driver: flash: mcux_flexspi_nor: Fix for is25lpxxxd chips

IS25LPXXXD uses the same jedec-id as IS25LPXXX, but the latter has
an extended read register, similar to IS25WPXXX. This change will
attempt to read the extended read register to determine what the
appropriate initialization value for read register should be.

Signed-off-by: John Barbero Unenge <git@lsrkttn.com>

Author: JBarberU

drivers/flash/flash_mcux_flexspi_nor.c

@@ -943,37 +943,72 @@ static int flash_flexspi_nor_sfdp_read(const struct device *dev,
 
 #endif
 
-/* Helper to configure IS25 flash, by clearing read param bits */
-static int flash_flexspi_nor_is25_clear_read_param(struct flash_flexspi_nor_data *data,
-			uint32_t (*flexspi_lut)[MEMC_FLEXSPI_CMD_PER_SEQ],
-			uint32_t *read_params)
+/* Helper to configure IS25 flash */
+static int
+flash_flexspi_nor_is25_clear_dummy_cycles(struct flash_flexspi_nor_data *data,
+					  uint32_t (*flexspi_lut)[MEMC_FLEXSPI_CMD_PER_SEQ])
 {
 	int ret;
-	/* Install Set Read Parameters (Volatile) command */
+
+	const flexspi_device_config_t config = {
+		.flexspiRootClk = MHZ(50),
+		.flashSize = FLEXSPI_FLSHCR0_FLSHSZ_MASK, /* Max flash size */
+		.ARDSeqNumber = 1,
+		.ARDSeqIndex = READ,
+	};
+
 	flexspi_transfer_t transfer = {
 		.deviceAddress = 0,
 		.port = data->port,
 		.seqIndex = SCRATCH_CMD,
 		.SeqNumber = 1,
-		.data = read_params,
 		.dataSize = 1,
-		.cmdType = kFLEXSPI_Write,
-	};
-	flexspi_device_config_t config = {
-		.flexspiRootClk = MHZ(50),
-		.flashSize = FLEXSPI_FLSHCR0_FLSHSZ_MASK, /* Max flash size */
-		.ARDSeqNumber = 1,
-		.ARDSeqIndex = READ,
 	};
 
-	flexspi_lut[SCRATCH_CMD][0] = FLEXSPI_LUT_SEQ(
-			kFLEXSPI_Command_SDR, kFLEXSPI_1PAD, 0xC0,
-			kFLEXSPI_Command_WRITE_SDR, kFLEXSPI_1PAD, 0x1);
-	ret = memc_flexspi_set_device_config(&data->controller,
-				&config,
-				(uint32_t *)flexspi_lut,
-				FLEXSPI_INSTR_END * MEMC_FLEXSPI_CMD_PER_SEQ,
-				data->port);
+	/*
+	 * Get Extended Read Parameters (Non-Volatile) command (RDERP, 81h)
+	 *
+	 * This is done to distinguish between an IS25LPXXX and IS25LPXXXD since
+	 * the former uses the read parameters (SRPV) to set drive strength and
+	 * dummy cycles, while IS25LPXXXD uses extended read parameters (SERPV)
+	 * for drive strength and read parameters (SRPV) for dummy cycles.
+	 */
+	uint32_t resp_data;
+
+	transfer.data = &resp_data;
+	transfer.cmdType = kFLEXSPI_Read;
+
+	flexspi_lut[SCRATCH_CMD][0] =
+		FLEXSPI_LUT_SEQ(kFLEXSPI_Command_SDR, kFLEXSPI_1PAD, 0x81,
+				kFLEXSPI_Command_READ_SDR, kFLEXSPI_1PAD, 0x1);
+	ret = memc_flexspi_set_device_config(&data->controller, &config, (uint32_t *)flexspi_lut,
+					     FLEXSPI_INSTR_END * MEMC_FLEXSPI_CMD_PER_SEQ,
+					     data->port);
+
+	if (ret < 0) {
+		return ret;
+	}
+
+	ret = memc_flexspi_transfer(&data->controller, &transfer);
+
+	/*
+	 * Check that EB[7:4] is not all zero and that EB[0] (WIP)
+	 * is not 1, which should catch a chip responding to an
+	 * unsupported 81h command with either 0x00 or 0xFF
+	 */
+	const int has_extended_read_reg = resp_data & 0xF0 && !(resp_data & 0x01);
+	uint32_t read_params = has_extended_read_reg ? 0 : 0xE0U;
+
+	/* Switch over to writing read_params (SRPV, C0h) */
+	transfer.cmdType = kFLEXSPI_Write;
+	transfer.data = &read_params;
+
+	flexspi_lut[SCRATCH_CMD][0] =
+		FLEXSPI_LUT_SEQ(kFLEXSPI_Command_SDR, kFLEXSPI_1PAD, 0xC0,
+				kFLEXSPI_Command_WRITE_SDR, kFLEXSPI_1PAD, 0x1);
+	ret = memc_flexspi_set_device_config(&data->controller, &config, (uint32_t *)flexspi_lut,
+					     FLEXSPI_INSTR_END * MEMC_FLEXSPI_CMD_PER_SEQ,
+					     data->port);
 	if (ret < 0) {
 		return ret;
 	}
@@ -986,7 +1021,6 @@ static int flash_flexspi_nor_check_jedec(struct flash_flexspi_nor_data *data,
 {
 	int ret;
 	uint32_t vendor_id;
-	uint32_t read_params;
 
 	ret = flash_flexspi_nor_read_id_helper(data, (uint8_t *)&vendor_id);
 	if (ret < 0) {
@@ -995,31 +1029,17 @@ static int flash_flexspi_nor_check_jedec(struct flash_flexspi_nor_data *data,
 
 	/* Switch on manufacturer and vendor ID */
 	switch (vendor_id & 0xFFFFFF) {
-	case 0x16609d: /* IS25LP032 flash, needs P[4:3] cleared with same method as IS25WP */
+	case 0x16609d: /* IS25LP032 */
 	case 0x17609d: /* IS25LP064 */
 	case 0x18609d: /* IS25LP128 */
-		read_params = 0xE0U;
-		ret = flash_flexspi_nor_is25_clear_read_param(data, flexspi_lut, &read_params);
-		if (ret < 0) {
-			while (1) {
-				/*
-				 * Spin here, this flash won't configure correctly.
-				 * We can't print a warning, as we are unlikely to
-				 * be able to XIP at this point.
-				 */
-			}
-		}
-		/* Still return an error- we want the JEDEC configuration to run */
-		return -ENOTSUP;
 	case 0x16709d: /* IS25WP032 */
 	case 0x17709d: /* IS25WP064 */
 	case 0x18709d: /* IS25WP128 */
 		/*
-		 * IS25WP flash. We can support this flash with the JEDEC probe,
-		 * but we need to insure P[6:3] are at the default value
+		 * We can support this flash with the JEDEC probe, but we need to
+		 * ensure Dummy Cycles are at the default value
 		 */
-		read_params = 0;
-		ret = flash_flexspi_nor_is25_clear_read_param(data, flexspi_lut, &read_params);
+		ret = flash_flexspi_nor_is25_clear_dummy_cycles(data, flexspi_lut);
 		if (ret < 0) {
 			while (1) {
 				/*