wilc1000: Convert module-global "isinit" to device-specific variable

Move static "isinit" variable to wilc_spi structure to allow multiple
WILC1000 devices per machine.
Signed-off-by: David Mosberger-Tang <davidm@egauge.net>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210828151346.3012697-1-davidm@egauge.net

drivers/net/wireless/microchip/wilc1000/spi.c

@@ -39,6 +39,7 @@ MODULE_PARM_DESC(enable_crc16,
 #define WILC_SPI_RSP_HDR_EXTRA_DATA	8
 
 struct wilc_spi {
+	bool isinit;		/* true if SPI protocol has been configured */
 	bool probing_crc;	/* true if we're probing chip's CRC config */
 	bool crc7_enabled;	/* true if crc7 is currently enabled */
 	bool crc16_enabled;	/* true if crc16 is currently enabled */
@@ -908,15 +909,15 @@ static int wilc_spi_init(struct wilc *wilc, bool resume)
 	struct wilc_spi *spi_priv = wilc->bus_data;
 	u32 reg;
 	u32 chipid;
-	static int isinit;
 	int ret, i;
 
-	if (isinit) {
+	if (spi_priv->isinit) {
+		/* Confirm we can read chipid register without error: */
 		ret = wilc_spi_read_reg(wilc, WILC_CHIPID, &chipid);
-		if (ret)
-			dev_err(&spi->dev, "Fail cmd read chip id...\n");
+		if (ret == 0)
+			return 0;
 
-		return ret;
+		dev_err(&spi->dev, "Fail cmd read chip id...\n");
 	}
 
 	/*
@@ -974,7 +975,7 @@ static int wilc_spi_init(struct wilc *wilc, bool resume)
 	spi_priv->probing_crc = false;
 
 	/*
-	 * make sure can read back chip id correctly
+	 * make sure can read chip id without protocol error
 	 */
 	ret = wilc_spi_read_reg(wilc, WILC_CHIPID, &chipid);
 	if (ret) {
@@ -982,7 +983,7 @@ static int wilc_spi_init(struct wilc *wilc, bool resume)
 		return ret;
 	}
 
-	isinit = 1;
+	spi_priv->isinit = true;
 
 	return 0;
 }