[PATCHv2 07/10] fbdev: ssd1307fb: Add module parameter to set refresh rate of the display

["Thomas Niederprüm" <niederp@physik.uni-kl.de>]

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.

Signed-off-by: Thomas Niederprüm <niederp@physik.uni-kl.de>
---
 drivers/video/fbdev/ssd1307fb.c | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c
index c7ed287..ea58e87 100644
--- a/drivers/video/fbdev/ssd1307fb.c
+++ b/drivers/video/fbdev/ssd1307fb.c
@@ -43,6 +43,11 @@
 #define	SSD1307FB_SET_COM_PINS_CONFIG	0xda
 #define	SSD1307FB_SET_VCOMH		0xdb
 
+#define REFRASHRATE 1
+
+static u_int refreshrate = REFRASHRATE;
+module_param(refreshrate, uint, 0);
+
 static u_int contrast = 128;
 module_param(contrast, uint, S_IRUGO);
 
@@ -270,11 +275,6 @@ 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;
@@ -475,6 +475,7 @@ 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;
@@ -544,10 +545,20 @@ 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;
-- 
2.3.0