wilc1000: Support chip sleep over SPI

chip_allow_sleep() only supported wakeup via SDIO, which made the
driver unusable over SPI.  This code is a straight forward port from
the driver in the linux-at91 repository.
Signed-off-by: David Mosberger-Tang <davidm@egauge.net>
Acked-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210224033317.1507603-1-davidm@egauge.net

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

@@ -552,12 +552,60 @@ static struct rxq_entry_t *wilc_wlan_rxq_remove(struct wilc *wilc)
 void chip_allow_sleep(struct wilc *wilc)
 {
 	u32 reg = 0;
+	const struct wilc_hif_func *hif_func = wilc->hif_func;
+	u32 wakeup_reg, wakeup_bit;
+	u32 to_host_from_fw_reg, to_host_from_fw_bit;
+	u32 from_host_to_fw_reg, from_host_to_fw_bit;
+	u32 trials = 100;
+	int ret;
 
-	wilc->hif_func->hif_read_reg(wilc, WILC_SDIO_WAKEUP_REG, &reg);
+	if (wilc->io_type == WILC_HIF_SDIO) {
+		wakeup_reg = WILC_SDIO_WAKEUP_REG;
+		wakeup_bit = WILC_SDIO_WAKEUP_BIT;
+		from_host_to_fw_reg = WILC_SDIO_HOST_TO_FW_REG;
+		from_host_to_fw_bit = WILC_SDIO_HOST_TO_FW_BIT;
+		to_host_from_fw_reg = WILC_SDIO_FW_TO_HOST_REG;
+		to_host_from_fw_bit = WILC_SDIO_FW_TO_HOST_BIT;
+	} else {
+		wakeup_reg = WILC_SPI_WAKEUP_REG;
+		wakeup_bit = WILC_SPI_WAKEUP_BIT;
+		from_host_to_fw_reg = WILC_SPI_HOST_TO_FW_REG;
+		from_host_to_fw_bit = WILC_SPI_HOST_TO_FW_BIT;
+		to_host_from_fw_reg = WILC_SPI_FW_TO_HOST_REG;
+		to_host_from_fw_bit = WILC_SPI_FW_TO_HOST_BIT;
+	}
 
-	wilc->hif_func->hif_write_reg(wilc, WILC_SDIO_WAKEUP_REG,
-				      reg & ~WILC_SDIO_WAKEUP_BIT);
-	wilc->hif_func->hif_write_reg(wilc, WILC_SDIO_HOST_TO_FW_REG, 0);
+	while (trials--) {
+		ret = hif_func->hif_read_reg(wilc, to_host_from_fw_reg, &reg);
+		if (ret)
+			return;
+		if ((reg & to_host_from_fw_bit) == 0)
+			break;
+	}
+	if (!trials)
+		pr_warn("FW not responding\n");
+
+	/* Clear bit 1 */
+	ret = hif_func->hif_read_reg(wilc, wakeup_reg, &reg);
+	if (ret)
+		return;
+	if (reg & wakeup_bit) {
+		reg &= ~wakeup_bit;
+		ret = hif_func->hif_write_reg(wilc, wakeup_reg, reg);
+		if (ret)
+			return;
+	}
+
+	ret = hif_func->hif_read_reg(wilc, from_host_to_fw_reg, &reg);
+	if (ret)
+		return;
+	if (reg & from_host_to_fw_bit) {
+		reg &= ~from_host_to_fw_bit;
+		ret = hif_func->hif_write_reg(wilc, from_host_to_fw_reg, reg);
+		if (ret)
+			return;
+
+	}
 }
 EXPORT_SYMBOL_GPL(chip_allow_sleep);
 

drivers/net/wireless/microchip/wilc1000/wlan.h

@@ -97,6 +97,12 @@
 #define WILC_SPI_WAKEUP_REG		0x1
 #define WILC_SPI_WAKEUP_BIT		BIT(1)
 
+#define WILC_SPI_HOST_TO_FW_REG		0x0b
+#define WILC_SPI_HOST_TO_FW_BIT		BIT(0)
+
+#define WILC_SPI_FW_TO_HOST_REG		0x10
+#define WILC_SPI_FW_TO_HOST_BIT		BIT(0)
+
 #define WILC_SPI_PROTOCOL_OFFSET	(WILC_SPI_PROTOCOL_CONFIG - \
 					 WILC_SPI_REG_BASE)