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Date: Tue, 3 Dec 2019 19:21:36 +0100
From: Marc Kleine-Budde <mkl@...gutronix.de>
To: Joakim Zhang <qiangqing.zhang@....com>,
"sean@...nix.com" <sean@...nix.com>,
"linux-can@...r.kernel.org" <linux-can@...r.kernel.org>
Cc: dl-linux-imx <linux-imx@....com>,
"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: [PATCH V2 3/4] can: flexcan: change the way of stop mode
acknowledgment
On 11/27/19 6:56 AM, Joakim Zhang wrote:
> Stop mode is entered when Stop mode is requested at chip level and
> MCR[LPM_ACK] is asserted by the FlexCAN.
>
> Double check with IP owner, should poll MCR[LPM_ACK] for stop mode
> acknowledgment, not the acknowledgment from chip level which is used
> for glitch filter.
>
> Fixes: 5f186c257fa4(can: flexcan: fix stop mode acknowledgment)
> Signed-off-by: Joakim Zhang <qiangqing.zhang@....com>
> ------
> ChangeLog:
> V1->V2: no change.
> ---
> drivers/net/can/flexcan.c | 64 ++++++++++++++++++++-------------------
> 1 file changed, 33 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
> index 5d5ed28d3005..d178146b3da5 100644
> --- a/drivers/net/can/flexcan.c
> +++ b/drivers/net/can/flexcan.c
> @@ -388,6 +388,34 @@ static struct flexcan_mb __iomem *flexcan_get_mb(const struct flexcan_priv *priv
> (&priv->regs->mb[bank][priv->mb_size * mb_index]);
> }
>
> +static int flexcan_enter_low_power_ack(struct flexcan_priv *priv)
nitpick: please call this flexcan_low_power_enter_ack()
> +{
> + struct flexcan_regs __iomem *regs = priv->regs;
> + unsigned int timeout = FLEXCAN_TIMEOUT_US / 10;
> +
> + while (timeout-- && !(priv->read(®s->mcr) & FLEXCAN_MCR_LPM_ACK))
> + udelay(10);
> +
> + if (!(priv->read(®s->mcr) & FLEXCAN_MCR_LPM_ACK))
> + return -ETIMEDOUT;
> +
> + return 0;
> +}
> +
> +static int flexcan_exit_low_power_ack(struct flexcan_priv *priv)
...and this one flexcan_low_power_exit_ack()
> +{
> + struct flexcan_regs __iomem *regs = priv->regs;
> + unsigned int timeout = FLEXCAN_TIMEOUT_US / 10;
> +
> + while (timeout-- && (priv->read(®s->mcr) & FLEXCAN_MCR_LPM_ACK))
> + udelay(10);
> +
> + if (priv->read(®s->mcr) & FLEXCAN_MCR_LPM_ACK)
> + return -ETIMEDOUT;
> +
> + return 0;
> +}
Can you move split the creation of
flexcan_low_power_enter_ack()/flexcan_low_power_exit_ack() and use in
flexcan_chip_enable/disable() into one patch and the conversion of
flexcan_enter_stop_mode()/flexcan_exit_stop_mode() into another.
Marc
> +
> static void flexcan_enable_wakeup_irq(struct flexcan_priv *priv, bool enable)
> {
> struct flexcan_regs __iomem *regs = priv->regs;
> @@ -406,7 +434,6 @@ static void flexcan_enable_wakeup_irq(struct flexcan_priv *priv, bool enable)
> static inline int flexcan_enter_stop_mode(struct flexcan_priv *priv)
> {
> struct flexcan_regs __iomem *regs = priv->regs;
> - unsigned int ackval;
> u32 reg_mcr;
>
> reg_mcr = priv->read(®s->mcr);
> @@ -418,35 +445,24 @@ static inline int flexcan_enter_stop_mode(struct flexcan_priv *priv)
> 1 << priv->stm.req_bit, 1 << priv->stm.req_bit);
>
> /* get stop acknowledgment */
> - if (regmap_read_poll_timeout(priv->stm.gpr, priv->stm.ack_gpr,
> - ackval, ackval & (1 << priv->stm.ack_bit),
> - 0, FLEXCAN_TIMEOUT_US))
> - return -ETIMEDOUT;
> -
> - return 0;
> + return flexcan_enter_low_power_ack(priv);
> }
>
> static inline int flexcan_exit_stop_mode(struct flexcan_priv *priv)
> {
> struct flexcan_regs __iomem *regs = priv->regs;
> - unsigned int ackval;
> u32 reg_mcr;
>
> /* remove stop request */
> regmap_update_bits(priv->stm.gpr, priv->stm.req_gpr,
> 1 << priv->stm.req_bit, 0);
>
> - /* get stop acknowledgment */
> - if (regmap_read_poll_timeout(priv->stm.gpr, priv->stm.ack_gpr,
> - ackval, !(ackval & (1 << priv->stm.ack_bit)),
> - 0, FLEXCAN_TIMEOUT_US))
> - return -ETIMEDOUT;
> -
> reg_mcr = priv->read(®s->mcr);
> reg_mcr &= ~FLEXCAN_MCR_SLF_WAK;
> priv->write(reg_mcr, ®s->mcr);
>
> - return 0;
> + /* get stop acknowledgment */
> + return flexcan_exit_low_power_ack(priv);
> }
>
> static void flexcan_try_exit_stop_mode(struct flexcan_priv *priv)
> @@ -512,39 +528,25 @@ static inline int flexcan_transceiver_disable(const struct flexcan_priv *priv)
> static int flexcan_chip_enable(struct flexcan_priv *priv)
> {
> struct flexcan_regs __iomem *regs = priv->regs;
> - unsigned int timeout = FLEXCAN_TIMEOUT_US / 10;
> u32 reg;
>
> reg = priv->read(®s->mcr);
> reg &= ~FLEXCAN_MCR_MDIS;
> priv->write(reg, ®s->mcr);
>
> - while (timeout-- && (priv->read(®s->mcr) & FLEXCAN_MCR_LPM_ACK))
> - udelay(10);
> -
> - if (priv->read(®s->mcr) & FLEXCAN_MCR_LPM_ACK)
> - return -ETIMEDOUT;
> -
> - return 0;
> + return flexcan_exit_low_power_ack(priv);
> }
>
> static int flexcan_chip_disable(struct flexcan_priv *priv)
> {
> struct flexcan_regs __iomem *regs = priv->regs;
> - unsigned int timeout = FLEXCAN_TIMEOUT_US / 10;
> u32 reg;
>
> reg = priv->read(®s->mcr);
> reg |= FLEXCAN_MCR_MDIS;
> priv->write(reg, ®s->mcr);
>
> - while (timeout-- && !(priv->read(®s->mcr) & FLEXCAN_MCR_LPM_ACK))
> - udelay(10);
> -
> - if (!(priv->read(®s->mcr) & FLEXCAN_MCR_LPM_ACK))
> - return -ETIMEDOUT;
> -
> - return 0;
> + return flexcan_enter_low_power_ack(priv);
> }
>
> static int flexcan_chip_freeze(struct flexcan_priv *priv)
>
--
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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