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authorTrond Myklebust <Trond.Myklebust@netapp.com>2006-06-20 20:46:21 -0400
committerTrond Myklebust <Trond.Myklebust@netapp.com>2006-06-20 20:46:21 -0400
commit70ac4385a13f78bc478f26d317511893741b05bd (patch)
treedafc7f3018295fc4ee00339889e4f35d5b9d7743 /Documentation
parentd59bf96cdde5b874a57bfd1425faa45da915d0b7 (diff)
parent077e98945db7e54a9865b5f29a1f02f531eca414 (diff)
Merge branch 'master' of /home/trondmy/kernel/linux-2.6/
Conflicts: include/linux/nfs_fs.h Fixed up conflict with kernel header updates.
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/arm/Sharp-LH/ADC-LH7-Touchscreen61
-rw-r--r--Documentation/arm/Sharp-LH/LCDPanels59
-rw-r--r--Documentation/filesystems/inotify.txt130
3 files changed, 244 insertions, 6 deletions
diff --git a/Documentation/arm/Sharp-LH/ADC-LH7-Touchscreen b/Documentation/arm/Sharp-LH/ADC-LH7-Touchscreen
new file mode 100644
index 000000000000..1e6a23fdf2fc
--- /dev/null
+++ b/Documentation/arm/Sharp-LH/ADC-LH7-Touchscreen
@@ -0,0 +1,61 @@
1README on the ADC/Touchscreen Controller
2========================================
3
4The LH79524 and LH7A404 include a built-in Analog to Digital
5controller (ADC) that is used to process input from a touchscreen.
6The driver only implements a four-wire touch panel protocol.
7
8The touchscreen driver is maintenance free except for the pen-down or
9touch threshold. Some resistive displays and board combinations may
10require tuning of this threshold. The driver exposes some of it's
11internal state in the sys filesystem. If the kernel is configured
12with it, CONFIG_SYSFS, and sysfs is mounted at /sys, there will be a
13directory
14
15 /sys/devices/platform/adc-lh7.0
16
17containing these files.
18
19 -r--r--r-- 1 root root 4096 Jan 1 00:00 samples
20 -rw-r--r-- 1 root root 4096 Jan 1 00:00 threshold
21 -r--r--r-- 1 root root 4096 Jan 1 00:00 threshold_range
22
23The threshold is the current touch threshold. It defaults to 750 on
24most targets.
25
26 # cat threshold
27 750
28
29The threshold_range contains the range of valid values for the
30threshold. Values outside of this range will be silently ignored.
31
32 # cat threshold_range
33 0 1023
34
35To change the threshold, write a value to the threshold file.
36
37 # echo 500 > threshold
38 # cat threshold
39 500
40
41The samples file contains the most recently sampled values from the
42ADC. There are 12. Below are typical of the last sampled values when
43the pen has been released. The first two and last two samples are for
44detecting whether or not the pen is down. The third through sixth are
45X coordinate samples. The seventh through tenth are Y coordinate
46samples.
47
48 # cat samples
49 1023 1023 0 0 0 0 530 529 530 529 1023 1023
50
51To determine a reasonable threshold, press on the touch panel with an
52appropriate stylus and read the values from samples.
53
54 # cat samples
55 1023 676 92 103 101 102 855 919 922 922 1023 679
56
57The first and eleventh samples are discarded. Thus, the important
58values are the second and twelfth which are used to determine if the
59pen is down. When both are below the threshold, the driver registers
60that the pen is down. When either is above the threshold, it
61registers then pen is up.
diff --git a/Documentation/arm/Sharp-LH/LCDPanels b/Documentation/arm/Sharp-LH/LCDPanels
new file mode 100644
index 000000000000..fb1b21c2f2f4
--- /dev/null
+++ b/Documentation/arm/Sharp-LH/LCDPanels
@@ -0,0 +1,59 @@
1README on the LCD Panels
2========================
3
4Configuration options for several LCD panels, available from Logic PD,
5are included in the kernel source. This README will help you
6understand the configuration data and give you some guidance for
7adding support for other panels if you wish.
8
9
10lcd-panels.h
11------------
12
13There is no way, at present, to detect which panel is attached to the
14system at runtime. Thus the kernel configuration is static. The file
15arch/arm/mach-ld7a40x/lcd-panels.h (or similar) defines all of the
16panel specific parameters.
