diff options
author | Russell King <rmk@dyn-67.arm.linux.org.uk> | 2008-12-29 13:08:11 -0500 |
---|---|---|
committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2008-12-29 13:08:11 -0500 |
commit | 47992cbdaef2f18a47871b2ed01ad27f568c8b73 (patch) | |
tree | bfed4f8c7ea3164afc75a85ab3624586c37c37f4 /Documentation | |
parent | 4655a0de36e8e903e99a8d152818e3aae86dae1a (diff) | |
parent | 198fc108ee4c2cd3f08954eae6a819c81c03214b (diff) |
Merge branch 'for-rmk' of git://git.kernel.org/pub/scm/linux/kernel/git/ycmiao/pxa-linux-2.6 into devel
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/arm/pxa/mfp.txt | 286 | ||||
-rw-r--r-- | Documentation/fb/pxafb.txt | 92 |
2 files changed, 376 insertions, 2 deletions
diff --git a/Documentation/arm/pxa/mfp.txt b/Documentation/arm/pxa/mfp.txt new file mode 100644 index 000000000000..a179e5bc02c9 --- /dev/null +++ b/Documentation/arm/pxa/mfp.txt | |||
@@ -0,0 +1,286 @@ | |||
1 | MFP Configuration for PXA2xx/PXA3xx Processors | ||
2 | |||
3 | Eric Miao <eric.miao@marvell.com> | ||
4 | |||
5 | MFP stands for Multi-Function Pin, which is the pin-mux logic on PXA3xx and | ||
6 | later PXA series processors. This document describes the existing MFP API, | ||
7 | and how board/platform driver authors could make use of it. | ||
8 | |||
9 | Basic Concept | ||
10 | =============== | ||
11 | |||
12 | Unlike the GPIO alternate function settings on PXA25x and PXA27x, a new MFP | ||
13 | mechanism is introduced from PXA3xx to completely move the pin-mux functions | ||
14 | out of the GPIO controller. In addition to pin-mux configurations, the MFP | ||
15 | also controls the low power state, driving strength, pull-up/down and event | ||
16 | detection of each pin. Below is a diagram of internal connections between | ||
17 | the MFP logic and the remaining SoC peripherals: | ||
18 | |||
19 | +--------+ | ||
20 | | |--(GPIO19)--+ | ||
21 | | GPIO | | | ||
22 | | |--(GPIO...) | | ||
23 | +--------+ | | ||
24 | | +---------+ | ||
25 | +--------+ +------>| | | ||
26 | | PWM2 |--(PWM_OUT)-------->| MFP | | ||
27 | +--------+ +------>| |-------> to external PAD | ||
28 | | +---->| | | ||
29 | +--------+ | | +-->| | | ||
30 | | SSP2 |---(TXD)----+ | | +---------+ | ||
31 | +--------+ | | | ||
32 | | | | ||
33 | +--------+ | | | ||
34 | | Keypad |--(MKOUT4)----+ | | ||
35 | +--------+ | | ||
36 | | | ||
37 | +--------+ | | ||
38 | | UART2 |---(TXD)--------+ | ||
39 | +--------+ | ||
40 | |||
41 | NOTE: the external pad is named as MFP_PIN_GPIO19, it doesn't necessarily | ||
42 | mean it's dedicated for GPIO19, only as a hint that internally this pin | ||
43 | can be routed from GPIO19 of the GPIO controller. | ||
44 | |||
45 | To better understand the change from PXA25x/PXA27x GPIO alternate function | ||
46 | to this new MFP mechanism, here are several key points: | ||
47 | |||
48 | 1. GPIO controller on PXA3xx is now a dedicated controller, same as other | ||
49 | internal controllers like PWM, SSP and UART, with 128 internal signals | ||
50 | which can be routed to external through one or more MFPs (e.g. GPIO<0> | ||
51 | can be routed through either MFP_PIN_GPIO0 as well as MFP_PIN_GPIO0_2, | ||
52 | see arch/arm/mach-pxa/mach/include/mfp-pxa300.h) | ||
53 | |||
54 | 2. Alternate function configuration is removed from this GPIO controller, | ||
55 | the remaining functions are pure GPIO-specific, i.e. | ||
56 | |||
57 | - GPIO signal level control | ||
58 | - GPIO direction control | ||
59 | - GPIO level change detection | ||
60 | |||
61 | 3. Low power state for each pin is now controlled by MFP, this means the | ||
62 | PGSRx registers on PXA2xx are now useless on PXA3xx | ||
63 | |||
64 | 4. Wakeup detection is now controlled by MFP, PWER does not control the | ||
