
> +++ b/drivers/pwm/pwm-lpss.c
> @@ -14,7 +14,6 @@
>   */
> 
>  #include <linux/acpi.h>
> -#include <linux/clk.h>
>  #include <linux/device.h>
>  #include <linux/kernel.h>
>  #include <linux/module.h>
> @@ -37,7 +36,6 @@ static int pci_drv, plat_drv;	/* So we know which drivers
> registered */
>  struct pwm_lpss_chip {
>  	struct pwm_chip chip;
>  	void __iomem *regs;
> -	struct clk *clk;
>  	unsigned long clk_rate;
>  };
> 
> @@ -97,11 +95,6 @@ static int pwm_lpss_enable(struct pwm_chip *chip,
> struct pwm_device *pwm)  {
>  	struct pwm_lpss_chip *lpwm = to_lpwm(chip);
>  	u32 ctrl;
> -	int ret;
> -
> -	ret = clk_prepare_enable(lpwm->clk);
> -	if (ret)
> -		return ret;
> 
>  	ctrl = readl(lpwm->regs + PWM);
>  	writel(ctrl | PWM_ENABLE, lpwm->regs + PWM); @@ -116,8 +109,6
> @@ static void pwm_lpss_disable(struct pwm_chip *chip, struct pwm_device
> *pwm)
> 
>  	ctrl = readl(lpwm->regs + PWM);
>  	writel(ctrl & ~PWM_ENABLE, lpwm->regs + PWM);
> -
> -	clk_disable_unprepare(lpwm->clk);
>  }
> 
>  static const struct pwm_ops pwm_lpss_ops = { @@ -142,17 +133,7 @@ static
> struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev,
>  	if (IS_ERR(lpwm->regs))
>  		return ERR_CAST(lpwm->regs);
> 
> -	if (info) {
> -		lpwm->clk_rate = info->clk_rate;
> -	} else {
> -		lpwm->clk = devm_clk_get(dev, NULL);
> -		if (IS_ERR(lpwm->clk)) {
> -			dev_err(dev, "failed to get PWM clock\n");
> -			return ERR_CAST(lpwm->clk);
> -		}
> -		lpwm->clk_rate = clk_get_rate(lpwm->clk);
> -	}
> -
> +	lpwm->clk_rate = info->clk_rate;
>  	lpwm->chip.dev = dev;
>  	lpwm->chip.ops = &pwm_lpss_ops;
>  	lpwm->chip.base = -1;
> @@ -221,12 +202,19 @@ static struct pci_driver pwm_lpss_driver_pci = {
> 
>  static int pwm_lpss_probe_platform(struct platform_device *pdev)  {
> +	const struct pwm_lpss_boardinfo *info;
> +	const struct acpi_device_id *id;
>  	struct pwm_lpss_chip *lpwm;
>  	struct resource *r;
> 
> +	id = acpi_match_device(pdev->dev.driver->acpi_match_table, &pdev-
> >dev);
> +	if (!id)
> +		return -ENODEV;
> +
>  	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> 
> -	lpwm = pwm_lpss_probe(&pdev->dev, r, NULL);
> +	info = (struct pwm_lpss_boardinfo *)id->driver_data;
> +	lpwm = pwm_lpss_probe(&pdev->dev, r, info);
>  	if (IS_ERR(lpwm))
>  		return PTR_ERR(lpwm);
> 
> @@ -242,7 +230,7 @@ static int pwm_lpss_remove_platform(struct
> platform_device *pdev)  }
> 
>  static const struct acpi_device_id pwm_lpss_acpi_match[] = {
> -	{ "80860F09", 0 },
> +	{ "80860F09", (unsigned long)&byt_info },
>  	{ },
>  };

Heikki,
For ACPI mode, the clock rate information for PWM is being setup in the acpi_lpss.c layer.
Thus, only PCI mode depends on the driver_data to pass in the clock rate information.


>  MODULE_DEVICE_TABLE(acpi, pwm_lpss_acpi_match);
> --
> 2.0.0.rc2

Re: [PATCH] pwm: lpss: remove dependency on clk framework

[Heikki Krogerus]

Hi,

On Wed, May 14, 2014 at 07:00:59AM +0000, Chew, Chiau Ee wrote:
> Heikki,
> For ACPI mode, the clock rate information for PWM is being setup in the acpi_lpss.c layer.
> Thus, only PCI mode depends on the driver_data to pass in the clock rate information.

The goal with this patch is actually to free acpi_lpss.c from
delivering the clock for this driver.

The LPSS PWM does not get it's clock from the LPSS 100Mhz source
clock, which means we have to have the rate of it's clock hard-coded.
Since it's already hard coded also in this driver for PCI mode in any
case, it makes no sense to also have it there.

So this patch will allow us to cleanup acpi_lpss.c. We can now remove
the confusing "shared clock" structure where the hard coded rates are
held. This device is the only one that would need it.


Thanks,

-- 
heikki

RE: [PATCH] pwm: lpss: remove dependency on clk framework

[Chew, Chiau Ee]

> 
> Hi,
> 
> On Wed, May 14, 2014 at 07:00:59AM +0000, Chew, Chiau Ee wrote:
> > Heikki,
> > For ACPI mode, the clock rate information for PWM is being setup in the
> acpi_lpss.c layer.
> > Thus, only PCI mode depends on the driver_data to pass in the clock rate
> information.
> 
> The goal with this patch is actually to free acpi_lpss.c from delivering the clock
> for this driver.
> 
> The LPSS PWM does not get it's clock from the LPSS 100Mhz source clock,
> which means we have to have the rate of it's clock hard-coded.
> Since it's already hard coded also in this driver for PCI mode in any case, it
> makes no sense to also have it there.
> 
> So this patch will allow us to cleanup acpi_lpss.c. We can now remove the
> confusing "shared clock" structure where the hard coded rates are held. This
> device is the only one that would need it.
> 

Oh ya...you are right. Sorry about that. I have mixed up the context with other I/O components.

Reviewed-by: Chew, Chiau Ee <chiau.ee.chew@intel.com>

> 
> Thanks,
> 
> --
> heikki

Re: [PATCH] pwm: lpss: remove dependency on clk framework

[Thierry Reding]

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On Fri, May 09, 2014 at 11:35:21AM +0300, Heikki Krogerus wrote:
> Unlike other Intel LPSS devices, the PWM does not have the
> clock dividers or the gate. All we get from the clock is the
> rate. Since PCI case uses the driver data to get the rate,
> we can drop the clk and use the same data also in case of
> ACPI. The frequency is the same.
> 
> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> ---
>  drivers/pwm/pwm-lpss.c | 32 ++++++++++----------------------
>  1 file changed, 10 insertions(+), 22 deletions(-)

Sorry for the long delay. Applied now.

Thierry

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