Re: [PATCH v2 1/6] can: esd_usb: Make use of existing kernel macros

[Vincent MAILHOL]

Thanks for the patch.

On Sat. 20 May 2023 at 04:57, Frank Jungclaus <frank.jungclaus@xxxxxx> wrote:
> Make use of existing kernel macros:
> - Use the unit suffixes from linux/units.h for the controller clock
> frequencies
> - Use the BIT() and the GENMASK() macro to set specific bits in some
>   constants
> - Use CAN_MAX_DLEN (instead of directly using the value 8) for the
> maximum CAN payload length
>
> Additionally:
> - Spend some commenting for the previously changed constants
> - Add the current year to the copyright notice
> - While adding the header linux/units.h to the list of include files
> also sort that list alphabetically
>
> Suggested-by: Vincent MAILHOL <mailhol.vincent@xxxxxxxxxx>
> Link: https://lore.kernel.org/all/CAMZ6RqLaDNy-fZ2G0+QMhUEckkXLL+ZyELVSDFmqpd++aBzZQg@xxxxxxxxxxxxxx/
> Link: https://lore.kernel.org/all/CAMZ6RqKdg5YBufa0C+ttzJvoG=9yuti-8AmthCi4jBbd08JEtw@xxxxxxxxxxxxxx/
> Suggested-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
> Link: https://lore.kernel.org/all/20230518-grower-film-ea8b5f853f3e-mkl@xxxxxxxxxxxxxx/
> Signed-off-by: Frank Jungclaus <frank.jungclaus@xxxxxx>
> ---
>  drivers/net/can/usb/esd_usb.c | 40 ++++++++++++++++++-----------------
>  1 file changed, 21 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/net/can/usb/esd_usb.c b/drivers/net/can/usb/esd_usb.c
> index d33bac3a6c10..32354cfdf151 100644
> --- a/drivers/net/can/usb/esd_usb.c
> +++ b/drivers/net/can/usb/esd_usb.c
> @@ -3,19 +3,20 @@
>   * CAN driver for esd electronics gmbh CAN-USB/2 and CAN-USB/Micro
>   *
>   * Copyright (C) 2010-2012 esd electronic system design gmbh, Matthias Fuchs <socketcan@xxxxxx>
> - * Copyright (C) 2022 esd electronics gmbh, Frank Jungclaus <frank.jungclaus@xxxxxx>
> + * Copyright (C) 2022-2023 esd electronics gmbh, Frank Jungclaus <frank.jungclaus@xxxxxx>
>   */
> +#include <linux/can.h>
> +#include <linux/can/dev.h>
> +#include <linux/can/error.h>
> +
>  #include <linux/ethtool.h>
> -#include <linux/signal.h>
> -#include <linux/slab.h>
>  #include <linux/module.h>
>  #include <linux/netdevice.h>
> +#include <linux/signal.h>
> +#include <linux/slab.h>
> +#include <linux/units.h>
>  #include <linux/usb.h>
>
> -#include <linux/can.h>
> -#include <linux/can/dev.h>
> -#include <linux/can/error.h>
> -
>  MODULE_AUTHOR("Matthias Fuchs <socketcan@xxxxxx>");
>  MODULE_AUTHOR("Frank Jungclaus <frank.jungclaus@xxxxxx>");
>  MODULE_DESCRIPTION("CAN driver for esd electronics gmbh CAN-USB/2 and CAN-USB/Micro interfaces");
> @@ -27,8 +28,8 @@ MODULE_LICENSE("GPL v2");
>  #define USB_CANUSBM_PRODUCT_ID 0x0011
>
>  /* CAN controller clock frequencies */
> -#define ESD_USB2_CAN_CLOCK     60000000
> -#define ESD_USBM_CAN_CLOCK     36000000
> +#define ESD_USB2_CAN_CLOCK     (60 * MEGA) /* Hz */
> +#define ESD_USBM_CAN_CLOCK     (36 * MEGA) /* Hz */
>
>  /* Maximum number of CAN nets */
>  #define ESD_USB_MAX_NETS       2
> @@ -42,20 +43,21 @@ MODULE_LICENSE("GPL v2");
>  #define CMD_IDADD              6 /* also used for IDADD_REPLY */
>
>  /* esd CAN message flags - dlc field */
> -#define ESD_RTR                        0x10
> +#define ESD_RTR        BIT(4)
> +
>
>  /* esd CAN message flags - id field */
> -#define ESD_EXTID              0x20000000
> -#define ESD_EVENT              0x40000000
> -#define ESD_IDMASK             0x1fffffff
> +#define ESD_EXTID      BIT(29)
> +#define ESD_EVENT      BIT(30)
> +#define ESD_IDMASK     GENMASK(28, 0)
>
>  /* esd CAN event ids */
>  #define ESD_EV_CAN_ERROR_EXT   2 /* CAN controller specific diagnostic data */
>
>  /* baudrate message flags */
> -#define ESD_USB_UBR            0x80000000
> -#define ESD_USB_LOM            0x40000000
> -#define ESD_USB_NO_BAUDRATE    0x7fffffff
> +#define ESD_USB_LOM    BIT(30) /* 0x40000000, Listen Only Mode */
> +#define ESD_USB_UBR    BIT(31) /* 0x80000000, User Bit Rate (controller BTR) in bits 0..27 */
                                     ^^^^^^^^^^

As pointented by Marc, no need for redundant comment with the hexadecimal value.

> +#define ESD_USB_NO_BAUDRATE    GENMASK(30, 0) /* bit rate unconfigured */
>
>  /* bit timing CAN-USB/2 */
>  #define ESD_USB2_TSEG1_MIN     1
> @@ -70,7 +72,7 @@ MODULE_LICENSE("GPL v2");
>  #define ESD_USB2_BRP_MIN       1
>  #define ESD_USB2_BRP_MAX       1024
>  #define ESD_USB2_BRP_INC       1
> -#define ESD_USB2_3_SAMPLES     0x00800000
> +#define ESD_USB2_3_SAMPLES     BIT(23)
>
>  /* esd IDADD message */
>  #define ESD_ID_ENABLE          0x80
> @@ -128,7 +130,7 @@ struct rx_msg {
>         __le32 ts;
>         __le32 id; /* upper 3 bits contain flags */
>         union {
> -               u8 data[8];
> +               u8 data[CAN_MAX_DLEN];
>                 struct {
>                         u8 status; /* CAN Controller Status */
>                         u8 ecc;    /* Error Capture Register */
> @@ -145,7 +147,7 @@ struct tx_msg {
>         u8 dlc;
>         u32 hnd;        /* opaque handle, not used by device */
>         __le32 id; /* upper 3 bits contain flags */
> -       u8 data[8];
> +       u8 data[CAN_MAX_DLEN];
>  };
>
>  struct tx_done_msg {
> --
> 2.25.1
>