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From: Gregor Herburger <gregor.herburger@ew.tq-group.com>
Date: Mon, 06 May 2024 07:59:45 +0200
Subject: [PATCH v2 3/6] can: mcp251xfd: move chip sleep mode into runtime
 pm
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Message-Id: <20240506-mcp251xfd-gpio-feature-v2-3-615b16fa8789@ew.tq-group.com>
References: <20240506-mcp251xfd-gpio-feature-v2-0-615b16fa8789@ew.tq-group.com>
In-Reply-To: <20240506-mcp251xfd-gpio-feature-v2-0-615b16fa8789@ew.tq-group.com>
To: Marc Kleine-Budde <mkl@pengutronix.de>, 
 Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>, 
 Thomas Kopp <thomas.kopp@microchip.com>, 
 Vincent Mailhol <mailhol.vincent@wanadoo.fr>, 
 "David S. Miller" <davem@davemloft.net>, Eric Dumazet <edumazet@google.com>, 
 Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>, 
 Rob Herring <robh@kernel.org>, 
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>, 
 Conor Dooley <conor+dt@kernel.org>
Cc: linux-can@vger.kernel.org, netdev@vger.kernel.org, 
 linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, 
 linux@ew.tq-group.com, gregor.herburger@ew.tq-group.com

From: Marc Kleine-Budde <mkl@pengutronix.de>

This is a preparation patch to add GPIO support.

Up to now, the Vdd regulator and the clocks have been managed by
Runtime-PM (on systems without CONFIG_PM these remain permanently
switched on).

During the mcp251xfd_open() callback the mcp251xfd is powered,
soft-reset and configured. In mcp251xfd_stop() the chip is shut down
again. To support the on-chip GPIOs, the chip must be supplied with
power while GPIOs are being requested, even if the networking
interface ist down.

To support this, move the functions mcp251xfd_chip_softreset() and
mcp251xfd_chip_clock_init() from mcp251xfd_chip_start() to
mcp251xfd_runtime_resume(). Instead of setting the controller to sleep
mode in mcp251xfd_chip_stop(), bring it into configuration mode. This
way it doesn't take part in bus activity and doesn't enter sleep mode.

Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c | 99 ++++++++++++++++----------
 1 file changed, 61 insertions(+), 38 deletions(-)

diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
index 4ae201426a46..4739ad80ef2a 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
@@ -745,21 +745,13 @@ static void mcp251xfd_chip_stop(struct mcp251xfd_priv *priv,
 	mcp251xfd_chip_interrupts_disable(priv);
 	mcp251xfd_chip_rx_int_disable(priv);
 	mcp251xfd_timestamp_stop(priv);
-	mcp251xfd_chip_sleep(priv);
+	mcp251xfd_chip_set_mode(priv, MCP251XFD_REG_CON_MODE_CONFIG);
 }
 
 static int mcp251xfd_chip_start(struct mcp251xfd_priv *priv)
 {
 	int err;
 
-	err = mcp251xfd_chip_softreset(priv);
-	if (err)
-		goto out_chip_stop;
-
-	err = mcp251xfd_chip_clock_init(priv);
-	if (err)
-		goto out_chip_stop;
-
 	err = mcp251xfd_chip_timestamp_init(priv);
 	if (err)
 		goto out_chip_stop;
@@ -1602,8 +1594,11 @@ static int mcp251xfd_open(struct net_device *ndev)
 		return err;
 
 	err = pm_runtime_resume_and_get(ndev->dev.parent);
-	if (err)
+	if (err) {
+		if (err == -ETIMEDOUT || err == -ENODEV)
+			pm_runtime_set_suspended(ndev->dev.parent);
 		goto out_close_candev;
+	}
 
 	err = mcp251xfd_ring_alloc(priv);
 	if (err)
@@ -1872,53 +1867,53 @@ static int mcp251xfd_register(struct mcp251xfd_priv *priv)
 	struct net_device *ndev = priv->ndev;
 	int err;
 
+	mcp251xfd_register_quirks(priv);
+
 	err = mcp251xfd_clks_and_vdd_enable(priv);
 	if (err)
 		return err;
 
+	err = mcp251xfd_chip_softreset(priv);
+	if (err == -ENODEV)
+		goto out_clks_and_vdd_disable;
+	if (err)
+		goto out_chip_sleep;
+
+	err = mcp251xfd_chip_clock_init(priv);
+	if (err == -ENODEV)
+		goto out_clks_and_vdd_disable;
+	if (err)
+		goto out_chip_sleep;
+
 	pm_runtime_get_noresume(ndev->dev.parent);
 	err = pm_runtime_set_active(ndev->dev.parent);
 	if (err)
 		goto out_runtime_put_noidle;
 	pm_runtime_enable(ndev->dev.parent);
 
