[PATCH V6 2/2] can: flexcan: add self wakeup support

[Joakim Zhang]

From: Aisheng Dong <aisheng.dong@xxxxxxx>

If wakeup is enabled, enter stop mode, else enter disabled mode. Self wake
can only work on stop mode.

Starting from IMX6, the flexcan stop mode control bits is SoC specific,
move it out of IP driver and parse it from devicetree.

Signed-off-by: Aisheng Dong <aisheng.dong@xxxxxxx>
Signed-off-by: Joakim Zhang <qiangqing.zhang@xxxxxxx>
---
ChangeLog:
V1->V2:
	*add a vendor prefix in property (stop-mode -> fsl,stop-mode).
V2->V3:
	*add FLEXCAN_QUIRK_SETUP_STOP_MODE quirk.
	*rename function.
	*fix system can't be wakeuped during suspend.
V3->V4:
	*normalize the code following Aisheng Dong's comments.
V4->V5:
	*move enable/disable self wakeup feature into
	 enter/exit_stop_mode() function.
V5->V6:
	*exchange the order of flexcan_enable_wakeup_irq(priv, false)
	 and disable_irq_wake(dev->irq).
---
 drivers/net/can/flexcan.c | 172 ++++++++++++++++++++++++++++++++++++--
 1 file changed, 163 insertions(+), 9 deletions(-)

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index 8e972ef08637..da08a8c113d2 100644
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -19,11 +19,14 @@
 #include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
+#include <linux/mfd/syscon.h>
+#include <linux/mfd/syscon/imx6q-iomuxc-gpr.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/regulator/consumer.h>
+#include <linux/regmap.h>
 
 #define DRV_NAME			"flexcan"
 
@@ -131,7 +134,8 @@
 	(FLEXCAN_ESR_ERR_BUS | FLEXCAN_ESR_ERR_STATE)
 #define FLEXCAN_ESR_ALL_INT \
 	(FLEXCAN_ESR_TWRN_INT | FLEXCAN_ESR_RWRN_INT | \
-	 FLEXCAN_ESR_BOFF_INT | FLEXCAN_ESR_ERR_INT)
+	FLEXCAN_ESR_BOFF_INT | FLEXCAN_ESR_ERR_INT | \
+	FLEXCAN_ESR_WAK_INT)
 
 /* FLEXCAN interrupt flag register (IFLAG) bits */
 /* Errata ERR005829 step7: Reserve first valid MB */
@@ -190,6 +194,7 @@
 #define FLEXCAN_QUIRK_USE_OFF_TIMESTAMP	BIT(5) /* Use timestamp based offloading */
 #define FLEXCAN_QUIRK_BROKEN_PERR_STATE	BIT(6) /* No interrupt for error passive */
 #define FLEXCAN_QUIRK_DEFAULT_BIG_ENDIAN	BIT(7) /* default to BE register access */
+#define FLEXCAN_QUIRK_SETUP_STOP_MODE		BIT(8) /* Setup stop mode to support wakeup */
 
 /* Structure of the message buffer */
 struct flexcan_mb {
@@ -254,6 +259,14 @@ struct flexcan_devtype_data {
 	u32 quirks;		/* quirks needed for different IP cores */
 };
 
+struct flexcan_stop_mode {
+	struct regmap *gpr;
+	u8 req_gpr;
+	u8 req_bit;
+	u8 ack_gpr;
+	u8 ack_bit;
+};
+
 struct flexcan_priv {
 	struct can_priv can;
 	struct can_rx_offload offload;
@@ -270,6 +283,7 @@ struct flexcan_priv {
 	struct clk *clk_per;
 	const struct flexcan_devtype_data *devtype_data;
 	struct regulator *reg_xceiver;
+	struct flexcan_stop_mode stm;
 
