[PATCH 5.4 376/434] can: flexcan: poll MCR_LPM_ACK instead of GPR ACK for stop mode acknowledgment

Greg Kroah-Hartman
2019-12-29T17:58:10Z

From: Joakim Zhang <qiangqing.zhang@nxp.com>

commit 048e3a34a2e7669bf475eb56c7345ad9d8d2b8e3 upstream.

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, the MCR[LPM_ACK] bit should be polled for
stop mode acknowledgment, not the acknowledgment from chip level which
is used to gate flexcan clocks.

This patch depends on:

b7603d080ffc ("can: flexcan: add low power enter/exit acknowledgment helper")

Fixes: 5f186c257fa4 (can: flexcan: fix stop mode acknowledgment)
Tested-by: Sean Nyekjaer <sean@geanix.com>
Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Cc: linux-stable <stable@vger.kernel.org> # >= v5.0
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/net/can/flexcan.c | 17 ++---------------
1 file changed, 2 insertions(+), 15 deletions(-)

--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -407,7 +407,6 @@ static void flexcan_enable_wakeup_irq(st
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(&regs->mcr);
@@ -418,36 +417,24 @@ static inline int flexcan_enter_stop_mod
regmap_update_bits(priv->stm.gpr, priv->stm.req_gpr,
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_low_power_enter_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(&regs->mcr);
reg_mcr &= ~FLEXCAN_MCR_SLF_WAK;
priv->write(reg_mcr, &regs->mcr);

- return 0;
+ return flexcan_low_power_exit_ack(priv);
}

static inline void flexcan_error_irq_enable(const struct flexcan_priv *priv)