1 ================================ 1 ================================
2 Driver for EP93xx LCD controller 2 Driver for EP93xx LCD controller
3 ================================ 3 ================================
4 4
5 The EP93xx LCD controller can drive both stand 5 The EP93xx LCD controller can drive both standard desktop monitors and
6 embedded LCD displays. If you have a standard 6 embedded LCD displays. If you have a standard desktop monitor then you
7 can use the standard Linux video mode database 7 can use the standard Linux video mode database. In your board file::
8 8
9 static struct ep93xxfb_mach_info some_ 9 static struct ep93xxfb_mach_info some_board_fb_info = {
10 .num_modes = EP93XXFB_USE 10 .num_modes = EP93XXFB_USE_MODEDB,
11 .bpp = 16, 11 .bpp = 16,
12 }; 12 };
13 13
14 If you have an embedded LCD display then you n 14 If you have an embedded LCD display then you need to define a video
15 mode for it as follows:: 15 mode for it as follows::
16 16
17 static struct fb_videomode some_board_ 17 static struct fb_videomode some_board_video_modes[] = {
18 { 18 {
19 .name = "som 19 .name = "some_lcd_name",
20 /* Pixel clock, porche 20 /* Pixel clock, porches, etc */
21 }, 21 },
22 }; 22 };
23 23
24 Note that the pixel clock value is in pico-sec 24 Note that the pixel clock value is in pico-seconds. You can use the
25 KHZ2PICOS macro to convert the pixel clock val 25 KHZ2PICOS macro to convert the pixel clock value. Most other values
26 are in pixel clocks. See Documentation/fb/fram 26 are in pixel clocks. See Documentation/fb/framebuffer.rst for further
27 details. 27 details.
28 28
29 The ep93xxfb_mach_info structure for your boar 29 The ep93xxfb_mach_info structure for your board should look like the
30 following:: 30 following::
31 31
32 static struct ep93xxfb_mach_info some_ 32 static struct ep93xxfb_mach_info some_board_fb_info = {
33 .num_modes = ARRAY_SIZE(s 33 .num_modes = ARRAY_SIZE(some_board_video_modes),
34 .modes = some_board_v 34 .modes = some_board_video_modes,
35 .default_mode = &some_board_ 35 .default_mode = &some_board_video_modes[0],
36 .bpp = 16, 36 .bpp = 16,
37 }; 37 };
38 38
39 The framebuffer device can be registered by ad 39 The framebuffer device can be registered by adding the following to
40 your board initialisation function:: 40 your board initialisation function::
41 41
42 ep93xx_register_fb(&some_board_fb_info 42 ep93xx_register_fb(&some_board_fb_info);
43 43
44 ===================== 44 =====================
45 Video Attribute Flags 45 Video Attribute Flags
46 ===================== 46 =====================
47 47
48 The ep93xxfb_mach_info structure has a flags f 48 The ep93xxfb_mach_info structure has a flags field which can be used
49 to configure the controller. The video attribu 49 to configure the controller. The video attributes flags are fully
50 documented in section 7 of the EP93xx users' g 50 documented in section 7 of the EP93xx users' guide. The following
51 flags are available: 51 flags are available:
52 52
53 =============================== ============== 53 =============================== ==========================================
54 EP93XXFB_PCLK_FALLING Clock data on 54 EP93XXFB_PCLK_FALLING Clock data on the falling edge of the
55 pixel clock. T 55 pixel clock. The default is to clock
56 data on the ri 56 data on the rising edge.
57 57
58 EP93XXFB_SYNC_BLANK_HIGH Blank signal i 58 EP93XXFB_SYNC_BLANK_HIGH Blank signal is active high. By
59 default the bl 59 default the blank signal is active low.
60 60
61 EP93XXFB_SYNC_HORIZ_HIGH Horizontal syn 61 EP93XXFB_SYNC_HORIZ_HIGH Horizontal sync is active high. By
62 default the ho 62 default the horizontal sync is active low.
63 63
64 EP93XXFB_SYNC_VERT_HIGH Vertical sync 64 EP93XXFB_SYNC_VERT_HIGH Vertical sync is active high. By
65 default the ve 65 default the vertical sync is active high.
66 =============================== ============== 66 =============================== ==========================================
67 67
68 The physical address of the framebuffer can be 68 The physical address of the framebuffer can be controlled using the
69 following flags: 69 following flags:
70 70
71 =============================== ============== 71 =============================== ======================================
72 EP93XXFB_USE_SDCSN0 Use SDCSn[0] f 72 EP93XXFB_USE_SDCSN0 Use SDCSn[0] for the framebuffer. This
73 is the default 73 is the default setting.
