atmel_spi: Driver for the Atmel SPI controller

This adds a driver for the SPI controller found on most AT91 and AVR32
chips, implementing the new SPI API.

Changed in v4:
  - Update to new API
  - Handle zero-length transfers appropriately. The user may send a
    zero-length SPI transfer with SPI_XFER_END set in order to
    deactivate the chip select after a series of transfers with chip
    select active. This is useful e.g. when polling the status
    register of DataFlash.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>

1 files changed, 95 insertions, 0 deletions

diff --git a/drivers/spi/atmel_spi.h b/drivers/spi/atmel_spi.h
new file mode 100644
index 0000000..8b69a6d
--- /dev/null
+++ b/drivers/spi/atmel_spi.h
@@ -0,0 +1,95 @@
+/*
+ * Register definitions for the Atmel AT32/AT91 SPI Controller
+ */
+
+/* Register offsets */
+#define ATMEL_SPI_CR			0x0000
+#define ATMEL_SPI_MR			0x0004
+#define ATMEL_SPI_RDR			0x0008
+#define ATMEL_SPI_TDR			0x000c
+#define ATMEL_SPI_SR			0x0010
+#define ATMEL_SPI_IER			0x0014
+#define ATMEL_SPI_IDR			0x0018
+#define ATMEL_SPI_IMR			0x001c
+#define ATMEL_SPI_CSR(x)		(0x0030 + 4 * (x))
+#define ATMEL_SPI_VERSION		0x00fc
+
+/* Bits in CR */
+#define ATMEL_SPI_CR_SPIEN		(1 << 0)
+#define ATMEL_SPI_CR_SPIDIS		(1 << 1)
+#define ATMEL_SPI_CR_SWRST		(1 << 7)
+#define ATMEL_SPI_CR_LASTXFER		(1 << 24)
+
+/* Bits in MR */
+#define ATMEL_SPI_MR_MSTR		(1 << 0)
+#define ATMEL_SPI_MR_PS			(1 << 1)
+#define ATMEL_SPI_MR_PCSDEC		(1 << 2)
+#define ATMEL_SPI_MR_FDIV		(1 << 3)
+#define ATMEL_SPI_MR_MODFDIS		(1 << 4)
+#define ATMEL_SPI_MR_LLB		(1 << 7)
+#define ATMEL_SPI_MR_PCS(x)		(((x) & 15) << 16)
+#define ATMEL_SPI_MR_DLYBCS(x)		((x) << 24)
+
+/* Bits in RDR */
+#define ATMEL_SPI_RDR_RD(x)		(x)
+#define ATMEL_SPI_RDR_PCS(x)		((x) << 16)
+
+/* Bits in TDR */
+#define ATMEL_SPI_TDR_TD(x)		(x)
+#define ATMEL_SPI_TDR_PCS(x)		((x) << 16)
+#define ATMEL_SPI_TDR_LASTXFER		(1 << 24)
+
+/* Bits in SR/IER/IDR/IMR */
+#define ATMEL_SPI_SR_RDRF		(1 << 0)
+#define ATMEL_SPI_SR_TDRE		(1 << 1)
+#define ATMEL_SPI_SR_MODF		(1 << 2)
+#define ATMEL_SPI_SR_OVRES		(1 << 3)
+#define ATMEL_SPI_SR_ENDRX		(1 << 4)
+#define ATMEL_SPI_SR_ENDTX		(1 << 5)
+#define ATMEL_SPI_SR_RXBUFF		(1 << 6)
+#define ATMEL_SPI_SR_TXBUFE		(1 << 7)
+#define ATMEL_SPI_SR_NSSR		(1 << 8)
+#define ATMEL_SPI_SR_TXEMPTY		(1 << 9)
+#define ATMEL_SPI_SR_SPIENS		(1 << 16)
+
+/* Bits in CSRx */
+#define ATMEL_SPI_CSRx_CPOL		(1 << 0)
+#define ATMEL_SPI_CSRx_NCPHA		(1 << 1)
+#define ATMEL_SPI_CSRx_CSAAT		(1 << 3)
+#define ATMEL_SPI_CSRx_BITS(x)		((x) << 4)
+#define ATMEL_SPI_CSRx_SCBR(x)		((x) << 8)
+#define ATMEL_SPI_CSRx_SCBR_MAX		0xff
+#define ATMEL_SPI_CSRx_DLYBS(x)		((x) << 16)
+#define ATMEL_SPI_CSRx_DLYBCT(x)	((x) << 24)
+
+/* Bits in VERSION */
+#define ATMEL_SPI_VERSION_REV(x)	((x) << 0)
+#define ATMEL_SPI_VERSION_MFN(x)	((x) << 16)
+
+/* Constants for CSRx:BITS */
+#define ATMEL_SPI_BITS_8		0
+#define ATMEL_SPI_BITS_9		1
+#define ATMEL_SPI_BITS_10		2
+#define ATMEL_SPI_BITS_11		3
+#define ATMEL_SPI_BITS_12		4
+#define ATMEL_SPI_BITS_13		5
+#define ATMEL_SPI_BITS_14		6
+#define ATMEL_SPI_BITS_15		7
+#define ATMEL_SPI_BITS_16		8
+
+struct atmel_spi_slave {
+	struct spi_slave slave;
+	void		*regs;
+	u32		mr;
+};
+
+static inline struct atmel_spi_slave *to_atmel_spi(struct spi_slave *slave)
+{
+	return container_of(slave, struct atmel_spi_slave, slave);
+}
+
+/* Register access macros */
+#define spi_readl(as, reg)					\
+	readl(as->regs + ATMEL_SPI_##reg)
+#define spi_writel(as, reg, value)				\
+	writel(value, as->regs + ATMEL_SPI_##reg)