Re: [PATCH] pwm_lpss: Add support for PCI devices

[Darren Hart]

On Sat, Apr 12, 2014 at 09:58:51PM +0800, Chew Chiau Ee wrote:
> From: Alan Cox <alan@xxxxxxxxxxxxxxx>
> 
> Not all systems enumerate the PWM devices via ACPI. They can also be exposed
> via the PCI interface.
> 
> Signed-off-by: Alan Cox <alan@xxxxxxxxxxxxxxx>
> Signed-off-by: Chew, Chiau Ee <chiau.ee.chew@xxxxxxxxx>
> ---
>  drivers/pwm/pwm-lpss.c |  160 ++++++++++++++++++++++++++++++++++++++---------
>  1 files changed, 129 insertions(+), 31 deletions(-)
> 
> diff --git a/drivers/pwm/pwm-lpss.c b/drivers/pwm/pwm-lpss.c
> index 449e372..6f79bf8 100644
> --- a/drivers/pwm/pwm-lpss.c
> +++ b/drivers/pwm/pwm-lpss.c
> @@ -6,6 +6,7 @@
>   * Author: Chew Kean Ho <kean.ho.chew@xxxxxxxxx>
>   * Author: Chang Rebecca Swee Fun <rebecca.swee.fun.chang@xxxxxxxxx>
>   * Author: Chew Chiau Ee <chiau.ee.chew@xxxxxxxxx>
> + * Author: Alan Cox <alan@xxxxxxxxxxxxxxx>
>   *
>   * This program is free software; you can redistribute it and/or modify
>   * it under the terms of the GNU General Public License version 2 as
> @@ -19,6 +20,9 @@
>  #include <linux/module.h>
>  #include <linux/pwm.h>
>  #include <linux/platform_device.h>
> +#include <linux/pci.h>
> +
> +static int pci_drv, plat_drv;	/* So we know which drivers registered */
>  
>  #define PWM				0x00000000
>  #define PWM_ENABLE			BIT(31)
> @@ -34,6 +38,15 @@ struct pwm_lpss_chip {
>  	struct pwm_chip chip;
>  	void __iomem *regs;
>  	struct clk *clk;
> +	unsigned long clk_rate;
> +};
> +
> +struct pwm_lpss_boardinfo {
> +	unsigned long clk_rate;
> +};
> +
> +static const struct pwm_lpss_boardinfo byt_info = {
> +	25000000
>  };
>  
>  static inline struct pwm_lpss_chip *to_lpwm(struct pwm_chip *chip)
> @@ -55,7 +68,7 @@ static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
>  	/* The equation is: base_unit = ((freq / c) * 65536) + correction */
>  	base_unit = freq * 65536;
>  
> -	c = clk_get_rate(lpwm->clk);
> +	c = lpwm->clk_rate;
>  	if (!c)
>  		return -EINVAL;
>  
> @@ -113,52 +126,47 @@ static const struct pwm_ops pwm_lpss_ops = {
>  	.owner = THIS_MODULE,
>  };
>  
> -static const struct acpi_device_id pwm_lpss_acpi_match[] = {
> -	{ "80860F09", 0 },
> -	{ },
> -};
> -MODULE_DEVICE_TABLE(acpi, pwm_lpss_acpi_match);
> -
> -static int pwm_lpss_probe(struct platform_device *pdev)
> +static struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev,
> +			struct resource *r, struct pwm_lpss_boardinfo *info)

Has this landed anywhere? I didn't see it in mainline or next, am I looking in
the wrong place? If it's just still pending, I ran into one issue integrating it
with 3.14.2:

  CC [M]  drivers/pwm/pwm-lpss.o
  drivers/pwm/pwm-lpss.c: In function âpwm_lpss_probe_pciâ:
  drivers/pwm/pwm-lpss.c:192:2: warning: passing argument 3 of âpwm_lpss_probeâ
  discards âconstâ qualifier from pointer target type [enabled by default]
  drivers/pwm/pwm-lpss.c:130:30: note: expected âstruct pwm_lpss_boardinfo *â
  but argument is of type âconst struct pwm_lpss_boardinfo *â

Can we make the third argument to pwm_lpss_probe a const? The following is
working for me:

 static struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev,
                                             struct resource *r,
                                             const struct pwm_lpss_boardinfo *info)

Thanks,

--
Darren Hart			Open Source Technology Center
darren.hart@xxxxxxxxx		Intel Corporation
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