* Re: [PATCH] pwm: add lpc32xx pwm support
@ 2012-07-10 6:48 ` Thierry Reding
0 siblings, 0 replies; 6+ messages in thread
From: Thierry Reding @ 2012-07-10 6:48 UTC (permalink / raw)
To: Alexandre Pereira da Silva
Cc: Roland Stigge, Grant Likely, Rob Herring, Rob Landley,
linux-kernel, devicetree-discuss, linux-doc
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On Mon, Jul 09, 2012 at 04:27:54PM -0300, Alexandre Pereira da Silva wrote:
> Add lpc32xx soc pwm driver.
>
> Signed-off-by: Alexandre Pereira da Silva <aletes.xgr@gmail.com>
> ---
> .../devicetree/bindings/pwm/lpc32xx-pwm.txt | 12 ++
> drivers/pwm/Kconfig | 11 ++
> drivers/pwm/Makefile | 1 +
> drivers/pwm/pwm-lpc32xx.c | 151 ++++++++++++++++++++
> 4 files changed, 175 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/pwm/lpc32xx-pwm.txt
> create mode 100644 drivers/pwm/pwm-lpc32xx.c
Hi Alexandre,
overall this looks good, just some comments inline. I'd very much
appreciate an Acked-by from Roland on this.
> diff --git a/Documentation/devicetree/bindings/pwm/lpc32xx-pwm.txt b/Documentation/devicetree/bindings/pwm/lpc32xx-pwm.txt
> new file mode 100644
> index 0000000..fb7b3d5
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pwm/lpc32xx-pwm.txt
> @@ -0,0 +1,12 @@
> +LPC32XX PWM controller
> +
> +Required properties:
> +- compatible: should be "nxp,lpc3220-pwm"
Does the compatible have to be lpc3220-pwm? Can't it be lpc32xx-pwm to
match the driver and binding names?
> +- reg: physical base address and length of the controller's registers
> +
> +Example:
> +
> +pwm: pwm@80064000 {
> + compatible = "nxp,lpc3220-pwm";
> + reg = <0x80064000 2000>;
You probably want to specify the size as 0x2000 as well.
> +};
> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
> index 0b2800f..34086b1 100644
> --- a/drivers/pwm/Kconfig
> +++ b/drivers/pwm/Kconfig
> @@ -28,6 +28,17 @@ config PWM_IMX
> To compile this driver as a module, choose M here: the module
> will be called pwm-imx.
>
> +config PWM_LPC32XX
> + tristate "LPC32XX PWM support"
> + depends on ARCH_LPC32XX
> + help
> + Generic PWM framework driver for LPC32XX. The LPC32XX soc has two
> + pwm channels.
Can we keep the spelling consistent here? It should be "PWM" and "SoC".
It'd be nice if you could fix that up in the commit message as well.
> +
> + To compile this driver as a module, choose M here: the module
> + will be called pwm-lpc32xx.
> +
> +
> config PWM_MXS
> tristate "Freescale MXS PWM support"
> depends on ARCH_MXS && OF
> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
> index cec2500..5459702 100644
> --- a/drivers/pwm/Makefile
> +++ b/drivers/pwm/Makefile
> @@ -1,6 +1,7 @@
> obj-$(CONFIG_PWM) += core.o
> obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o
> obj-$(CONFIG_PWM_IMX) += pwm-imx.o
> +obj-$(CONFIG_PWM_LPC32XX) += pwm-lpc32xx.o
> obj-$(CONFIG_PWM_MXS) += pwm-mxs.o
> obj-$(CONFIG_PWM_PXA) += pwm-pxa.o
> obj-$(CONFIG_PWM_SAMSUNG) += pwm-samsung.o
> diff --git a/drivers/pwm/pwm-lpc32xx.c b/drivers/pwm/pwm-lpc32xx.c
> new file mode 100644
> index 0000000..c7fa126
> --- /dev/null
> +++ b/drivers/pwm/pwm-lpc32xx.c
> @@ -0,0 +1,151 @@
> +/*
> + * Copyright 2012 Alexandre Pereira da Silva <aletes.xgr@gmail.com>
> + *
> + * The code contained herein is licensed under the GNU General Public
> + * License. You may obtain a copy of the GNU General Public License
> + * Version 2 or later at the following locations:
> + *
> + * http://www.opensource.org/licenses/gpl-license.html
> + * http://www.gnu.org/copyleft/gpl.html
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/platform_device.h>
> +#include <linux/pwm.h>
> +#include <linux/slab.h>
> +
> +struct lpc32xx_pwm_chip {
> + struct pwm_chip chip;
> + struct device *dev;
Can you drop this field? You initialize it, but it is never used
subsequently in the driver.