65 | wakeup from GPIO(s) any more, depending on the sleeping state, ADxER | ||
66 | (as defined in pxa3xx-regs.h) controls the wakeup from MFP | ||
67 | |||
68 | NOTE: with such a clear separation of MFP and GPIO, by GPIO<xx> we normally | ||
69 | mean it is a GPIO signal, and by MFP<xxx> or pin xxx, we mean a physical | ||
70 | pad (or ball). | ||
71 | |||
72 | MFP API Usage | ||
73 | =============== | ||
74 | |||
75 | For board code writers, here are some guidelines: | ||
76 | |||
77 | 1. include ONE of the following header files in your <board>.c: | ||
78 | |||
79 | - #include <mach/mfp-pxa25x.h> | ||
80 | - #include <mach/mfp-pxa27x.h> | ||
81 | - #include <mach/mfp-pxa300.h> | ||
82 | - #include <mach/mfp-pxa320.h> | ||
83 | - #include <mach/mfp-pxa930.h> | ||
84 | |||
85 | NOTE: only one file in your <board>.c, depending on the processors used, | ||
86 | because pin configuration definitions may conflict in these file (i.e. | ||
87 | same name, different meaning and settings on different processors). E.g. | ||
88 | for zylonite platform, which support both PXA300/PXA310 and PXA320, two | ||
89 | separate files are introduced: zylonite_pxa300.c and zylonite_pxa320.c | ||
90 | (in addition to handle MFP configuration differences, they also handle | ||
91 | the other differences between the two combinations). | ||
92 | |||
93 | NOTE: PXA300 and PXA310 are almost identical in pin configurations (with | ||
94 | PXA310 supporting some additional ones), thus the difference is actually | ||
95 | covered in a single mfp-pxa300.h. | ||
96 | |||
97 | 2. prepare an array for the initial pin configurations, e.g.: | ||
98 | |||
99 | static unsigned long mainstone_pin_config[] __initdata = { | ||
100 | /* Chip Select */ | ||
101 | GPIO15_nCS_1, | ||
102 | |||
103 | /* LCD - 16bpp Active TFT */ | ||
104 | GPIOxx_TFT_LCD_16BPP, | ||
105 | GPIO16_PWM0_OUT, /* Backlight */ | ||
106 | |||
107 | /* MMC */ | ||
108 | GPIO32_MMC_CLK, | ||
109 | GPIO112_MMC_CMD, | ||
110 | GPIO92_MMC_DAT_0, | ||
111 | GPIO109_MMC_DAT_1, | ||
112 | GPIO110_MMC_DAT_2, | ||
113 | GPIO111_MMC_DAT_3, | ||
114 | |||
115 | ... | ||
116 | |||
117 | /* GPIO */ | ||
118 | GPIO1_GPIO | WAKEUP_ON_EDGE_BOTH, | ||
119 | }; | ||
120 | |||
121 | a) once the pin configurations are passed to pxa{2xx,3xx}_mfp_config(), | ||
122 | and written to the actual registers, they are useless and may discard, | ||
123 | adding '__initdata' will help save some additional bytes here. | ||
124 | |||
125 | b) when there is only one possible pin configurations for a component, | ||
126 | some simplified definitions can be used, e.g. GPIOxx_TFT_LCD_16BPP on | ||
127 | PXA25x and PXA27x processors | ||
128 | |||
129 | c) if by board design, a pin can be configured to wake up the system | ||
130 | from low power state, it can be 'OR'ed with any of: | ||
131 | |||
132 | WAKEUP_ON_EDGE_BOTH | ||
133 | WAKEUP_ON_EDGE_RISE | ||
134 | WAKEUP_ON_EDGE_FALL | ||
135 | WAKEUP_ON_LEVEL_HIGH - specifically for enabling of keypad GPIOs, | ||
136 | |||
137 | to indicate that this pin has the capability of wake-up the system, | ||
138 | and on which edge(s). This, however, doesn't necessarily mean the | ||
139 | pin _will_ wakeup the system, it will only when set_irq_wake() is | ||
140 | invoked with the corresponding GPIO IRQ (GPIO_IRQ(xx) or gpio_to_irq()) | ||
141 | and eventually calls gpio_set_wake() for the actual register setting. | ||
142 | |||
143 | d) although PXA3xx MFP supports edge detection on each pin, the | ||
144 | internal logic will only wakeup the system when those specific bits | ||
145 | in ADxER registers are set, which can be well mapped to the | ||
146 | corresponding peripheral, thus set_irq_wake() can be called with | ||
147 | the peripheral IRQ to enable the wakeup. | ||
148 | |||
149 | |||
