spi: altera: add platform data for slave information.

This patch introduces platform data for slave information, it allows
spi-altera to add new spi devices once master registration is done.
Signed-off-by: Wu Hao <hao.wu@intel.com>
Signed-off-by: Xu Yilun <yilun.xu@intel.com>
Signed-off-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
Signed-off-by: Russ Weight <russell.h.weight@intel.com>
Reviewed-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/1591845911-10197-4-git-send-email-yilun.xu@intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-altera.c

@@ -189,6 +189,7 @@ static int altera_spi_probe(struct platform_device *pdev)
 	struct altera_spi *hw;
 	struct spi_master *master;
 	int err = -ENODEV;
+	u16 i;
 
 	master = spi_alloc_master(&pdev->dev, sizeof(struct altera_spi));
 	if (!master)
@@ -244,6 +245,16 @@ static int altera_spi_probe(struct platform_device *pdev)
 	err = devm_spi_register_master(&pdev->dev, master);
 	if (err)
 		goto exit;
+
+	if (pdata) {
+		for (i = 0; i < pdata->num_devices; i++) {
+			if (!spi_new_device(master, pdata->devices + i))
+				dev_warn(&pdev->dev,
+					 "unable to create SPI device: %s\n",
+					 pdata->devices[i].modalias);
+		}
+	}
+
 	dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq);
 
 	return 0;

include/linux/spi/altera.h

@@ -14,11 +14,16 @@
  * @mode_bits:		Mode bits of SPI master.
  * @num_chipselect:	Number of chipselects.
  * @bits_per_word_mask:	bitmask of supported bits_per_word for transfers.
+ * @num_devices:	Number of devices that shall be added when the driver
+ *			is probed.
+ * @devices:		The devices to add.
  */
 struct altera_spi_platform_data {
 	u16				mode_bits;
 	u16				num_chipselect;
 	u32				bits_per_word_mask;
+	u16				num_devices;
+	struct spi_board_info		*devices;
 };
 
 #endif /* __LINUX_SPI_ALTERA_H */