fbdev: ssd1307fb: Add a module parameter to set the refresh rate

This patch adds the module parameter "refreshrate" to set delay for the
deferred io. The refresh rate is given in units of Hertz. The default
refresh rate is 1 Hz. The refresh rate set through the newly introduced
parameter applies to all instances of the driver and for now it is not
possible to change it individually.

Signed-off-by: Thomas Niederprüm <niederp@physik.uni-kl.de>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

1 files changed, 17 insertions, 6 deletions

diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c
index f685d244fa2a..85eeda0fc2e4 100644
--- a/drivers/video/fbdev/ssd1307fb.c
+++ b/drivers/video/fbdev/ssd1307fb.c
@@ -38,6 +38,11 @@
 #define SSD1307FB_SET_COM_PINS_CONFIG   0xda
 #define SSD1307FB_SET_VCOMH             0xdb
 
+#define REFRESHRATE 1
+
+static u_int refreshrate = REFRESHRATE;
+module_param(refreshrate, uint, 0);
+
 struct ssd1307fb_par;
 
 struct ssd1307fb_deviceinfo {
@@ -263,11 +268,6 @@ static void ssd1307fb_deferred_io(struct fb_info *info,
         ssd1307fb_update_display(info->par);
 }
 
-static struct fb_deferred_io ssd1307fb_defio = {
-        .delay          = HZ,
-        .deferred_io    = ssd1307fb_deferred_io,
-};
-
 static int ssd1307fb_init(struct ssd1307fb_par *par)
 {
         int ret;
@@ -466,6 +466,7 @@ static int ssd1307fb_probe(struct i2c_client *client,
 {
         struct fb_info *info;
         struct device_node *node = client->dev.of_node;
+        struct fb_deferred_io *ssd1307fb_defio;
         u32 vmem_size;
         struct ssd1307fb_par *par;
         u8 *vmem;
@@ -536,10 +537,20 @@ static int ssd1307fb_probe(struct i2c_client *client,
                 goto fb_alloc_error;
         }
 
+        ssd1307fb_defio = devm_kzalloc(&client->dev, sizeof(struct fb_deferred_io), GFP_KERNEL);
+        if (!ssd1307fb_defio) {
+                dev_err(&client->dev, "Couldn't allocate deferred io.\n");
+                ret = -ENOMEM;
+                goto fb_alloc_error;
+        }
+
+        ssd1307fb_defio->delay = HZ / refreshrate;
+        ssd1307fb_defio->deferred_io = ssd1307fb_deferred_io;
+
         info->fbops = &ssd1307fb_ops;
         info->fix = ssd1307fb_fix;
         info->fix.line_length = par->width / 8;
-        info->fbdefio = &ssd1307fb_defio;
+        info->fbdefio = ssd1307fb_defio;
 
         info->var = ssd1307fb_var;
         info->var.xres = par->width;