> + struct clk *clk;
> + void __iomem *base;
> +};
> +
> +#define PWM_ENABLE (1<<31)
> +#define PWM_RELOADV(x) (((x) & 0xFF)<<8)
> +#define PWM_DUTY(x) ((x) & 0xFF)
There should be spaces around <<.
> +
> +#define to_lpc32xx_pwm_chip(_chip) \
> + container_of(_chip, struct lpc32xx_pwm_chip, chip)
> +
> +static int lpc32xx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
> + int duty_ns, int period_ns)
The alignment looks wrong here. It seems like you aligned properly
before adding the "static".
> +{
> + struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
> + unsigned long long c;
> + int period_cycles, duty_cycles;
> +
> + c = clk_get_rate(lpc32xx->clk)/256;
Spaces around /.
> + c = c * period_ns;
> + do_div(c, NSEC_PER_SEC);
> +
> + /* Handle high and low extremes */
> + if (c == 0)
> + c = 1;
> + if (c > 255)
> + c = 0; /* 0 set division by 256 */
> + period_cycles = c;
> +
> + c = 256*duty_ns;
Spaces around *.
> + do_div(c, period_ns);
> + duty_cycles = c;
> +
> + writel(PWM_ENABLE | PWM_RELOADV(period_cycles) | PWM_DUTY(duty_cycles),
> + lpc32xx->base);
> +
> + return 0;
> +}
> +
> +static int lpc32xx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
> +{
> + struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
> +
> + clk_enable(lpc32xx->clk);
> + return 0;
> +}
> +
> +static void lpc32xx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
> +{
> + struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
> +
> + writel(0, lpc32xx->base);
> + clk_disable(lpc32xx->clk);
> +}
> +
> +static const struct pwm_ops lpc32xx_pwm_ops = {
> + .config = lpc32xx_pwm_config,
> + .enable = lpc32xx_pwm_enable,
> + .disable = lpc32xx_pwm_disable,
> + .owner = THIS_MODULE,
> +};
> +
> +static int lpc32xx_pwm_probe(struct platform_device *pdev)
> +{
> + struct lpc32xx_pwm_chip *lpc32xx;
> + struct resource *res;
> + int ret;
> +
> + lpc32xx = devm_kzalloc(&pdev->dev, sizeof(*lpc32xx), GFP_KERNEL);
> + if (!lpc32xx)
> + return -ENOMEM;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
You should probably check for res != NULL.
> + lpc32xx->base = devm_request_and_ioremap(&pdev->dev, res);
> + if (!lpc32xx->base)
> + return -EADDRNOTAVAIL;
> +
> + lpc32xx->clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(lpc32xx->clk))
> + return PTR_ERR(lpc32xx->clk);
> +
> + lpc32xx->chip.dev = &pdev->dev;
> + lpc32xx->chip.ops = &lpc32xx_pwm_ops;
> + lpc32xx->chip.npwm = 1;
The Kconfig help text says that the lpc32xx PWM controller has two
channels. Why is npwm set to 1 here?
> +
> + ret = pwmchip_add(&lpc32xx->chip);
> + if (ret < 0) {
> + dev_err(&pdev->dev, "failed to add pwm chip %d\n", ret);
You should probably separate the error code, to make it obvious what it
is. Otherwise one might mistake this as an index. While at it, please
make PWM uppercase.
> + return ret;
> + }
> +
> + lpc32xx->dev = &pdev->dev;
As I mentioned above, this is unused so it can probably be dropped.
> + platform_set_drvdata(pdev, lpc32xx);
> +
> + return 0;
> +}
> +
> +static int __devexit lpc32xx_pwm_remove(struct platform_device *pdev)
> +{
> + struct lpc32xx_pwm_chip *lpc32xx = platform_get_drvdata(pdev);
> +
> + pwmchip_remove(&lpc32xx->chip);
You should propagate potential errors from pwmchip_remove(). There are
situations where it can actually fail.