150 | MFP on PXA3xx | ||
151 | =============== | ||
152 | |||
153 | Every external I/O pad on PXA3xx (excluding those for special purpose) has | ||
154 | one MFP logic associated, and is controlled by one MFP register (MFPR). | ||
155 | |||
156 | The MFPR has the following bit definitions (for PXA300/PXA310/PXA320): | ||
157 | |||
158 | 31 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 | ||
159 | +-------------------------+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ||
160 | | RESERVED |PS|PU|PD| DRIVE |SS|SD|SO|EC|EF|ER|--| AF_SEL | | ||
161 | +-------------------------+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ||
162 | |||
163 | Bit 3: RESERVED | ||
164 | Bit 4: EDGE_RISE_EN - enable detection of rising edge on this pin | ||
165 | Bit 5: EDGE_FALL_EN - enable detection of falling edge on this pin | ||
166 | Bit 6: EDGE_CLEAR - disable edge detection on this pin | ||
167 | Bit 7: SLEEP_OE_N - enable outputs during low power modes | ||
168 | Bit 8: SLEEP_DATA - output data on the pin during low power modes | ||
169 | Bit 9: SLEEP_SEL - selection control for low power modes signals | ||
170 | Bit 13: PULLDOWN_EN - enable the internal pull-down resistor on this pin | ||
171 | Bit 14: PULLUP_EN - enable the internal pull-up resistor on this pin | ||
172 | Bit 15: PULL_SEL - pull state controlled by selected alternate function | ||
173 | (0) or by PULL{UP,DOWN}_EN bits (1) | ||
174 | |||
175 | Bit 0 - 2: AF_SEL - alternate function selection, 8 possibilities, from 0-7 | ||
176 | Bit 10-12: DRIVE - drive strength and slew rate | ||
177 | 0b000 - fast 1mA | ||
178 | 0b001 - fast 2mA | ||
179 | 0b002 - fast 3mA | ||
180 | 0b003 - fast 4mA | ||
181 | 0b004 - slow 6mA | ||
182 | 0b005 - fast 6mA | ||
183 | 0b006 - slow 10mA | ||
184 | 0b007 - fast 10mA | ||
185 | |||
186 | MFP Design for PXA2xx/PXA3xx | ||
187 | ============================== | ||
188 | |||
189 | Due to the difference of pin-mux handling between PXA2xx and PXA3xx, a unified | ||
190 | MFP API is introduced to cover both series of processors. | ||
191 | |||
192 | The basic idea of this design is to introduce definitions for all possible pin | ||
193 | configurations, these definitions are processor and platform independent, and | ||
194 | the actual API invoked to convert these definitions into register settings and | ||
195 | make them effective there-after. | ||
196 | |||
197 | Files Involved | ||
198 | -------------- | ||
199 | |||
200 | - arch/arm/mach-pxa/include/mach/mfp.h | ||
201 | |||
202 | for | ||
203 | 1. Unified pin definitions - enum constants for all configurable pins | ||
204 | 2. processor-neutral bit definitions for a possible MFP configuration | ||
205 | |||
206 | - arch/arm/mach-pxa/include/mach/mfp-pxa3xx.h | ||
207 | |||
208 | for PXA3xx specific MFPR register bit definitions and PXA3xx common pin | ||
209 | configurations | ||
210 | |||
211 | - arch/arm/mach-pxa/include/mach/mfp-pxa2xx.h | ||
212 | |||
213 | for PXA2xx specific definitions and PXA25x/PXA27x common pin configurations | ||
214 | |||
215 | - arch/arm/mach-pxa/include/mach/mfp-pxa25x.h | ||
216 | arch/arm/mach-pxa/include/mach/mfp-pxa27x.h | ||
217 | arch/arm/mach-pxa/include/mach/mfp-pxa300.h | ||
218 | arch/arm/mach-pxa/include/mach/mfp-pxa320.h | ||
219 | arch/arm/mach-pxa/include/mach/mfp-pxa930.h | ||
220 | |||
221 | for processor specific definitions | ||
222 | |||
223 | - arch/arm/mach-pxa/mfp-pxa3xx.c | ||
224 | - arch/arm/mach-pxa/mfp-pxa2xx.c | ||
225 | |||
226 | for implementation of the pin configuration to take effect for the actual | ||
227 | processor. | ||
228 | |||
229 | Pin Configuration | ||
230 | ----------------- | ||
231 | |||
232 | The following comments are copied from mfp.h (see the actual source code | ||
233 | for most updated info) | ||
