fbdev/simplefb: Support memory-region property

The simple-framebuffer bindings specify that the "memory-region"
property can be used as an alternative to the "reg" property to define
the framebuffer memory used by the display hardware. Implement support
for this in the simplefb driver.

Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231101172017.3872242-2-thierry.reding@gmail.com

diff --git a/drivers/video/fbdev/simplefb.c b/drivers/video/fbdev/simplefb.c
index 62f99f6fccd3c011e26993b9e45fb17f49cb79b8..18025f34fde71e2bb6e0a3be29477e3b806ab623 100644 (file)
--- a/drivers/video/fbdev/simplefb.c
+++ b/drivers/video/fbdev/simplefb.c
@@ -21,6 +21,7 @@
 #include <linux/platform_device.h>
 #include <linux/clk.h>
 #include <linux/of.h>
+#include <linux/of_address.h>
 #include <linux/of_clk.h>
 #include <linux/of_platform.h>
 #include <linux/parser.h>
@@ -121,12 +122,13 @@ struct simplefb_params {
        u32 height;
        u32 stride;
        struct simplefb_format *format;
+       struct resource memory;
 };
 
 static int simplefb_parse_dt(struct platform_device *pdev,
                           struct simplefb_params *params)
 {
-       struct device_node *np = pdev->dev.of_node;
+       struct device_node *np = pdev->dev.of_node, *mem;
        int ret;
        const char *format;
        int i;
@@ -166,6 +168,23 @@ static int simplefb_parse_dt(struct platform_device *pdev,
                return -EINVAL;
        }
 
+       mem = of_parse_phandle(np, "memory-region", 0);
+       if (mem) {
+               ret = of_address_to_resource(mem, 0, &params->memory);
+               if (ret < 0) {
+                       dev_err(&pdev->dev, "failed to parse memory-region\n");
+                       of_node_put(mem);
+                       return ret;
+               }
+
+               if (of_property_present(np, "reg"))
+                       dev_warn(&pdev->dev, "preferring \"memory-region\" over \"reg\" property\n");
+
+               of_node_put(mem);
+       } else {
+               memset(&params->memory, 0, sizeof(params->memory));
+       }
+
        return 0;
 }
 
@@ -193,6 +212,8 @@ static int simplefb_parse_pd(struct platform_device *pdev,
                return -EINVAL;
        }
 
+       memset(&params->memory, 0, sizeof(params->memory));
+
        return 0;
 }
 
@@ -431,10 +452,14 @@ static int simplefb_probe(struct platform_device *pdev)
        if (ret)
                return ret;
 
-       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-       if (!res) {
-               dev_err(&pdev->dev, "No memory resource\n");
-               return -EINVAL;
+       if (params.memory.start == 0 && params.memory.end == 0) {
+               res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+               if (!res) {
+                       dev_err(&pdev->dev, "No memory resource\n");
+                       return -EINVAL;
+               }
+       } else {
+               res = &params.memory;
        }
 
        mem = request_mem_region(res->start, resource_size(res), "simplefb");