-	mcp251xfd_register_quirks(priv);
-
-	err = mcp251xfd_chip_softreset(priv);
-	if (err == -ENODEV)
-		goto out_runtime_disable;
-	if (err)
-		goto out_chip_sleep;
-
-	err = mcp251xfd_chip_clock_init(priv);
-	if (err == -ENODEV)
-		goto out_runtime_disable;
-	if (err)
-		goto out_chip_sleep;
-
 	err = mcp251xfd_register_chip_detect(priv);
 	if (err)
-		goto out_chip_sleep;
+		goto out_runtime_disable;
 
 	err = mcp251xfd_register_check_rx_int(priv);
 	if (err)
-		goto out_chip_sleep;
+		goto out_runtime_disable;
 
 	mcp251xfd_ethtool_init(priv);
 
 	err = register_candev(ndev);
 	if (err)
-		goto out_chip_sleep;
+		goto out_runtime_disable;
 
 	err = mcp251xfd_register_done(priv);
 	if (err)
 		goto out_unregister_candev;
 
-	/* Put controller into sleep mode and let pm_runtime_put()
-	 * disable the clocks and vdd. If CONFIG_PM is not enabled,
-	 * the clocks and vdd will stay powered.
+	/* Put controller into Config mode and let pm_runtime_put()
+	 * put in sleep mode, disable the clocks and vdd. If CONFIG_PM
+	 * is not enabled, the clocks and vdd will stay powered.
 	 */
-	err = mcp251xfd_chip_sleep(priv);
+	err = mcp251xfd_chip_set_mode(priv, MCP251XFD_REG_CON_MODE_CONFIG);
 	if (err)
 		goto out_unregister_candev;
 
@@ -1928,12 +1923,13 @@ static int mcp251xfd_register(struct mcp251xfd_priv *priv)
 
 out_unregister_candev:
 	unregister_candev(ndev);
-out_chip_sleep:
-	mcp251xfd_chip_sleep(priv);
 out_runtime_disable:
 	pm_runtime_disable(ndev->dev.parent);
 out_runtime_put_noidle:
 	pm_runtime_put_noidle(ndev->dev.parent);
+out_chip_sleep:
+	mcp251xfd_chip_sleep(priv);
+out_clks_and_vdd_disable:
 	mcp251xfd_clks_and_vdd_disable(priv);
 
 	return err;
@@ -1945,10 +1941,12 @@ static inline void mcp251xfd_unregister(struct mcp251xfd_priv *priv)
 
 	unregister_candev(ndev);
 
-	if (pm_runtime_enabled(ndev->dev.parent))
+	if (pm_runtime_enabled(ndev->dev.parent)) {
 		pm_runtime_disable(ndev->dev.parent);
-	else
+	} else {
+		mcp251xfd_chip_sleep(priv);
 		mcp251xfd_clks_and_vdd_disable(priv);
+	}
 }
 
 static const struct of_device_id mcp251xfd_of_match[] = {
@@ -2175,16 +2173,41 @@ static void mcp251xfd_remove(struct spi_device *spi)
 
 static int __maybe_unused mcp251xfd_runtime_suspend(struct device *device)
 {
-	const struct mcp251xfd_priv *priv = dev_get_drvdata(device);
+	struct mcp251xfd_priv *priv = dev_get_drvdata(device);
 
+	mcp251xfd_chip_sleep(priv);
 	return mcp251xfd_clks_and_vdd_disable(priv);
 }
 
 static int __maybe_unused mcp251xfd_runtime_resume(struct device *device)
 {
-	const struct mcp251xfd_priv *priv = dev_get_drvdata(device);
+	struct mcp251xfd_priv *priv = dev_get_drvdata(device);
+	int err;
 
-	return mcp251xfd_clks_and_vdd_enable(priv);
+	err = mcp251xfd_clks_and_vdd_enable(priv);
+	if (err)
+		return err;
+
+	err = mcp251xfd_chip_softreset(priv);
+	if (err == -ENODEV)
+		goto out_clks_and_vdd_disable;
+	if (err)
+		goto out_chip_sleep;
+
+	err = mcp251xfd_chip_clock_init(priv);
+	if (err == -ENODEV)
+		goto out_clks_and_vdd_disable;
+	if (err)
+		goto out_chip_sleep;
+
+	return 0;
+
+out_chip_sleep:
+	mcp251xfd_chip_sleep(priv);
+out_clks_and_vdd_disable:
+	mcp251xfd_clks_and_vdd_disable(priv);
+
+	return err;
 }
 
 static const struct dev_pm_ops mcp251xfd_pm_ops = {

-- 
2.34.1