74 74
75 EP93XXFB_USE_SDCSN1 Use SDCSn[1] f 75 EP93XXFB_USE_SDCSN1 Use SDCSn[1] for the framebuffer.
76 76
77 EP93XXFB_USE_SDCSN2 Use SDCSn[2] f 77 EP93XXFB_USE_SDCSN2 Use SDCSn[2] for the framebuffer.
78 78
79 EP93XXFB_USE_SDCSN3 Use SDCSn[3] f 79 EP93XXFB_USE_SDCSN3 Use SDCSn[3] for the framebuffer.
80 =============================== ============== 80 =============================== ======================================
81 81
82 ================== 82 ==================
83 Platform callbacks 83 Platform callbacks
84 ================== 84 ==================
85 85
86 The EP93xx framebuffer driver supports three o 86 The EP93xx framebuffer driver supports three optional platform
87 callbacks: setup, teardown and blank. The setu 87 callbacks: setup, teardown and blank. The setup and teardown functions
88 are called when the framebuffer driver is inst 88 are called when the framebuffer driver is installed and removed
89 respectively. The blank function is called whe 89 respectively. The blank function is called whenever the display is
90 blanked or unblanked. 90 blanked or unblanked.
91 91
92 The setup and teardown devices pass the platfo 92 The setup and teardown devices pass the platform_device structure as
93 an argument. The fb_info and ep93xxfb_mach_inf 93 an argument. The fb_info and ep93xxfb_mach_info structures can be
94 obtained as follows:: 94 obtained as follows::
95 95
96 static int some_board_fb_setup(struct 96 static int some_board_fb_setup(struct platform_device *pdev)
97 { 97 {
98 struct ep93xxfb_mach_info *mac 98 struct ep93xxfb_mach_info *mach_info = pdev->dev.platform_data;
99 struct fb_info *fb_info = plat 99 struct fb_info *fb_info = platform_get_drvdata(pdev);
100 100
101 /* Board specific framebuffer 101 /* Board specific framebuffer setup */
102 } 102 }
103 103
104 ====================== 104 ======================
105 Setting the video mode 105 Setting the video mode
106 ====================== 106 ======================
107 107
108 The video mode is set using the following synt 108 The video mode is set using the following syntax::
109 109
110 video=XRESxYRES[-BPP][@REFRESH] 110 video=XRESxYRES[-BPP][@REFRESH]
111 111
112 If the EP93xx video driver is built-in then th 112 If the EP93xx video driver is built-in then the video mode is set on
113 the Linux kernel command line, for example:: 113 the Linux kernel command line, for example::
114 114
115 video=ep93xx-fb:800x600-16@60 115 video=ep93xx-fb:800x600-16@60
116 116
117 If the EP93xx video driver is built as a modul 117 If the EP93xx video driver is built as a module then the video mode is
118 set when the module is installed:: 118 set when the module is installed::
119 119
120 modprobe ep93xx-fb video=320x240 120 modprobe ep93xx-fb video=320x240
121 121
122 ============== 122 ==============
123 Screenpage bug 123 Screenpage bug
124 ============== 124 ==============
125 125
126 At least on the EP9315 there is a silicon bug 126 At least on the EP9315 there is a silicon bug which causes bit 27 of
127 the VIDSCRNPAGE (framebuffer physical offset) 127 the VIDSCRNPAGE (framebuffer physical offset) to be tied low. There is
128 an unofficial errata for this bug at:: 128 an unofficial errata for this bug at::
129 129
130 https://marc.info/?l=linux-arm-kernel& 130 https://marc.info/?l=linux-arm-kernel&m=110061245502000&w=2
131 131
132 By default the EP93xx framebuffer driver check 132 By default the EP93xx framebuffer driver checks if the allocated physical
133 address has bit 27 set. If it does, then the m 133 address has bit 27 set. If it does, then the memory is freed and an
134 error is returned. The check can be disabled b 134 error is returned. The check can be disabled by adding the following
135 option when loading the driver:: 135 option when loading the driver::
136 136
137 ep93xx-fb.check_screenpage_bug=0 137 ep93xx-fb.check_screenpage_bug=0
138 138
139 In some cases it may be possible to reconfigur 139 In some cases it may be possible to reconfigure your SDRAM layout to
140 avoid this bug. See section 13 of the EP93xx u 140 avoid this bug. See section 13 of the EP93xx users' guide for details.
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