mfd: clsic: Add support for smaller SPI transfers

Change-Id: I090245544b85d440dc8b8db5cbcd4335c74b5408
Signed-off-by: Lucas Tanure <[email protected]>

Author: Lucas Tanure

Documentation/devicetree/bindings/mfd/clsic.txt

@@ -67,6 +67,10 @@ Optional properties:
     set to a default of 32, this property allows that value to be adjusted to
     support different CLSIC devices that may require a pad_bits of 16.
 
+  - spi-max-pages : Maximum number of pages (PAGE_SIZE) that can be transferred
+    at once by spi bus. Without this property the driver will set the maximum
+    size to be (32 X 1024) bytes.
+
   - MICBIAS1x : Initial data for the MICBIAS regulators, as covered in
     Documentation/devicetree/bindings/regulator/regulator.txt.
 

drivers/mfd/clsic/clsic-core.c

@@ -378,7 +378,7 @@ static void clsic_boot(struct clsic *clsic)
 
 int clsic_dev_init(struct clsic *clsic)
 {
-	int ret = 0;
+	int ret = 0, max_pg = 0;
 
 	trace_clsic_dev_init(clsic_bootonload);
 
@@ -408,6 +408,13 @@ int clsic_dev_init(struct clsic *clsic)
 
 	clsic->volatile_memory = of_property_read_bool(clsic->dev->of_node,
 						       "volatile_memory");
+	ret = of_property_read_u32(clsic->dev->of_node, "spi-max-pages",
+				   &max_pg);
+	if (ret == 0 && max_pg > 0)
+		clsic->spi_max_transfer = min_t(size_t, max_pg * PAGE_SIZE,
+						CLSIC_FIFO_TRANSACTION_MAX);
+	else
+		clsic->spi_max_transfer = CLSIC_FIFO_TRANSACTION_MAX;
 
 	INIT_DELAYED_WORK(&clsic->maintenance_handler, clsic_maintenance);
 

drivers/mfd/clsic/clsic-msg.c

@@ -1060,7 +1060,7 @@ static int clsic_fifo_read(struct clsic *clsic, uint8_t *dest,
 
 	while (bytes_left != 0) {
 		bytes_thisread = min_t(uint32_t, bytes_left,
-				       CLSIC_FIFO_TRANSACTION_MAX);
+				       clsic->spi_max_transfer);
 		ret = regmap_raw_read(clsic->regmap, clsic->fifo_tx,
 				      tmp_dest, bytes_thisread);
 		if (ret != 0)
@@ -1088,7 +1088,7 @@ static int clsic_fifo_write(struct clsic *clsic, uint8_t *src,
 
 	while (bytes_left != 0) {
 		bytes_thiswrite = min_t(uint32_t, bytes_left,
-					CLSIC_FIFO_TRANSACTION_MAX);
+					clsic->spi_max_transfer);
 		ret = regmap_raw_write(clsic->regmap,
 				       TACNA_CPF1_RX_WRDATA,
 				       tmp_src, bytes_thiswrite);

include/linux/mfd/clsic/core.h

@@ -178,6 +178,7 @@ struct clsic {
 	 * downloaded on every reset or power on.
 	 */
 	bool volatile_memory;
+	size_t spi_max_transfer;
 
 	int irq;