234 | |||
235 | /* | ||
236 | * a possible MFP configuration is represented by a 32-bit integer | ||
237 | * | ||
238 | * bit 0.. 9 - MFP Pin Number (1024 Pins Maximum) | ||
239 | * bit 10..12 - Alternate Function Selection | ||
240 | * bit 13..15 - Drive Strength | ||
241 | * bit 16..18 - Low Power Mode State | ||
242 | * bit 19..20 - Low Power Mode Edge Detection | ||
243 | * bit 21..22 - Run Mode Pull State | ||
244 | * | ||
245 | * to facilitate the definition, the following macros are provided | ||
246 | * | ||
247 | * MFP_CFG_DEFAULT - default MFP configuration value, with | ||
248 | * alternate function = 0, | ||
249 | * drive strength = fast 3mA (MFP_DS03X) | ||
250 | * low power mode = default | ||
251 | * edge detection = none | ||
252 | * | ||
253 | * MFP_CFG - default MFPR value with alternate function | ||
254 | * MFP_CFG_DRV - default MFPR value with alternate function and | ||
255 | * pin drive strength | ||
256 | * MFP_CFG_LPM - default MFPR value with alternate function and | ||
257 | * low power mode | ||
258 | * MFP_CFG_X - default MFPR value with alternate function, | ||
259 | * pin drive strength and low power mode | ||
260 | */ | ||
261 | |||
262 | Examples of pin configurations are: | ||
263 | |||
264 | #define GPIO94_SSP3_RXD MFP_CFG_X(GPIO94, AF1, DS08X, FLOAT) | ||
265 | |||
266 | which reads GPIO94 can be configured as SSP3_RXD, with alternate function | ||
267 | selection of 1, driving strength of 0b101, and a float state in low power | ||
268 | modes. | ||
269 | |||
270 | NOTE: this is the default setting of this pin being configured as SSP3_RXD | ||
271 | which can be modified a bit in board code, though it is not recommended to | ||
272 | do so, simply because this default setting is usually carefully encoded, | ||
273 | and is supposed to work in most cases. | ||
274 | |||
275 | Register Settings | ||
276 | ----------------- | ||
277 | |||
278 | Register settings on PXA3xx for a pin configuration is actually very | ||
279 | straight-forward, most bits can be converted directly into MFPR value | ||
280 | in a easier way. Two sets of MFPR values are calculated: the run-time | ||
281 | ones and the low power mode ones, to allow different settings. | ||
282 | |||
283 | The conversion from a generic pin configuration to the actual register | ||
284 | settings on PXA2xx is a bit complicated: many registers are involved, | ||
285 | including GAFRx, GPDRx, PGSRx, PWER, PKWR, PFER and PRER. Please see | ||
286 | mfp-pxa2xx.c for how the conversion is made. | ||
diff --git a/Documentation/fb/pxafb.txt b/Documentation/fb/pxafb.txt index db9b8500b43b..d143a0a749f9 100644 --- a/Documentation/fb/pxafb.txt +++ b/Documentation/fb/pxafb.txt | |||
@@ -5,9 +5,13 @@ The driver supports the following options, either via | |||
5 | options=<OPTIONS> when modular or video=pxafb:<OPTIONS> when built in. | 5 | options=<OPTIONS> when modular or video=pxafb:<OPTIONS> when built in. |
6 | 6 | ||
7 | For example: | 7 | For example: |
8 | modprobe pxafb options=mode:640x480-8,passive | 8 | modprobe pxafb options=vmem:2M,mode:640x480-8,passive |
9 | or on the kernel command line | 9 | or on the kernel command line |
10 | video=pxafb:mode:640x480-8,passive | 10 | video=pxafb:vmem:2M,mode:640x480-8,passive |
11 | |||
12 | vmem: VIDEO_MEM_SIZE | ||
13 | Amount of video memory to allocate (can be suffixed with K or M | ||
14 | for kilobytes or megabytes) | ||
11 | 15 | ||
12 | mode:XRESxYRES[-BPP] | 16 | mode:XRESxYRES[-BPP] |
13 | XRES == LCCR1_PPL + 1 | 17 | XRES == LCCR1_PPL + 1 |
@@ -52,3 +56,87 @@ outputen:POLARITY | |||
52 | pixclockpol:POLARITY | 56 | pixclockpol:POLARITY |
53 | pixel clock polarity | 57 | pixel clock polarity |
54 | 0 => falling edge, 1 => rising edge | 58 | 0 => falling edge, 1 => rising edge |