Thierry
> +
> + return 0;
> +}
> +
> +static struct of_device_id lpc32xx_pwm_dt_ids[] = {
> + { .compatible = "nxp,lpc3220-pwm", },
> + { /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, lpc32xx_pwm_dt_ids);
> +
> +static struct platform_driver lpc32xx_pwm_driver = {
> + .driver = {
> + .name = "lpc32xx-pwm",
> + .of_match_table = of_match_ptr(lpc32xx_pwm_dt_ids),
> + },
> + .probe = lpc32xx_pwm_probe,
> + .remove = __devexit_p(lpc32xx_pwm_remove),
> +};
> +module_platform_driver(lpc32xx_pwm_driver);
> +
> +MODULE_ALIAS("platform:lpc32xx-pwm");
> +MODULE_AUTHOR("Alexandre Pereira da Silva <aletes.xgr@gmail.com>");
> +MODULE_DESCRIPTION("LPC32XX PWM Driver");
> +MODULE_LICENSE("GPL v2");
> --
> 1.7.10
>
>
>
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] pwm: add lpc32xx pwm support
2012-07-10 6:48 ` Thierry Reding
(?)
@ 2012-07-10 7:56 ` Roland Stigge
2012-07-10 8:00 ` Thierry Reding
-1 siblings, 1 reply; 6+ messages in thread
From: Roland Stigge @ 2012-07-10 7:56 UTC (permalink / raw)
To: Thierry Reding
Cc: Alexandre Pereira da Silva, Grant Likely, Rob Herring,
Rob Landley, linux-kernel, devicetree-discuss, linux-doc
Hi,
On 07/10/2012 08:48 AM, Thierry Reding wrote:
>> --- /dev/null +++
>> b/Documentation/devicetree/bindings/pwm/lpc32xx-pwm.txt @@ -0,0
>> +1,12 @@ +LPC32XX PWM controller + +Required properties: +-
>> compatible: should be "nxp,lpc3220-pwm"
>
> Does the compatible have to be lpc3220-pwm? Can't it be lpc32xx-pwm
> to match the driver and binding names?
When creating the other NXP LPC compatible strings, we agreed on
taking the first LPC32xx chip, i.e., lpc3220, as prefix. (There are 4
of them, -20, -30, -40, -50, most of them supporting things available
in lpc3220.)
So lpc3220-pwm looks good here.
Thanks also for the review. Will have a second look when Alexandre
posts an update.
Thank you two!
Roland
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] pwm: add lpc32xx pwm support
2012-07-10 7:56 ` Roland Stigge
@ 2012-07-10 8:00 ` Thierry Reding
0 siblings, 0 replies; 6+ messages in thread
From: Thierry Reding @ 2012-07-10 8:00 UTC (permalink / raw)
To: Roland Stigge
Cc: Alexandre Pereira da Silva, Grant Likely, Rob Herring,
Rob Landley, linux-kernel, devicetree-discuss, linux-doc
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On Tue, Jul 10, 2012 at 09:56:08AM +0200, Roland Stigge wrote:
> Hi,
>
> On 07/10/2012 08:48 AM, Thierry Reding wrote:
> >> --- /dev/null +++
> >> b/Documentation/devicetree/bindings/pwm/lpc32xx-pwm.txt @@ -0,0
> >> +1,12 @@ +LPC32XX PWM controller + +Required properties: +-
> >> compatible: should be "nxp,lpc3220-pwm"
> >
> > Does the compatible have to be lpc3220-pwm? Can't it be lpc32xx-pwm
> > to match the driver and binding names?
>
> When creating the other NXP LPC compatible strings, we agreed on
> taking the first LPC32xx chip, i.e., lpc3220, as prefix. (There are 4
> of them, -20, -30, -40, -50, most of them supporting things available
> in lpc3220.)
>
> So lpc3220-pwm looks good here.
I see, that makes sense.
Thierry
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] pwm: add lpc32xx pwm support
2012-07-10 6:48 ` Thierry Reding
(?)
(?)
