can: flexcan: poll MCR_LPM_ACK instead of GPR ACK for stop mode acknowledgment

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>

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index 9f3a5e5..94d10ec 100644 (file)
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -435,7 +435,6 @@ 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(&regs->mcr);
@@ -446,36 +445,24 @@ static inline int flexcan_enter_stop_mode(struct flexcan_priv *priv)
        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)