linux-kernel - Re: [PATCH 1/3] usb: chipidea: Add identification registers access APIs

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Message-ID: <4f5efe169ed3ab16ffcbee52dd6b7661@agner.ch>
Date:	Wed, 24 Dec 2014 17:00:05 +0100
From:	Stefan Agner <stefan@...er.ch>
To:	Sanchayan Maity <maitysanchayan@...il.com>
Cc:	Peter.Chen@...escale.com, gregkh@...uxfoundation.org,
	linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] usb: chipidea: Add identification registers access
 APIs

On 2014-12-19 10:55, Sanchayan Maity wrote:
> Using hw_write_id_reg and hw_read_id_reg to write and read
> identification registers contents. This can be used to get
> controller information, change some system configurations
> and so on.

Checkpatch is complaining about DOS line endings and some trailing
whitespace. This applies to all three patches.

> 
> Signed-off-by: Sanchayan Maity <maitysanchayan@...il.com>
> ---
>  drivers/usb/chipidea/ci.h |   53 +++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 53 insertions(+)
> 
> diff --git a/drivers/usb/chipidea/ci.h b/drivers/usb/chipidea/ci.h
> index ea40626..94db636 100644
> --- a/drivers/usb/chipidea/ci.h
> +++ b/drivers/usb/chipidea/ci.h
> @@ -29,6 +29,15 @@
>  /******************************************************************************
>   * REGISTERS
>   *****************************************************************************/
> +/* Identification Registers */
> +#define ID_ID				0x0
> +#define ID_HWGENERAL			0x4
> +#define ID_HWHOST			0x8
> +#define ID_HWDEVICE			0xc
> +#define ID_HWTXBUF			0x10
> +#define ID_HWRXBUF			0x14
> +#define ID_SBUSCFG			0x90
> +
>  /* register indices */
>  enum ci_hw_regs {
>  	CAP_CAPLENGTH,
> @@ -97,6 +106,18 @@ enum ci_role {
>  	CI_ROLE_END,
>  };
>  
> +enum CI_REVISION {

Usually the enum names are small caps, only the labels are capitalized.
I would suggest use ci_revision here (similar to the enum above).

> +	CI_REVISION_1X = 10,	/* Revision 1.x */
> +	CI_REVISION_20 = 20, /* Revision 2.0 */
> +	CI_REVISION_21, /* Revision 2.1 */
> +	CI_REVISION_22, /* Revision 2.2 */
> +	CI_REVISION_23, /* Revision 2.3 */
> +	CI_REVISION_24, /* Revision 2.4 */
> +	CI_REVISION_25, /* Revision 2.5 */
> +	CI_REVISION_25_PLUS, /* Revision above than 2.5 */
> +	CI_REVISION_UNKNOWN = 99, /* Unknown Revision */
> +};
> +
>  /**
>   * struct ci_role_driver - host/gadget role driver
>   * @start: start this role
> @@ -168,6 +189,7 @@ struct hw_bank {
>   * @b_sess_valid_event: indicates there is a vbus event, and handled
>   * at ci_otg_work
>   * @imx28_write_fix: Freescale imx28 needs swp instruction for writing
> + * @rev: The revision number for controller
>   */
>  struct ci_hdrc {
>  	struct device			*dev;
> @@ -207,6 +229,7 @@ struct ci_hdrc {
>  	bool				id_event;
>  	bool				b_sess_valid_event;
>  	bool				imx28_write_fix;
> +	enum CI_REVISION		rev;
>  };
>  
>  static inline struct ci_role_driver *ci_role(struct ci_hdrc *ci)
> @@ -244,6 +267,36 @@ static inline void ci_role_stop(struct ci_hdrc *ci)
>  }
>  
>  /**
> + * hw_read_id_reg: reads from a identification register
> + * @ci: the controller
> + * @offset: offset from the beginning of identification registers region
> + * @mask: bitfield mask
> + *
> + * This function returns register contents
> + */
> +static inline u32 hw_read_id_reg(struct ci_hdrc *ci, u32 offset, u32 mask)
> +{
> +	return ioread32(ci->hw_bank.abs + offset) & mask;
> +}
> +
> +/**
> + * hw_write_id_reg: writes to a identification register
> + * @ci: the controller
> + * @offset: offset from the beginning of identification registers region
> + * @mask: bitfield mask
> + * @data: new value
> + */
> +static inline void hw_write_id_reg(struct ci_hdrc *ci, u32 offset,
> +			    u32 mask, u32 data)
> +{
> +	if (~mask)
> +		data = (ioread32(ci->hw_bank.abs + offset) & ~mask)
> +			| (data & mask);
> +
> +	iowrite32(data, ci->hw_bank.abs + offset);
> +}

This function isn't used anywhere, does it make sense to write an ID
register? The ones I see in Vybrid's RM are read-only anyway..

--
Stefan

> +
> +/**
>   * hw_read: reads from a hw register
>   * @ci: the controller
>   * @reg:  register index

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