[PATCH 5.4 388/434] can: flexcan: add low power enter/exit acknowledgment helper

Greg Kroah-Hartman
2019-12-29T18:00:53Z

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

[ Upstream commit b7603d080ffcf8689ec91ca300caf84d8dbed317 ]

The MCR[LPMACK] read-only bit indicates that FlexCAN is in a lower-power
mode (Disabled mode, Doze mode, Stop mode).

The CPU can poll this bit to know when FlexCAN has actually entered low
power mode. The low power enter/exit acknowledgment helper will reduce
code duplication for disabled mode, doze mode and stop mode.

Tested-by: Sean Nyekjaer <sean@geanix.com>
Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/can/flexcan.c | 46 +++++++++++++++++++++++++--------------
1 file changed, 30 insertions(+), 16 deletions(-)

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index 99b3492ea130..e5c207ad3c77 100644
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -389,6 +389,34 @@ 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_low_power_enter_ack(struct flexcan_priv *priv)
+{
+ struct flexcan_regs __iomem *regs = priv->regs;
+ unsigned int timeout = FLEXCAN_TIMEOUT_US / 10;
+
+ while (timeout-- && !(priv->read(&regs->mcr) & FLEXCAN_MCR_LPM_ACK))
+ udelay(10);
+
+ if (!(priv->read(&regs->mcr) & FLEXCAN_MCR_LPM_ACK))
+ return -ETIMEDOUT;
+
+ return 0;
+}
+
+static int flexcan_low_power_exit_ack(struct flexcan_priv *priv)
+{
+ struct flexcan_regs __iomem *regs = priv->regs;
+ unsigned int timeout = FLEXCAN_TIMEOUT_US / 10;
+
+ while (timeout-- && (priv->read(&regs->mcr) & FLEXCAN_MCR_LPM_ACK))
+ udelay(10);
+
+ if (priv->read(&regs->mcr) & FLEXCAN_MCR_LPM_ACK)
+ return -ETIMEDOUT;
+
+ return 0;
+}
+
static void flexcan_enable_wakeup_irq(struct flexcan_priv *priv, bool enable)
{
struct flexcan_regs __iomem *regs = priv->regs;
@@ -493,39 +521,25 @@ 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(&regs->mcr);
reg &= ~FLEXCAN_MCR_MDIS;
priv->write(reg, &regs->mcr);

- while (timeout-- && (priv->read(&regs->mcr) & FLEXCAN_MCR_LPM_ACK))
- udelay(10);
-
- if (priv->read(&regs->mcr) & FLEXCAN_MCR_LPM_ACK)
- return -ETIMEDOUT;
-
- return 0;
+ return flexcan_low_power_exit_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(&regs->mcr);
reg |= FLEXCAN_MCR_MDIS;
priv->write(reg, &regs->mcr);

- while (timeout-- && !(priv->read(&regs->mcr) & FLEXCAN_MCR_LPM_ACK))
- udelay(10);
-
- if (!(priv->read(&regs->mcr) & FLEXCAN_MCR_LPM_ACK))
- return -ETIMEDOUT;
-
- return 0;
+ return flexcan_low_power_enter_ack(priv);
}

static int flexcan_chip_freeze(struct flexcan_priv *priv)
--
2.20.1