59 | |||
60 | |||
61 | Overlay Support for PXA27x and later LCD controllers | ||
62 | ==================================================== | ||
63 | |||
64 | PXA27x and later processors support overlay1 and overlay2 on-top of the | ||
65 | base framebuffer (although under-neath the base is also possible). They | ||
66 | support palette and no-palette RGB formats, as well as YUV formats (only | ||
67 | available on overlay2). These overlays have dedicated DMA channels and | ||
68 | behave in a similar way as a framebuffer. | ||
69 | |||
70 | However, there are some differences between these overlay framebuffers | ||
71 | and normal framebuffers, as listed below: | ||
72 | |||
73 | 1. overlay can start at a 32-bit word aligned position within the base | ||
74 | framebuffer, which means they have a start (x, y). This information | ||
75 | is encoded into var->nonstd (no, var->xoffset and var->yoffset are | ||
76 | not for such purpose). | ||
77 | |||
78 | 2. overlay framebuffer is allocated dynamically according to specified | ||
79 | 'struct fb_var_screeninfo', the amount is decided by: | ||
80 | |||
81 | var->xres_virtual * var->yres_virtual * bpp | ||
82 | |||
83 | bpp = 16 -- for RGB565 or RGBT555 | ||
84 | = 24 -- for YUV444 packed | ||
85 | = 24 -- for YUV444 planar | ||
86 | = 16 -- for YUV422 planar (1 pixel = 1 Y + 1/2 Cb + 1/2 Cr) | ||
87 | = 12 -- for YUV420 planar (1 pixel = 1 Y + 1/4 Cb + 1/4 Cr) | ||
88 | |||
89 | NOTE: | ||
90 | |||
91 | a. overlay does not support panning in x-direction, thus | ||
92 | var->xres_virtual will always be equal to var->xres | ||
93 | |||
94 | b. line length of overlay(s) must be on a 32-bit word boundary, | ||
95 | for YUV planar modes, it is a requirement for the component | ||
96 | with minimum bits per pixel, e.g. for YUV420, Cr component | ||
97 | for one pixel is actually 2-bits, it means the line length | ||
98 | should be a multiple of 16-pixels | ||
99 | |||
100 | c. starting horizontal position (XPOS) should start on a 32-bit | ||
101 | word boundary, otherwise the fb_check_var() will just fail. | ||
102 | |||
103 | d. the rectangle of the overlay should be within the base plane, | ||
104 | otherwise fail | ||
105 | |||
106 | Applications should follow the sequence below to operate an overlay | ||
107 | framebuffer: | ||
108 | |||
109 | a. open("/dev/fb[1-2]", ...) | ||
110 | b. ioctl(fd, FBIOGET_VSCREENINFO, ...) | ||
111 | c. modify 'var' with desired parameters: | ||
112 | 1) var->xres and var->yres | ||
113 | 2) larger var->yres_virtual if more memory is required, | ||
114 | usually for double-buffering | ||
115 | 3) var->nonstd for starting (x, y) and color format | ||
116 | 4) var->{red, green, blue, transp} if RGB mode is to be used | ||
117 | d. ioctl(fd, FBIOPUT_VSCREENINFO, ...) | ||
118 | e. ioctl(fd, FBIOGET_FSCREENINFO, ...) | ||
119 | f. mmap | ||
120 | g. ... | ||
121 | |||
122 | 3. for YUV planar formats, these are actually not supported within the | ||
123 | framebuffer framework, application has to take care of the offsets | ||
124 | and lengths of each component within the framebuffer. | ||
125 | |||
126 | 4. var->nonstd is used to pass starting (x, y) position and color format, | ||
127 | the detailed bit fields are shown below: | ||
128 | |||
129 | 31 23 20 10 0 | ||
130 | +-----------------+---+----------+----------+ | ||
131 | | ... unused ... |FOR| XPOS | YPOS | | ||
132 | +-----------------+---+----------+----------+ | ||
133 | |||
134 | FOR - color format, as defined by OVERLAY_FORMAT_* in pxafb.h | ||
135 | 0 - RGB | ||
136 | 1 - YUV444 PACKED | ||
137 | 2 - YUV444 PLANAR | ||
138 | 3 - YUV422 PLANAR | ||
139 | 4 - YUR420 PLANAR | ||
140 | |||
141 | XPOS - starting horizontal position | ||
142 | YPOS - starting vertical position | ||