netdev - [PATCH net-next 22/36] can: mcp251xfd: mcp251xfd_chip_softreset_check(): wait for OSC ready before accessing chip

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Date:   Thu, 24 Feb 2022 09:27:12 +0100
From:   Marc Kleine-Budde <mkl@...gutronix.de>
To:     netdev@...r.kernel.org
Cc:     davem@...emloft.net, kuba@...nel.org, linux-can@...r.kernel.org,
        kernel@...gutronix.de, Marc Kleine-Budde <mkl@...gutronix.de>
Subject: [PATCH net-next 22/36] can: mcp251xfd: mcp251xfd_chip_softreset_check(): wait for OSC ready before accessing chip

This patch changes the order of reading the Mode and Oscillator Ready
bits.

Instead of reading the Mode of the chip directly after reset, first
wait for the oscillator to get ready and the chip to fully start up.
Read the Mode after this.

Link: https://lore.kernel.org/all/20220207131047.282110-10-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
---
 .../net/can/spi/mcp251xfd/mcp251xfd-core.c    | 29 ++++++++-----------
 1 file changed, 12 insertions(+), 17 deletions(-)

diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
index f2aac990d285..9b94272da8bc 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
@@ -349,34 +349,29 @@ static int mcp251xfd_chip_softreset_do(const struct mcp251xfd_priv *priv)
 
 static int mcp251xfd_chip_softreset_check(const struct mcp251xfd_priv *priv)
 {
-	u32 osc, osc_reference;
+	u32 osc_reference, osc_mask;
 	u8 mode;
 	int err;
 
-	err = mcp251xfd_chip_get_mode(priv, &mode);
-	if (err)
-		return err;
-
-	if (mode != MCP251XFD_REG_CON_MODE_CONFIG) {
-		netdev_info(priv->ndev,
-			    "Controller not in Config Mode after reset, but in %s Mode (%u).\n",
-			    mcp251xfd_get_mode_str(mode), mode);
-		return -ETIMEDOUT;
-	}
-
+	/* Check for reset defaults of OSC reg.
+	 * This will take care of stabilization period.
+	 */
 	osc_reference = MCP251XFD_REG_OSC_OSCRDY |
 		FIELD_PREP(MCP251XFD_REG_OSC_CLKODIV_MASK,
 			   MCP251XFD_REG_OSC_CLKODIV_10);
+	osc_mask = osc_reference | MCP251XFD_REG_OSC_PLLRDY;
+	err = mcp251xfd_chip_wait_for_osc_ready(priv, osc_reference, osc_mask);
+	if (err)
+		return err;
 
-	/* check reset defaults of OSC reg */
-	err = regmap_read(priv->map_reg, MCP251XFD_REG_OSC, &osc);
+	err = mcp251xfd_chip_get_mode(priv, &mode);
 	if (err)
 		return err;
 
-	if (osc != osc_reference) {
+	if (mode != MCP251XFD_REG_CON_MODE_CONFIG) {
 		netdev_info(priv->ndev,
-			    "Controller failed to reset. osc=0x%08x, reference value=0x%08x.\n",
-			    osc, osc_reference);
+			    "Controller not in Config Mode after reset, but in %s Mode (%u).\n",
+			    mcp251xfd_get_mode_str(mode), mode);
 		return -ETIMEDOUT;
 	}
 
-- 
2.34.1