@ 2012-07-10 11:35 ` Alexandre Pereira da Silva
-1 siblings, 0 replies; 6+ messages in thread
From: Alexandre Pereira da Silva @ 2012-07-10 11:35 UTC (permalink / raw)
To: Thierry Reding
Cc: Roland Stigge, Grant Likely, Rob Herring, Rob Landley,
linux-kernel, devicetree-discuss, linux-doc
On Tue, Jul 10, 2012 at 3:48 AM, Thierry Reding
<thierry.reding@avionic-design.de> wrote:
> On Mon, Jul 09, 2012 at 04:27:54PM -0300, Alexandre Pereira da Silva wrote:
>> Add lpc32xx soc pwm driver.
>>
>> Signed-off-by: Alexandre Pereira da Silva <aletes.xgr@gmail.com>
>> ---
>> .../devicetree/bindings/pwm/lpc32xx-pwm.txt | 12 ++
>> drivers/pwm/Kconfig | 11 ++
>> drivers/pwm/Makefile | 1 +
>> drivers/pwm/pwm-lpc32xx.c | 151 ++++++++++++++++++++
>> 4 files changed, 175 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/pwm/lpc32xx-pwm.txt
>> create mode 100644 drivers/pwm/pwm-lpc32xx.c
>
> Hi Alexandre,
>
> overall this looks good, just some comments inline. I'd very much
> appreciate an Acked-by from Roland on this.
>
>> diff --git a/Documentation/devicetree/bindings/pwm/lpc32xx-pwm.txt b/Documentation/devicetree/bindings/pwm/lpc32xx-pwm.txt
>> new file mode 100644
>> index 0000000..fb7b3d5
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/pwm/lpc32xx-pwm.txt
>> @@ -0,0 +1,12 @@
>> +LPC32XX PWM controller
>> +
>> +Required properties:
>> +- compatible: should be "nxp,lpc3220-pwm"
>
> Does the compatible have to be lpc3220-pwm? Can't it be lpc32xx-pwm to
> match the driver and binding names?
>
>> +- reg: physical base address and length of the controller's registers
>> +
>> +Example:
>> +
>> +pwm: pwm@80064000 {
>> + compatible = "nxp,lpc3220-pwm";
>> + reg = <0x80064000 2000>;
>
> You probably want to specify the size as 0x2000 as well.
I will copy here the dts for the two pwm controllers this chip has.
This should have been 4 instead.
>> +};
>> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
>> index 0b2800f..34086b1 100644
>> --- a/drivers/pwm/Kconfig
>> +++ b/drivers/pwm/Kconfig
>> @@ -28,6 +28,17 @@ config PWM_IMX
>> To compile this driver as a module, choose M here: the module
>> will be called pwm-imx.
>>
>> +config PWM_LPC32XX
>> + tristate "LPC32XX PWM support"
>> + depends on ARCH_LPC32XX
>> + help
>> + Generic PWM framework driver for LPC32XX. The LPC32XX soc has two
>> + pwm channels.
>
> Can we keep the spelling consistent here? It should be "PWM" and "SoC".
> It'd be nice if you could fix that up in the commit message as well.
>
>> +
>> + To compile this driver as a module, choose M here: the module
>> + will be called pwm-lpc32xx.
>> +
>> +
>> config PWM_MXS
>> tristate "Freescale MXS PWM support"
>> depends on ARCH_MXS && OF
>> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
>> index cec2500..5459702 100644
>> --- a/drivers/pwm/Makefile
>> +++ b/drivers/pwm/Makefile
>> @@ -1,6 +1,7 @@
>> obj-$(CONFIG_PWM) += core.o
>> obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o
>> obj-$(CONFIG_PWM_IMX) += pwm-imx.o
>> +obj-$(CONFIG_PWM_LPC32XX) += pwm-lpc32xx.o
>> obj-$(CONFIG_PWM_MXS) += pwm-mxs.o
>> obj-$(CONFIG_PWM_PXA) += pwm-pxa.o
>> obj-$(CONFIG_PWM_SAMSUNG) += pwm-samsung.o
>> diff --git a/drivers/pwm/pwm-lpc32xx.c b/drivers/pwm/pwm-lpc32xx.c
>> new file mode 100644
>> index 0000000..c7fa126
>> --- /dev/null
>> +++ b/drivers/pwm/pwm-lpc32xx.c
>> @@ -0,0 +1,151 @@
>> +/*
>> + * Copyright 2012 Alexandre Pereira da Silva <aletes.xgr@gmail.com>
>> + *
>> + * The code contained herein is licensed under the GNU General Public
>> + * License. You may obtain a copy of the GNU General Public License
>> + * Version 2 or later at the following locations:
>> + *
>> + * http://www.opensource.org/licenses/gpl-license.html
>> + * http://www.gnu.org/copyleft/gpl.html
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/err.h>
>> +#include <linux/io.h>
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/of_address.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/pwm.h>
>> +#include <linux/slab.h>
>> +
>> +struct lpc32xx_pwm_chip {
>> + struct pwm_chip chip;
>> + struct device *dev;
>
> Can you drop this field? You initialize it, but it is never used
> subsequently in the driver.
