drivers: spi_context: Functions for remaining len

Add functions to get remaining length in the transfer. Refactor a bit to
avoid duplicate code for the for loop that is the same as in the total
length function.

The difference between the total length and left length function is that
the current buffer total length is counted in the former and the current
buffer remaining length is counted in the latter.

Signed-off-by: Declan Snyder <[email protected]>

Author: decsny

drivers/spi/spi_context.h

@@ -437,30 +437,51 @@ static inline size_t spi_context_longest_current_buf(struct spi_context *ctx)
 	return ctx->tx_len > ctx->rx_len ? ctx->tx_len : ctx->rx_len;
 }
 
-static inline size_t spi_context_total_tx_len(struct spi_context *ctx)
+static size_t spi_context_count_tx_buf_lens(struct spi_context *ctx, size_t start_index)
 {
 	size_t n;
 	size_t total_len = 0;
 
-	for (n = 0; n < ctx->tx_count; ++n) {
+	for (n = start_index; n < ctx->tx_count; ++n) {
 		total_len += ctx->current_tx[n].len;
 	}
 
 	return total_len;
 }
 
-static inline size_t spi_context_total_rx_len(struct spi_context *ctx)
+static size_t spi_context_count_rx_buf_lens(struct spi_context *ctx, size_t start_index)
 {
 	size_t n;
 	size_t total_len = 0;
 
-	for (n = 0; n < ctx->rx_count; ++n) {
+	for (n = start_index; n < ctx->rx_count; ++n) {
 		total_len += ctx->current_rx[n].len;
 	}
 
 	return total_len;
 }
 
+
+static inline size_t spi_context_total_tx_len(struct spi_context *ctx)
+{
+	return spi_context_count_tx_buf_lens(ctx, 0);
+}
+
+static inline size_t spi_context_total_rx_len(struct spi_context *ctx)
+{
+	return spi_context_count_rx_buf_lens(ctx, 0);
+}
+
+static inline size_t spi_context_tx_len_left(struct spi_context *ctx)
+{
+	return ctx->tx_len + spi_context_count_tx_buf_lens(ctx, 1);
+}
+
+static inline size_t spi_context_rx_len_left(struct spi_context *ctx)
+{
+	return ctx->rx_len + spi_context_count_rx_buf_lens(ctx, 1);
+}
+
 #ifdef __cplusplus
 }
 #endif