17
18It should be possible for this data to be shared among several device
19families. The current layout may be insufficiently general, but it is
20amenable to improvement.
21
22
23PIXEL_CLOCK
24-----------
25
26The panel data sheets will give a range of acceptable pixel clocks.
27The fundamental LCDCLK input frequency is divided down by a PCD
28constant in field '.tim2'. It may happen that it is impossible to set
29the pixel clock within this range. A clock which is too slow will
30tend to flicker. For the highest quality image, set the clock as high
31as possible.
32
33
34MARGINS
35-------
36
37These values may be difficult to glean from the panel data sheet. In
38the case of the Sharp panels, the upper margin is explicitly called
39out as a specific number of lines from the top of the frame. The
40other values may not matter as much as the panels tend to
41automatically center the image.
42
43
44Sync Sense
45----------
46
47The sense of the hsync and vsync pulses may be called out in the data
48sheet. On one panel, the sense of these pulses determine the height
49of the visible region on the panel. Most of the Sharp panels use
50negative sense sync pulses set by the TIM2_IHS and TIM2_IVS bits in
51'.tim2'.
52
53
54Pel Layout
55----------
56
57The Sharp color TFT panels are all configured for 16 bit direct color
58modes. The amba-lcd driver sets the pel mode to 565 for 5 bits of
59each red and blue and 6 bits of green.
diff --git a/Documentation/filesystems/inotify.txt b/Documentation/filesystems/inotify.txt
index 6d501903f68e..59a919f16144 100644
--- a/Documentation/filesystems/inotify.txt
+++ b/Documentation/filesystems/inotify.txt
@@ -69,17 +69,135 @@ Prototypes:
69 int inotify_rm_watch (int fd, __u32 mask); 69 int inotify_rm_watch (int fd, __u32 mask);
70 70
71 71
72(iii) Internal Kernel Implementation 72(iii) Kernel Interface
73 73
74Each inotify instance is associated with an inotify_device structure. 74Inotify's kernel API consists a set of functions for managing watches and an
75event callback.
76
77To use the kernel API, you must first initialize an inotify instance with a set
78of inotify_operations. You are given an opaque inotify_handle, which you use
79for any further calls to inotify.
80
81 struct inotify_handle *ih = inotify_init(my_event_handler);
82
83You must provide a function for processing events and a function for destroying
84the inotify watch.
85
86 void handle_event(struct inotify_watch *watch, u32 wd, u32 mask,
87 u32 cookie, const char *name, struct inode *inode)
88
89 watch - the pointer to the inotify_watch that triggered this call
90 wd - the watch descriptor
91 mask - describes the event that occurred
92 cookie - an identifier for synchronizing events
93 name - the dentry name for affected files in a directory-based event
94 inode - the affected inode in a directory-based event
95
96 void destroy_watch(struct inotify_watch *watch)
97
98You may add watches by providing a pre-allocated and initialized inotify_watch
99structure and specifying the inode to watch along with an inotify event mask.
100You must pin the inode during the call. You will likely wish to embed the
101inotify_watch structure in a structure of your own which contains other
102information about the watch. Once you add an inotify watch, it is immediately
103subject to removal depending on filesystem events. You must grab a reference if
104you depend on the watch hanging around after the call.
105
106 inotify_init_watch(&my_watch->iwatch);
107 inotify_get_watch(&my_watch->iwatch); // optional
108 s32 wd = inotify_add_watch(ih, &my_watch->iwatch, inode, mask);
109 inotify_put_watch(&my_watch->iwatch); // optional
110
111You may use the watch descriptor (wd) or the address of the inotify_watch for
112other inotify operations. You must not directly read or manipulate data in the
113inotify_watch. Additionally, you must not call inotify_add_watch() more than
114once for a given inotify_watch structure, unless you have first called either
115inotify_rm_watch() or inotify_rm_wd().
116
117To determine if you have already registered a watch for a given inode, you may
118call inotify_find_watch(), which gives you both the wd and the watch pointer for
119the inotify_watch, or an error if the watch does not exist.
