can: mcp251xfd: mcp251xfd_chip_clock_init(): prepare for PLL support, wait for OSC ready

This patch prepares the mcp251xfd_chip_clock_init() function for PLL
support.

If the PLL is needed is must be switched on after chip reset. This
should be done in the mcp251xfd_chip_clock_init() function. Prepare
this function to wait for the OSC and PLL to be ready.

Link: https://lore.kernel.org/all/20220207131047.282110-14-mkl@pengutronix.deSigned-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c

@@ -429,7 +429,7 @@ static int mcp251xfd_chip_softreset(const struct mcp251xfd_priv *priv)
 
 static int mcp251xfd_chip_clock_init(const struct mcp251xfd_priv *priv)
 {
-	u32 osc;
+	u32 osc, osc_reference, osc_mask;
 	int err;
 
 	/* Activate Low Power Mode on Oscillator Disable. This only
@@ -439,10 +439,17 @@ static int mcp251xfd_chip_clock_init(const struct mcp251xfd_priv *priv)
 	osc = MCP251XFD_REG_OSC_LPMEN |
 		FIELD_PREP(MCP251XFD_REG_OSC_CLKODIV_MASK,
 			   MCP251XFD_REG_OSC_CLKODIV_10);
+	osc_reference = MCP251XFD_REG_OSC_OSCRDY;
+	osc_mask = MCP251XFD_REG_OSC_OSCRDY | MCP251XFD_REG_OSC_PLLRDY;
+
 	err = regmap_write(priv->map_reg, MCP251XFD_REG_OSC, osc);
 	if (err)
 		return err;
 
+	err = mcp251xfd_chip_wait_for_osc_ready(priv, osc_reference, osc_mask);
+	if (err)
+		return err;
+
 	return 0;
 }