1 files changed, 51 insertions, 3 deletions

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 84c2861d6f4d..1587a4a5ff41 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -30,6 +30,7 @@
 #include <linux/slab.h>
 #include <linux/mod_devicetable.h>
 #include <linux/spi/spi.h>
+#include <linux/of_gpio.h>
 #include <linux/pm_runtime.h>
 #include <linux/export.h>
 #include <linux/sched.h>
@@ -327,6 +328,7 @@ struct spi_device *spi_alloc_device(struct spi_master *master)
         spi->dev.parent = &master->dev;
         spi->dev.bus = &spi_bus_type;
         spi->dev.release = spidev_release;
+        spi->cs_gpio = -EINVAL;
         device_initialize(&spi->dev);
         return spi;
 }
@@ -344,15 +346,16 @@ EXPORT_SYMBOL_GPL(spi_alloc_device);
 int spi_add_device(struct spi_device *spi)
 {
         static DEFINE_MUTEX(spi_add_lock);
-        struct device *dev = spi->master->dev.parent;
+        struct spi_master *master = spi->master;
+        struct device *dev = master->dev.parent;
         struct device *d;
         int status;
 
         /* Chipselects are numbered 0..max; validate. */
-        if (spi->chip_select >= spi->master->num_chipselect) {
+        if (spi->chip_select >= master->num_chipselect) {
                 dev_err(dev, "cs%d >= max %d\n",
                         spi->chip_select,
-                        spi->master->num_chipselect);
+                        master->num_chipselect);
                 return -EINVAL;
         }
 
@@ -376,6 +379,9 @@ int spi_add_device(struct spi_device *spi)
                 goto done;
         }
 
+        if (master->cs_gpios)
+                spi->cs_gpio = master->cs_gpios[spi->chip_select];
+
         /* Drivers may modify this initial i/o setup, but will
          * normally rely on the device being setup.  Devices
          * using SPI_CS_HIGH can't coexist well otherwise...
@@ -946,6 +952,44 @@ struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
 }
 EXPORT_SYMBOL_GPL(spi_alloc_master);
 
+#ifdef CONFIG_OF
+static int of_spi_register_master(struct spi_master *master)
+{
+        u16 nb;
+        int i, *cs;
+        struct device_node *np = master->dev.of_node;
+
+        if (!np)
+                return 0;
+
+        nb = of_gpio_named_count(np, "cs-gpios");
+        master->num_chipselect = max(nb, master->num_chipselect);
+
+        if (nb < 1)
+                return 0;
+
+        cs = devm_kzalloc(&master->dev,
+                          sizeof(int) * master->num_chipselect,
+                          GFP_KERNEL);
+        master->cs_gpios = cs;
+
+        if (!master->cs_gpios)
+                return -ENOMEM;
+
+        memset(cs, -EINVAL, master->num_chipselect);
+
+        for (i = 0; i < nb; i++)
+                cs[i] = of_get_named_gpio(np, "cs-gpios", i);
+
+        return 0;
+}
+#else
+static int of_spi_register_master(struct spi_master *master)
+{
+        return 0;
+}
+#endif
+
 /**
  * spi_register_master - register SPI master controller
  * @master: initialized master, originally from spi_alloc_master()
@@ -977,6 +1021,10 @@ int spi_register_master(struct spi_master *master)
         if (!dev)
                 return -ENODEV;
 
+        status = of_spi_register_master(master);
+        if (status)
+                return status;
+
         /* even if it's just one always-selected device, there must
          * be at least one chipselect
          */