 	/* Read and Write APIs */
 	u32 (*read)(void __iomem *addr);
@@ -293,7 +307,8 @@ static const struct flexcan_devtype_data fsl_imx28_devtype_data = {
 
 static const struct flexcan_devtype_data fsl_imx6q_devtype_data = {
 	.quirks = FLEXCAN_QUIRK_DISABLE_RXFG | FLEXCAN_QUIRK_ENABLE_EACEN_RRS |
-		FLEXCAN_QUIRK_USE_OFF_TIMESTAMP | FLEXCAN_QUIRK_BROKEN_PERR_STATE,
+		FLEXCAN_QUIRK_USE_OFF_TIMESTAMP | FLEXCAN_QUIRK_BROKEN_PERR_STATE |
+		FLEXCAN_QUIRK_SETUP_STOP_MODE,
 };
 
 static const struct flexcan_devtype_data fsl_vf610_devtype_data = {
@@ -353,6 +368,49 @@ static inline void flexcan_write_le(u32 val, void __iomem *addr)
 	iowrite32(val, addr);
 }
 
+static void flexcan_enable_wakeup_irq(struct flexcan_priv *priv, bool enable)
+{
+	struct flexcan_regs __iomem *regs = priv->regs;
+	u32 reg_mcr;
+
+	reg_mcr = priv->read(&regs->mcr);
+
+	if (enable)
+		reg_mcr |= FLEXCAN_MCR_WAK_MSK;
+	else
+		reg_mcr &= ~FLEXCAN_MCR_WAK_MSK;
+
+	priv->write(reg_mcr, &regs->mcr);
+}
+
+static inline void flexcan_enter_stop_mode(struct flexcan_priv *priv)
+{
+	struct flexcan_regs __iomem *regs = priv->regs;
+	u32 reg_mcr;
+
+	reg_mcr = priv->read(&regs->mcr);
+	reg_mcr |= FLEXCAN_MCR_SLF_WAK;
+	priv->write(reg_mcr, &regs->mcr);
+
+	/* enable stop request */
+	regmap_update_bits(priv->stm.gpr, priv->stm.req_gpr,
+			   1 << priv->stm.req_bit, 1 << priv->stm.req_bit);
+}
+
+static inline void flexcan_exit_stop_mode(struct flexcan_priv *priv)
+{
+	struct flexcan_regs __iomem *regs = priv->regs;
+	u32 reg_mcr;
+
+	/* remove stop request */
+	regmap_update_bits(priv->stm.gpr, priv->stm.req_gpr,
+			   1 << priv->stm.req_bit, 0);
+
+	reg_mcr = priv->read(&regs->mcr);
+	reg_mcr &= ~FLEXCAN_MCR_SLF_WAK;
+	priv->write(reg_mcr, &regs->mcr);
+}
+
 static inline void flexcan_error_irq_enable(const struct flexcan_priv *priv)
 {
 	struct flexcan_regs __iomem *regs = priv->regs;
@@ -1244,6 +1302,57 @@ static void unregister_flexcandev(struct net_device *dev)
 	unregister_candev(dev);
 }
 
+static int flexcan_setup_stop_mode(struct platform_device *pdev)
+{
+	struct net_device *dev = platform_get_drvdata(pdev);
+	struct device_node *np = pdev->dev.of_node;
+	struct device_node *gpr_np;
+	struct flexcan_priv *priv;
+	phandle phandle;
+	u32 out_val[5];
+	int ret;
+
+	if (!np)
+		return -EINVAL;
+
+	/* stop mode property format is:
+	 * <&gpr req_gpr req_bit ack_gpr ack_bit>.
+	 */
+	ret = of_property_read_u32_array(np, "fsl,stop-mode", out_val, 5);
+	if (ret) {
+		dev_dbg(&pdev->dev, "no stop-mode property\n");
+		return ret;
+	}
+	phandle = *out_val;
+
+	gpr_np = of_find_node_by_phandle(phandle);
+	if (!gpr_np) {
+		dev_dbg(&pdev->dev, "could not find gpr node by phandle\n");
+		return PTR_ERR(gpr_np);
+	}
+
+	priv = netdev_priv(dev);
+	priv->stm.gpr = syscon_node_to_regmap(gpr_np);
+	of_node_put(gpr_np);
+	if (IS_ERR(priv->stm.gpr)) {
+		dev_dbg(&pdev->dev, "could not find gpr regmap\n");
+		return PTR_ERR(priv->stm.gpr);
+	}
+
+	priv->stm.req_gpr = out_val[1];
+	priv->stm.req_bit = out_val[2];
+	priv->stm.ack_gpr = out_val[3];
+	priv->stm.ack_bit = out_val[4];
+
+	dev_dbg(&pdev->dev, "gpr %s req_gpr 0x%x req_bit %u ack_gpr 0x%x ack_bit %u\n",
+		gpr_np->full_name, priv->stm.req_gpr, priv->stm.req_bit, priv->stm.ack_gpr,
+		priv->stm.ack_bit);
+
+	device_set_wakeup_capable(&pdev->dev, true);
+
+	return 0;
+}
+
 static const struct of_device_id flexcan_of_match[] = {
 	{ .compatible = "fsl,imx6q-flexcan", .data = &fsl_imx6q_devtype_data, },
 	{ .compatible = "fsl,imx28-flexcan", .data = &fsl_imx28_devtype_data, },
@@ -1396,6 +1505,12 @@ static int flexcan_probe(struct platform_device *pdev)
 
