#ifndef _SPI_H_
#define _SPI_H_
+/* Controller-specific definitions: */
+
+/* CONFIG_HARD_SPI triggers SPI bus initialization in PowerPC */
+#ifdef CONFIG_MPC8XXX_SPI
+# ifndef CONFIG_HARD_SPI
+# define CONFIG_HARD_SPI
+# endif
+#endif
+
/* SPI mode flags */
#define SPI_CPHA 0x01 /* clock phase */
#define SPI_CPOL 0x02 /* clock polarity */
#define SPI_MODE_1 (0|SPI_CPHA)
#define SPI_MODE_2 (SPI_CPOL|0)
#define SPI_MODE_3 (SPI_CPOL|SPI_CPHA)
-#define SPI_CS_HIGH 0x04 /* chipselect active high? */
+#define SPI_CS_HIGH 0x04 /* CS active high */
#define SPI_LSB_FIRST 0x08 /* per-word bits-on-wire */
#define SPI_3WIRE 0x10 /* SI/SO signals shared */
#define SPI_LOOP 0x20 /* loopback mode */
-/*
- * The function call pointer type used to drive the chip select.
- */
-typedef void (*spi_chipsel_type)(int cs);
+/* SPI transfer flags */
+#define SPI_XFER_BEGIN 0x01 /* Assert CS before transfer */
+#define SPI_XFER_END 0x02 /* Deassert CS after transfer */
+/*-----------------------------------------------------------------------
+ * Representation of a SPI slave, i.e. what we're communicating with.
+ *
+ * Drivers are expected to extend this with controller-specific data.
+ *
+ * bus: ID of the bus that the slave is attached to.
+ * cs: ID of the chip select connected to the slave.
+ */
+struct spi_slave {
+ unsigned int bus;
+ unsigned int cs;
+};
/*-----------------------------------------------------------------------
* Initialization, must be called once on start up.
+ *
+ * TODO: I don't think we really need this.
*/
void spi_init(void);
+/*-----------------------------------------------------------------------
+ * Set up communications parameters for a SPI slave.
+ *
+ * This must be called once for each slave. Note that this function
+ * usually doesn't touch any actual hardware, it only initializes the
+ * contents of spi_slave so that the hardware can be easily
+ * initialized later.
+ *
+ * bus: Bus ID of the slave chip.
+ * cs: Chip select ID of the slave chip on the specified bus.
+ * max_hz: Maximum SCK rate in Hz.
+ * mode: Clock polarity, clock phase and other parameters.
+ *
+ * Returns: A spi_slave reference that can be used in subsequent SPI
+ * calls, or NULL if one or more of the parameters are not supported.
+ */
+struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
+ unsigned int max_hz, unsigned int mode);
+
+/*-----------------------------------------------------------------------
+ * Free any memory associated with a SPI slave.
+ *
+ * slave: The SPI slave
+ */
+void spi_free_slave(struct spi_slave *slave);
+
+/*-----------------------------------------------------------------------
+ * Claim the bus and prepare it for communication with a given slave.
+ *
+ * This must be called before doing any transfers with a SPI slave. It
+ * will enable and initialize any SPI hardware as necessary, and make
+ * sure that the SCK line is in the correct idle state. It is not
+ * allowed to claim the same bus for several slaves without releasing
+ * the bus in between.
+ *
+ * slave: The SPI slave
+ *
+ * Returns: 0 if the bus was claimed successfully, or a negative value
+ * if it wasn't.
+ */
+int spi_claim_bus(struct spi_slave *slave);
+
+/*-----------------------------------------------------------------------
+ * Release the SPI bus
+ *
+ * This must be called once for every call to spi_claim_bus() after
+ * all transfers have finished. It may disable any SPI hardware as
+ * appropriate.
+ *
+ * slave: The SPI slave
+ */
+void spi_release_bus(struct spi_slave *slave);
/*-----------------------------------------------------------------------
* SPI transfer
* input data overwrites the output data (since both are buffered by
* temporary variables, this is OK).
*
- * If the chipsel() function is not NULL, it is called with a parameter
- * of '1' (chip select active) at the start of the transfer and again with
- * a parameter of '0' at the end of the transfer.
- *
- * If the chipsel() function _is_ NULL, it the responsibility of the
- * caller to make the appropriate chip select active before calling
- * spi_xfer() and making it inactive after spi_xfer() returns.
- *
* spi_xfer() interface:
- * chipsel: Routine to call to set/clear the chip select:
- * if chipsel is NULL, it is not used.
- * if(cs), make the chip select active (typically '0').
- * if(!cs), make the chip select inactive (typically '1').
- * dout: Pointer to a string of bits to send out. The bits are
- * held in a byte array and are sent MSB first.
- * din: Pointer to a string of bits that will be filled in.
- * bitlen: How many bits to write and read.
+ * slave: The SPI slave which will be sending/receiving the data.
+ * bitlen: How many bits to write and read.
+ * dout: Pointer to a string of bits to send out. The bits are
+ * held in a byte array and are sent MSB first.
+ * din: Pointer to a string of bits that will be filled in.
+ * flags: A bitwise combination of SPI_XFER_* flags.
*
* Returns: 0 on success, not 0 on failure
*/
-int spi_xfer(spi_chipsel_type chipsel, int bitlen, uchar *dout, uchar *din);
+int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
+ void *din, unsigned long flags);
+
+/*-----------------------------------------------------------------------
+ * Determine if a SPI chipselect is valid.
+ * This function is provided by the board if the low-level SPI driver
+ * needs it to determine if a given chipselect is actually valid.
+ *
+ * Returns: 1 if bus:cs identifies a valid chip on this board, 0
+ * otherwise.
+ */
+int spi_cs_is_valid(unsigned int bus, unsigned int cs);
+
+/*-----------------------------------------------------------------------
+ * Activate a SPI chipselect.
+ * This function is provided by the board code when using a driver
+ * that can't control its chipselects automatically (e.g.
+ * common/soft_spi.c). When called, it should activate the chip select
+ * to the device identified by "slave".
+ */
+void spi_cs_activate(struct spi_slave *slave);
+
+/*-----------------------------------------------------------------------
+ * Deactivate a SPI chipselect.
+ * This function is provided by the board code when using a driver
+ * that can't control its chipselects automatically (e.g.
+ * common/soft_spi.c). When called, it should deactivate the chip
+ * select to the device identified by "slave".
+ */
+void spi_cs_deactivate(struct spi_slave *slave);
+
+/*-----------------------------------------------------------------------
+ * Write 8 bits, then read 8 bits.
+ * slave: The SPI slave we're communicating with
+ * byte: Byte to be written
+ *
+ * Returns: The value that was read, or a negative value on error.
+ *
+ * TODO: This function probably shouldn't be inlined.
+ */
+static inline int spi_w8r8(struct spi_slave *slave, unsigned char byte)
+{
+ unsigned char dout[2];
+ unsigned char din[2];
+ int ret;
+
+ dout[0] = byte;
+ dout[1] = 0;
-int spi_select(unsigned int bus, unsigned int dev, unsigned long mode);
+ ret = spi_xfer(slave, 16, dout, din, SPI_XFER_BEGIN | SPI_XFER_END);
+ return ret < 0 ? ret : din[1];
+}
#endif /* _SPI_H_ */
projects / karo-tx-uboot.git / blobdiff