1 files changed, 29 insertions, 13 deletions

diff --git a/chip/g/spi_controller.c b/chip/g/spi_controller.c
index 912520e52f..4f7a5ee512 100644
--- a/chip/g/spi_controller.c
+++ b/chip/g/spi_controller.c
@@ -33,10 +33,12 @@ static enum spi_clock_mode clock_mode[SPI_NUM_PORTS];
  * The Cr50 SPI controller is not DMA auto-fill/drain capable, so async and
  * flush are not defined on purpose.
  */
-int spi_transaction(const struct spi_device_t *spi_device,
-		    const uint8_t *txdata, int txlen,
-		    uint8_t *rxdata, int rxlen)
+int spi_sub_transaction(const struct spi_device_t *spi_device,
+			const uint8_t *txdata, int txlen, uint8_t *rxdata,
+			int rxlen, bool deassert_cs)
 {
+	static bool cs_asserted;
+
 	int port = spi_device->port;
 	int rv = EC_SUCCESS;
 	timestamp_t timeout;
@@ -74,8 +76,9 @@ int spi_transaction(const struct spi_device_t *spi_device,
 		rxoffset = txlen;
 	}
 
-	/* Grab the port's mutex. */
-	mutex_lock(&spi_mutex[port]);
+	if (!cs_asserted)
+		/* Grab the port's mutex. */
+		mutex_lock(&spi_mutex[port]);
 
 #ifdef CONFIG_STREAM_SIGNATURE
 	/*
@@ -88,10 +91,13 @@ int spi_transaction(const struct spi_device_t *spi_device,
 	/* Copy the txdata into the 128B Transmit Buffer. */
 	memmove((uint8_t *)GREG32_ADDR_I(SPI, port, TX_DATA), txdata, txlen);
 
+	if (!cs_asserted) {
 #ifndef CONFIG_SPI_CONTROLLER_NO_CS_GPIOS
-	/* Drive chip select low. */
-	gpio_set_level(spi_device->gpio_cs, 0);
-#endif  /* CONFIG_SPI_CONTROLLER_NO_CS_GPIOS */
+		/* Drive chip select low. */
+		gpio_set_level(spi_device->gpio_cs, 0);
+#endif
+		cs_asserted = true;
+	}
 
 	/* Initiate the transaction. */
 	GWRITE_FIELD_I(SPI, port, ISTATE_CLR, TXDONE, 1);
@@ -120,16 +126,26 @@ int spi_transaction(const struct spi_device_t *spi_device,
 		rxlen);
 
 err_cs_high:
+	if ((rv != EC_SUCCESS) || deassert_cs) {
 #ifndef CONFIG_SPI_CONTROLLER_NO_CS_GPIOS
-	/* Drive chip select high. */
-	gpio_set_level(spi_device->gpio_cs, 1);
+		/* Drive chip select high. */
+		gpio_set_level(spi_device->gpio_cs, 1);
 #endif  /* CONFIG_SPI_CONTROLLER_NO_CS_GPIOS */
-
-	/* Release the port's mutex. */
-	mutex_unlock(&spi_mutex[port]);
+		cs_asserted = false;
+		/* Release the port's mutex. */
+		mutex_unlock(&spi_mutex[port]);
+	}
 	return rv;
 }
 
+int spi_transaction(const struct spi_device_t *spi_device,
+		    const uint8_t *txdata, int txlen, uint8_t *rxdata,
+		    int rxlen)
+{
+	return spi_sub_transaction(spi_device, txdata, txlen, rxdata, rxlen,
+				   true);
+}
+
 /*
  * Configure the SPI port's clock mode. The SPI port must be re-enabled after
  * changing the clocking mode.