[nrf fromlist] drivers: flash: nrf_qspi_nor: clean up lock/unlock idioms

Having a completion wait function release a lock internally only when
the operation fails is confusing.  Remove that feature, and make the
lock and unlock operations explicit and paired.

This makes it much more clear how to properly handle transactions that
require multiple calls to the HAL.

Signed-off-by: Peter Bigot <[email protected]>
Signed-off-by: Sigvart Hovland <[email protected]>
(cherry picked from commit 35d3836)

Author: pabigot

drivers/flash/nrf_qspi_nor.c

@@ -248,8 +248,6 @@ static inline void qspi_wait_for_completion(struct device *dev,
 
 	if (res == NRFX_SUCCESS) {
 		k_sem_take(&dev_data->sync, K_FOREVER);
-	} else {
-		qspi_unlock(dev);
 	}
 }
 
@@ -273,7 +271,6 @@ static void qspi_handler(nrfx_qspi_evt_t event, void *p_context)
 
 	if (event == NRFX_QSPI_EVENT_DONE) {
 		qspi_complete(dev);
-		qspi_unlock(dev);
 	}
 }
 
@@ -319,14 +316,14 @@ static int qspi_erase(struct device *dev, u32_t addr, u32_t size)
 		return -EINVAL;
 	}
 
-	int rv = -EIO;
+	int rv = 0;
 	const struct qspi_nor_config *params = dev->config_info;
 
-	while (size) {
+	qspi_lock(dev);
+	while ((rv == 0) && (size > 0)) {
 		nrfx_err_t res = !NRFX_SUCCESS;
 		u32_t adj = 0;
 
-		qspi_lock(dev);
 		if (size == params->size) {
 			/* chip erase */
 			res = nrfx_qspi_chip_erase();
@@ -353,11 +350,13 @@ static int qspi_erase(struct device *dev, u32_t addr, u32_t size)
 			size -= adj;
 		} else {
 			LOG_ERR("erase error at 0x%lx size %zu", (long)addr, size);
-			return rv;
+			rv = qspi_get_zephyr_ret_code(res);
 		}
 	}
 
-	return 0;
+	qspi_unlock(dev);
+
+	return rv;
 }
 
 /**
@@ -529,6 +528,8 @@ static int qspi_nor_read(struct device *dev, off_t addr, void *dest,
 
 	qspi_wait_for_completion(dev, res);
 
+	qspi_unlock(dev);
+
 	int rc = qspi_get_zephyr_ret_code(res);
 
 	if ((rc == 0) && (dest != dptr)) {
@@ -621,6 +622,8 @@ static int qspi_nor_write(struct device *dev, off_t addr, const void *src,
 		qspi_wait_for_completion(dev, res);
 	}
 
+	qspi_unlock(dev);
+
 	return qspi_get_zephyr_ret_code(res);
 }