>
>> + struct clk *clk;
>> + void __iomem *base;
>> +};
>> +
>> +#define PWM_ENABLE (1<<31)
>> +#define PWM_RELOADV(x) (((x) & 0xFF)<<8)
>> +#define PWM_DUTY(x) ((x) & 0xFF)
>
> There should be spaces around <<.
>
>> +
>> +#define to_lpc32xx_pwm_chip(_chip) \
>> + container_of(_chip, struct lpc32xx_pwm_chip, chip)
>> +
>> +static int lpc32xx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
>> + int duty_ns, int period_ns)
>
> The alignment looks wrong here. It seems like you aligned properly
> before adding the "static".
>
>> +{
>> + struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
>> + unsigned long long c;
>> + int period_cycles, duty_cycles;
>> +
>> + c = clk_get_rate(lpc32xx->clk)/256;
>
> Spaces around /.
>
>> + c = c * period_ns;
>> + do_div(c, NSEC_PER_SEC);
>> +
>> + /* Handle high and low extremes */
>> + if (c == 0)
>> + c = 1;
>> + if (c > 255)
>> + c = 0; /* 0 set division by 256 */
>> + period_cycles = c;
>> +
>> + c = 256*duty_ns;
>
> Spaces around *.
>
>> + do_div(c, period_ns);
>> + duty_cycles = c;
>> +
>> + writel(PWM_ENABLE | PWM_RELOADV(period_cycles) | PWM_DUTY(duty_cycles),
>> + lpc32xx->base);
>> +
>> + return 0;
>> +}
>> +
>> +static int lpc32xx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
>> +{
>> + struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
>> +
>> + clk_enable(lpc32xx->clk);
>> + return 0;
>> +}
>> +
>> +static void lpc32xx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
>> +{
>> + struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
>> +
>> + writel(0, lpc32xx->base);
>> + clk_disable(lpc32xx->clk);
>> +}
>> +
>> +static const struct pwm_ops lpc32xx_pwm_ops = {
>> + .config = lpc32xx_pwm_config,
>> + .enable = lpc32xx_pwm_enable,
>> + .disable = lpc32xx_pwm_disable,
>> + .owner = THIS_MODULE,
>> +};
>> +
>> +static int lpc32xx_pwm_probe(struct platform_device *pdev)
>> +{
>> + struct lpc32xx_pwm_chip *lpc32xx;
>> + struct resource *res;
>> + int ret;
>> +
>> + lpc32xx = devm_kzalloc(&pdev->dev, sizeof(*lpc32xx), GFP_KERNEL);
>> + if (!lpc32xx)
>> + return -ENOMEM;
>> +
>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>
> You should probably check for res != NULL.
>
>> + lpc32xx->base = devm_request_and_ioremap(&pdev->dev, res);
>> + if (!lpc32xx->base)
>> + return -EADDRNOTAVAIL;
>> +
>> + lpc32xx->clk = devm_clk_get(&pdev->dev, NULL);
>> + if (IS_ERR(lpc32xx->clk))
>> + return PTR_ERR(lpc32xx->clk);
>> +
>> + lpc32xx->chip.dev = &pdev->dev;
>> + lpc32xx->chip.ops = &lpc32xx_pwm_ops;
>> + lpc32xx->chip.npwm = 1;
>
> The Kconfig help text says that the lpc32xx PWM controller has two
> channels. Why is npwm set to 1 here?
I will improve the description. We have two independent controllers instead.
Thanks for reviewing. I will fix all the other issues that you found as well.
^ permalink raw reply [flat|nested] 6+ messages in thread