120
121 wd = inotify_find_watch(ih, inode, &watchp);
122
123You may use container_of() on the watch pointer to access your own data
124associated with a given watch. When an existing watch is found,
125inotify_find_watch() bumps the refcount before releasing its locks. You must
126put that reference with:
127
128 put_inotify_watch(watchp);
129
130Call inotify_find_update_watch() to update the event mask for an existing watch.
131inotify_find_update_watch() returns the wd of the updated watch, or an error if
132the watch does not exist.
133
134 wd = inotify_find_update_watch(ih, inode, mask);
135
136An existing watch may be removed by calling either inotify_rm_watch() or
137inotify_rm_wd().
138
139 int ret = inotify_rm_watch(ih, &my_watch->iwatch);
140 int ret = inotify_rm_wd(ih, wd);
141
142A watch may be removed while executing your event handler with the following:
143
144 inotify_remove_watch_locked(ih, iwatch);
145
146Call inotify_destroy() to remove all watches from your inotify instance and
147release it. If there are no outstanding references, inotify_destroy() will call
148your destroy_watch op for each watch.
149
150 inotify_destroy(ih);
151
152When inotify removes a watch, it sends an IN_IGNORED event to your callback.
153You may use this event as an indication to free the watch memory. Note that
154inotify may remove a watch due to filesystem events, as well as by your request.
155If you use IN_ONESHOT, inotify will remove the watch after the first event, at
156which point you may call the final inotify_put_watch.
157
158(iv) Kernel Interface Prototypes
159
160 struct inotify_handle *inotify_init(struct inotify_operations *ops);
161
162 inotify_init_watch(struct inotify_watch *watch);
163
164 s32 inotify_add_watch(struct inotify_handle *ih,
165 struct inotify_watch *watch,
166 struct inode *inode, u32 mask);
167
168 s32 inotify_find_watch(struct inotify_handle *ih, struct inode *inode,
169 struct inotify_watch **watchp);
170
171 s32 inotify_find_update_watch(struct inotify_handle *ih,
172 struct inode *inode, u32 mask);
173
174 int inotify_rm_wd(struct inotify_handle *ih, u32 wd);
175
176 int inotify_rm_watch(struct inotify_handle *ih,
177 struct inotify_watch *watch);
178
179 void inotify_remove_watch_locked(struct inotify_handle *ih,
180 struct inotify_watch *watch);
181
182 void inotify_destroy(struct inotify_handle *ih);
183
184 void get_inotify_watch(struct inotify_watch *watch);
185 void put_inotify_watch(struct inotify_watch *watch);
186
187
188(v) Internal Kernel Implementation
189
190Each inotify instance is represented by an inotify_handle structure.
191Inotify's userspace consumers also have an inotify_device which is
192associated with the inotify_handle, and on which events are queued.
75 193
76Each watch is associated with an inotify_watch structure. Watches are chained 194Each watch is associated with an inotify_watch structure. Watches are chained
77off of each associated device and each associated inode. 195off of each associated inotify_handle and each associated inode.
78 196
79See fs/inotify.c for the locking and lifetime rules. 197See fs/inotify.c and fs/inotify_user.c for the locking and lifetime rules.
80 198
81 199
82(iv) Rationale 200(vi) Rationale
83 201
84Q: What is the design decision behind not tying the watch to the open fd of 202Q: What is the design decision behind not tying the watch to the open fd of
85 the watched object? 203 the watched object?
@@ -145,7 +263,7 @@ A: The poor user-space interface is the second biggest problem with dnotify.
145 file descriptor-based one that allows basic file I/O and poll/select. 263 file descriptor-based one that allows basic file I/O and poll/select.
146 Obtaining the fd and managing the watches could have been done either via a 264 Obtaining the fd and managing the watches could have been done either via a
147 device file or a family of new system calls. We decided to implement a 265 device file or a family of new system calls. We decided to implement a
148 family of system calls because that is the preffered approach for new kernel 266 family of system calls because that is the preferred approach for new kernel
149 interfaces. The only real difference was whether we wanted to use open(2) 267 interfaces. The only real difference was whether we wanted to use open(2)
150 and ioctl(2) or a couple of new system calls. System calls beat ioctls. 268 and ioctl(2) or a couple of new system calls. System calls beat ioctls.
151 269