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From: Marc Kleine-Budde <mkl@pengutronix.de>
To: netdev@vger.kernel.org
Cc: davem@davemloft.net, linux-can@vger.kernel.org,
	kernel@pengutronix.de, Sean Nyekjaer <sean@geanix.com>,
	Marc Kleine-Budde <mkl@pengutronix.de>
Subject: [PATCH 3/9] can: tcan4x5x: tcan4x5x_parse_config(): reset device before register access
Date: Thu,  2 Jan 2020 17:09:28 +0100	[thread overview]
Message-ID: <20200102160934.1524-4-mkl@pengutronix.de> (raw)
In-Reply-To: <20200102160934.1524-1-mkl@pengutronix.de>

From: Sean Nyekjaer <sean@geanix.com>

It's a good idea to reset a ip-block/spi device before using it, this
patch will reset the device.

And a generic reset function if needed elsewhere.

Signed-off-by: Sean Nyekjaer <sean@geanix.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/m_can/tcan4x5x.c | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/m_can/tcan4x5x.c b/drivers/net/can/m_can/tcan4x5x.c
index a69476f5aec6..ee22e39f131b 100644
--- a/drivers/net/can/m_can/tcan4x5x.c
+++ b/drivers/net/can/m_can/tcan4x5x.c
@@ -166,6 +166,28 @@ static void tcan4x5x_check_wake(struct tcan4x5x_priv *priv)
 	}
 }
 
+static int tcan4x5x_reset(struct tcan4x5x_priv *priv)
+{
+	int ret = 0;
+
+	if (priv->reset_gpio) {
+		gpiod_set_value(priv->reset_gpio, 1);
+
+		/* tpulse_width minimum 30us */
+		usleep_range(30, 100);
+		gpiod_set_value(priv->reset_gpio, 0);
+	} else {
+		ret = regmap_write(priv->regmap, TCAN4X5X_CONFIG,
+				   TCAN4X5X_SW_RESET);
+		if (ret)
+			return ret;
+	}
+
+	usleep_range(700, 1000);
+
+	return ret;
+}
+
 static int regmap_spi_gather_write(void *context, const void *reg,
 				   size_t reg_len, const void *val,
 				   size_t val_len)
@@ -351,6 +373,7 @@ static int tcan4x5x_disable_wake(struct m_can_classdev *cdev)
 static int tcan4x5x_parse_config(struct m_can_classdev *cdev)
 {
 	struct tcan4x5x_priv *tcan4x5x = cdev->device_data;
+	int ret;
 
 	tcan4x5x->device_wake_gpio = devm_gpiod_get(cdev->dev, "device-wake",
 						    GPIOD_OUT_HIGH);
@@ -366,7 +389,9 @@ static int tcan4x5x_parse_config(struct m_can_classdev *cdev)
 	if (IS_ERR(tcan4x5x->reset_gpio))
 		tcan4x5x->reset_gpio = NULL;
 
-	usleep_range(700, 1000);
+	ret = tcan4x5x_reset(tcan4x5x);
+	if (ret)
+		return ret;
 
 	tcan4x5x->device_state_gpio = devm_gpiod_get_optional(cdev->dev,
 							      "device-state",
-- 
2.24.1

  parent reply	other threads:[~2020-01-02 16:09 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-02 16:09 pull-request: can 2020-01-02 Marc Kleine-Budde
2020-01-02 16:09 ` [PATCH 1/9] can: tcan4x5x: tcan4x5x_can_probe(): get the device out of standby before register access Marc Kleine-Budde
2020-01-02 16:09 ` [PATCH 2/9] can: tcan4x5x: tcan4x5x_can_probe(): turn on the power before parsing the config Marc Kleine-Budde
2020-01-02 16:09 ` Marc Kleine-Budde [this message]
2020-01-02 16:09 ` [PATCH 4/9] can: tcan4x5x: tcan4x5x_parse_config(): Disable the INH pin device-state GPIO is unavailable Marc Kleine-Budde
2020-01-02 16:09 ` [PATCH 5/9] can: tcan4x5x: tcan4x5x_parse_config(): fix inconsistent IS_ERR and PTR_ERR Marc Kleine-Budde
2020-01-02 16:09 ` [PATCH 6/9] can: can_dropped_invalid_skb(): ensure an initialized headroom in outgoing CAN sk_buffs Marc Kleine-Budde
2020-01-02 16:09 ` [PATCH 7/9] can: kvaser_usb: fix interface sanity check Marc Kleine-Budde
2020-01-02 16:09 ` [PATCH 8/9] can: gs_usb: gs_usb_probe(): use descriptors of current altsetting Marc Kleine-Budde
2020-01-02 16:09 ` [PATCH 9/9] can: mscan: mscan_rx_poll(): fix rx path lockup when returning from polling to irq mode Marc Kleine-Budde
2020-01-03  0:41 ` pull-request: can 2020-01-02 David Miller

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