spi: xilinx_spi: Perform software reset during slave setup

to make sure it is in the clear state.

Signed-off-by: Jason Wu <huanyu@xilinx.com>

drivers/spi/xilinx_spi.c

@@ -99,6 +99,8 @@ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
 	debug("%s: bus:%i cs:%i base:%p mode:%x max_hz:%d\n", __func__,
 		bus, cs, xilspi->regs, xilspi->mode, xilspi->freq);
 
+	writel(SPISSR_RESET_VALUE, &xilspi->regs->srr);
+
 	return &xilspi->slave;
 }
 

drivers/spi/xilinx_spi.h

@@ -119,6 +119,9 @@ struct xilinx_spi_reg {
 #define SPIRFOR_OCYVAL_POS	0
 #define SPIRFOR_OCYVAL_MASK	(0xf << SPIRFOR_OCYVAL_POS)
 
+/* SPI Software Reset Register (ssr) */
+#define SPISSR_RESET_VALUE	0x0a
+
 struct xilinx_spi_slave {
 	struct spi_slave slave;
 	struct xilinx_spi_reg *regs;