dm: spi: Move slave details to child platdata

At present we go through various contortions to store the SPI slave's chip
select in its private data. This only exists when the slave is active so
must be set up when it is probed. Until the device is probed we don't
actually know what chip select it will appear on.

However, now that we can support per-child platform data, we can use that
instead. This allows us to set up the chip select when the child is bound,
and avoid the messy contortions.

Unfortunately this is a fairly large change and it seems to be difficult to
break it down further.

Signed-off-by: Simon Glass <sjg@chromium.org>

1 files changed, 32 insertions, 10 deletions

diff --git a/include/spi.h b/include/spi.h
index ec17bd0..c58e453 100644
--- a/include/spi.h
+++ b/include/spi.h
@@ -56,20 +56,42 @@
 #define SPI_DEFAULT_WORDLEN 8
 
 #ifdef CONFIG_DM_SPI
+/* TODO(sjg@chromium.org): Remove this and use max_hz from struct spi_slave */
 struct dm_spi_bus {
 	uint max_hz;
 };
 
+/**
+ * struct dm_spi_platdata - platform data for all SPI slaves
+ *
+ * This describes a SPI slave, a child device of the SPI bus. To obtain this
+ * struct from a spi_slave, use dev_get_parent_platdata(dev) or
+ * dev_get_parent_platdata(slave->dev).
+ *
+ * This data is immuatable. Each time the device is probed, @max_hz and @mode
+ * will be copied to struct spi_slave.
+ *
+ * @cs:		Chip select number (0..n-1)
+ * @max_hz:	Maximum bus speed that this slave can tolerate
+ * @mode:	SPI mode to use for this device (see SPI mode flags)
+ */
+struct dm_spi_slave_platdata {
+	unsigned int cs;
+	uint max_hz;
+	uint mode;
+};
+
 #endif /* CONFIG_DM_SPI */
 
 /**
  * struct spi_slave - Representation of a SPI slave
  *
  * For driver model this is the per-child data used by the SPI bus. It can
- * be accessed using dev_get_parentdata() on the slave device. Each SPI
- * driver should define this child data in its U_BOOT_DRIVER() definition:
- *
- *	.per_child_auto_alloc_size	= sizeof(struct spi_slave),
+ * be accessed using dev_get_parentdata() on the slave device. The SPI uclass
+ * sets uip per_child_auto_alloc_size to sizeof(struct spi_slave), and the
+ * driver should not override it. Two platform data fields (max_hz and mode)
+ * are copied into this structure to provide an initial value. This allows
+ * them to be changed, since we should never change platform data in drivers.
  *
  * If not using driver model, drivers are expected to extend this with
  * controller-specific data.
@@ -97,8 +119,8 @@ struct spi_slave {
 	uint mode;
 #else
 	unsigned int bus;
-#endif
 	unsigned int cs;
+#endif
 	u8 op_mode_rx;
 	u8 op_mode_tx;
 	unsigned int wordlen;
@@ -545,16 +567,16 @@ int spi_chip_select(struct udevice *slave);
 int spi_find_chip_select(struct udevice *bus, int cs, struct udevice **devp);
 
 /**
- * spi_ofdata_to_platdata() - decode standard SPI platform data
+ * spi_slave_ofdata_to_platdata() - decode standard SPI platform data
  *
- * This decodes the speed and mode from a device tree node and puts it into
- * the spi_slave structure.
+ * This decodes the speed and mode for a slave from a device tree node
  *
  * @blob:	Device tree blob
  * @node:	Node offset to read from
- * @spi:	Place to put the decoded information
+ * @plat:	Place to put the decoded information
  */
-int spi_ofdata_to_platdata(const void *blob, int node, struct spi_slave *spi);
+int spi_slave_ofdata_to_platdata(const void *blob, int node,
+				 struct dm_spi_slave_platdata *plat);
 
 /**
  * spi_cs_info() - Check information on a chip select