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From: Marc Kleine-Budde <mkl@pengutronix.de>
To: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Cc: linux-can@vger.kernel.org, "Stefan Mätje" <Stefan.Maetje@esd.eu>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 4/7] can: dev: add can_tdc_get_relative_tdco() helper function
Date: Mon, 16 Aug 2021 13:27:03 +0200	[thread overview]
Message-ID: <20210816112703.y6olntctn3oaavng@pengutronix.de> (raw)
In-Reply-To: <20210815033248.98111-5-mailhol.vincent@wanadoo.fr>

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On 15.08.2021 12:32:45, Vincent Mailhol wrote:
> struct can_tdc::tdco represents the absolute offset from TDCV. Some
> controllers use instead an offset relative to the Sample Point (SP)
> such that:
> | SSP = TDCV + absolute TDCO
> |     = TDCV + SP + relative TDCO
> 
> Consequently:
> | relative TDCO = absolute TDCO - SP
> 
> The function can_tdc_get_relative_tdco() allow to retrieve this
> relative TDCO value.
> 
> CC: Stefan Mätje <Stefan.Maetje@esd.eu>
> Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
> ---
>  include/linux/can/dev.h | 29 +++++++++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
> 
> diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h
> index 0be982fd22fb..fa75e29182a3 100644
> --- a/include/linux/can/dev.h
> +++ b/include/linux/can/dev.h
> @@ -93,6 +93,35 @@ static inline bool can_tdc_is_enabled(const struct can_priv *priv)
>  	return !!(priv->ctrlmode & CAN_CTRLMODE_TDC_MASK);
>  }
>  
> +/*
> + * can_get_relative_tdco() - TDCO relative to the sample point
> + *
> + * struct can_tdc::tdco represents the absolute offset from TDCV. Some
> + * controllers use instead an offset relative to the Sample Point (SP)
> + * such that:
> + *
> + * SSP = TDCV + absolute TDCO
> + *     = TDCV + SP + relative TDCO
> + *
> + * -+----------- one bit ----------+-- TX pin
> + *  |<--- Sample Point --->|
> + *
> + *                         --+----------- one bit ----------+-- RX pin
> + *  |<-------- TDCV -------->|
> + *                           |<------------------------>| absolute TDCO
> + *                           |<--- Sample Point --->|
> + *                           |                      |<->| relative TDCO
> + *  |<------------- Secondary Sample Point ------------>|
> + */
> +static inline s32 can_get_relative_tdco(const struct can_priv *priv)
> +{
> +	const struct can_bittiming *dbt = &priv->data_bittiming;
> +	s32 sample_point_in_tc =  (CAN_SYNC_SEG + dbt->prop_seg +
                                ^^

Only one space. I'll fix the while applying.

> +				   dbt->phase_seg1) * dbt->brp;
> +
> +	return (s32)priv->tdc.tdco - sample_point_in_tc;
> +}
> +
>  /* helper to define static CAN controller features at device creation time */
>  static inline void can_set_static_ctrlmode(struct net_device *dev,
>  					   u32 static_mode)

Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde           |
Embedded Linux                   | https://www.pengutronix.de  |
Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |

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  reply	other threads:[~2021-08-16 11:27 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-15  3:32 [PATCH v5 0/7] add the netlink interface for CAN-FD Transmitter Delay Compensation (TDC) Vincent Mailhol
2021-08-15  3:32 ` [PATCH v5 1/7] can: netlink: allow user to turn off unsupported features Vincent Mailhol
2021-08-19  7:45   ` Marc Kleine-Budde
2021-08-19  9:24     ` Vincent MAILHOL
2021-08-19 10:07       ` Marc Kleine-Budde
2021-08-15  3:32 ` [PATCH v5 2/7] can: bittiming: allow TDC{V,O} to be zero and add can_tdc_const::tdc{v,o,f}_min Vincent Mailhol
2021-08-16  8:42   ` Marc Kleine-Budde
2021-08-16 10:24     ` Vincent MAILHOL
2021-08-16 12:25       ` Marc Kleine-Budde
2021-08-16 12:33         ` Marc Kleine-Budde
2021-08-16 13:43           ` Marc Kleine-Budde
2021-08-16 15:49             ` Vincent MAILHOL
2021-08-16 16:04               ` Vincent MAILHOL
2021-08-17  1:12                 ` Vincent MAILHOL
2021-08-17 20:01               ` Marc Kleine-Budde
2021-08-18  9:22                 ` Vincent MAILHOL
2021-08-18 12:29                   ` Marc Kleine-Budde
2021-08-18 14:17                     ` Vincent MAILHOL
2021-08-20  6:12                       ` Vincent MAILHOL
2021-08-16 14:10           ` Vincent MAILHOL
2021-08-16 14:30             ` Marc Kleine-Budde
2021-08-17  9:43               ` Marc Kleine-Budde
2021-08-16 13:49         ` Stefan Mätje
2021-08-16 15:56           ` Vincent MAILHOL
2021-08-15  3:32 ` [PATCH v5 3/7] can: bittiming: change unit of TDC parameters to clock periods Vincent Mailhol
2021-08-15  3:32 ` [PATCH v5 4/7] can: dev: add can_tdc_get_relative_tdco() helper function Vincent Mailhol
2021-08-16 11:27   ` Marc Kleine-Budde [this message]
2021-08-15  3:32 ` [PATCH v5 5/7] can: netlink: add interface for CAN-FD Transmitter Delay Compensation (TDC) Vincent Mailhol
2021-08-17 19:55   ` Marc Kleine-Budde
2021-08-18  8:08     ` Vincent MAILHOL
2021-08-18  8:19       ` Marc Kleine-Budde
2021-08-18  8:37         ` Vincent MAILHOL
2021-08-18  8:43           ` Marc Kleine-Budde
2021-08-15  3:32 ` [PATCH v5 6/7] can: netlink: add can_priv::do_get_auto_tdcv() to retrieve tdcv from device Vincent Mailhol
2021-08-15  3:32 ` [PATCH v5 7/7] can: etas_es58x: clean-up documentation of struct es58x_fd_tx_conf_msg Vincent Mailhol
2021-08-19 10:08   ` Marc Kleine-Budde

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