 	devm_can_led_init(dev);
 
+	if (priv->devtype_data->quirks & FLEXCAN_QUIRK_SETUP_STOP_MODE) {
+		err = flexcan_setup_stop_mode(pdev);
+		if (err)
+			dev_dbg(&pdev->dev, "failed to setup stop-mode\n");
+	}
+
 	dev_info(&pdev->dev, "device registered (reg_base=%p, irq=%d)\n",
 		 priv->regs, dev->irq);
 
@@ -1426,9 +1541,17 @@ static int __maybe_unused flexcan_suspend(struct device *device)
 	int err;
 
 	if (netif_running(dev)) {
-		err = flexcan_chip_disable(priv);
-		if (err)
-			return err;
+		/* if wakeup is enabled, enter stop mode
+		 * else enter disabled mode.
+		 */
+		if (device_may_wakeup(device)) {
+			enable_irq_wake(dev->irq);
+			flexcan_enter_stop_mode(priv);
+		} else {
+			err = flexcan_chip_disable(priv);
+			if (err)
+				return err;
+		}
 		netif_stop_queue(dev);
 		netif_device_detach(dev);
 	}
@@ -1447,14 +1570,45 @@ static int __maybe_unused flexcan_resume(struct device *device)
 	if (netif_running(dev)) {
 		netif_device_attach(dev);
 		netif_start_queue(dev);
-		err = flexcan_chip_enable(priv);
-		if (err)
-			return err;
+		if (device_may_wakeup(device)) {
+			disable_irq_wake(dev->irq);
+		} else {
+			err = flexcan_chip_enable(priv);
+			if (err)
+				return err;
+		}
 	}
 	return 0;
 }
 
-static SIMPLE_DEV_PM_OPS(flexcan_pm_ops, flexcan_suspend, flexcan_resume);
+static int __maybe_unused flexcan_noirq_suspend(struct device *device)
+{
+	struct net_device *dev = dev_get_drvdata(device);
+	struct flexcan_priv *priv = netdev_priv(dev);
+
+	if (netif_running(dev) && device_may_wakeup(device))
+		flexcan_enable_wakeup_irq(priv, true);
+
+	return 0;
+}
+
+static int __maybe_unused flexcan_noirq_resume(struct device *device)
+{
+	struct net_device *dev = dev_get_drvdata(device);
+	struct flexcan_priv *priv = netdev_priv(dev);
+
+	if (netif_running(dev) && device_may_wakeup(device)) {
+		flexcan_enable_wakeup_irq(priv, false);
+		flexcan_exit_stop_mode(priv);
+	}
+
+	return 0;
+}
+
+static const struct dev_pm_ops flexcan_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(flexcan_suspend, flexcan_resume)
+	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(flexcan_noirq_suspend, flexcan_noirq_resume)
+};
 
 static struct platform_driver flexcan_driver = {
 	.driver = {
-- 
2.17.1