simple-framebuffer enquire

From: Michael Nazzareno Trimarchi
Date: Mon Jun 25 2018 - 09:29:35 EST


Hi Hans

In order to let it even registered the simplefb I have added this
change. According on what I understand
from the code seems that this is the way to acquire memory with the
correct attribute

diff --git a/drivers/video/fbdev/simplefb.c b/drivers/video/fbdev/simplefb.c
index a3c44ec..7e61ce3 100644
--- a/drivers/video/fbdev/simplefb.c
+++ b/drivers/video/fbdev/simplefb.c
@@ -466,8 +466,8 @@ static int simplefb_probe(struct platform_device *pdev)

info->fbops = &simplefb_ops;
info->flags = FBINFO_DEFAULT | FBINFO_MISC_FIRMWARE;
- info->screen_base = ioremap_wc(info->fix.smem_start,
- info->fix.smem_len);
+ info->screen_base = arch_memremap_wb(info->fix.smem_start,
+ info->fix.smem_len);
if (!info->screen_base) {
ret = -ENOMEM;
goto error_fb_release;

Another question is

aliases {
display0 = &lcdif;
};

chosen {
#address-cells = <1>;
#size-cells = <1>;
ranges;

stdout-path = &uart1;
framebuffer0: framebuffer@86fd6080 {
compatible = "simple-framebuffer";
reg = <0x86fd6080 (480 * 272 * 4)>;
width = <480>;
height = <272>;
stride = <(480 * 4)>;
format = "a8r8g8b8";
clocks = <&clks IMX6UL_CLK_LCDIF_PIX>,
<&clks IMX6UL_CLK_LCDIF_APB>,
<&clks IMX6UL_CLK_DUMMY>,
<&clks IMX6UL_CLK_GPIO3>,
<&clks IMX6UL_CLK_GPIO4>;
nshut-supply = <&reg_lcd_nshut>;
nreset-supply = <&reg_lcd_nreset>;
display = <&lcdif>;
};
};
};

How do you ensure that regulators that are bind to gpios can be
maintain during boot?
A small minor comment is how to automatic switch then to normal
framebuffer. Anyway seems
that
#address-cells = <1>;
#size-cells = <1>;
ranges;

are mandatory and they are in the dts documentation.

Best regards
Michael