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1 | ------------------------------------------------------------------------------- |
2 | HACKING | |
3 | ------------------------------------------------------------------------------- | |
4 | ||
5 | Coding style | |
6 | ------------ | |
7 | ||
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8 | This project is programmed using the Linux kernel coding style: |
9 | ||
10 | https://www.kernel.org/doc/html/latest/process/coding-style.html | |
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11 | |
12 | Please use the same style for any code contributions, thanks! | |
13 | ||
14 | ||
15 | Contributions | |
16 | ------------- | |
17 | ||
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18 | - In order to contribute you should ideally clone the git repository and |
19 | let us know (preferably via IRC, or via the mailing list) from where to | |
20 | pull/review your changes. You can use github.com, or any other public git | |
21 | hosting site. | |
22 | ||
23 | - Alternatively, patches can be sent to the development mailinglist at | |
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24 | sigrok-devel@lists.sourceforge.net (please subscribe to the list first). |
25 | ||
26 | https://lists.sourceforge.net/lists/listinfo/sigrok-devel | |
27 | ||
a2353f60 | 28 | |
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29 | Adding a new hardware driver |
30 | ---------------------------- | |
31 | ||
32 | The simple, scripted way (recommended): | |
33 | --------------------------------------- | |
34 | ||
35 | Use the 'new-driver' script from the sigrok-util repo: | |
36 | ||
37 | $ git clone git://sigrok.org/sigrok-util | |
38 | $ cd sigrok-util/source | |
39 | $ ./new-driver "Tondaj SL-814" | |
40 | ||
41 | The example above generates a patch file against the current libsigrok | |
42 | development git tree which adds a simple "stub" driver for your device | |
43 | (the Tondaj SL-814 sound level meter in this case). | |
44 | ||
45 | You can apply it like this: | |
46 | ||
47 | $ cd libsigrok | |
48 | $ git am 0001-tondaj-sl-814-Initial-driver-skeleton.patch | |
49 | ||
487c23fc | 50 | You can now edit the files in src/hardware/tondaj-sl-814 as needed |
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51 | and implement your driver based on the skeleton files there. That means your |
52 | patch submission later will consist of at least two patches: the initial one | |
53 | adding the skeleton driver, and one or more additional patches that actually | |
54 | implement the respective driver code. | |
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55 | |
56 | ||
57 | The manual way: | |
58 | --------------- | |
59 | ||
60 | This is a rough overview of what you need to do in order to add a new driver | |
61 | (using the Tondaj SL-814 device as example). It's basically what the | |
62 | 'new-driver' script (see above) does for you: | |
63 | ||
18037e79 GS |
64 | - Makefile.am: Add to src_libdrivers_la_SOURCES under the HW_TONDAJ_SL_814 |
65 | condition. | |
66 | - configure.ac: Add an SR_DRIVER() call. | |
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67 | - src/drivers.c: Add a tondaj_sl_814_driver_info entry in two places. |
68 | - src/hardware/tondaj-sl-814/ directory: Add api.c, protocol.c, protocol.h. | |
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69 | |
70 | See existing drivers or the 'new-driver' output for the details. | |
71 | ||
72 | ||
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73 | Random notes |
74 | ------------ | |
75 | ||
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76 | - Don't do variable declarations in compound statements, only at the |
77 | beginning of a function. | |
78 | ||
79 | - Generally avoid assigning values to variables at declaration time, | |
80 | especially so for complex and/or run-time dependent values. | |
81 | ||
c7e45562 | 82 | - Consistently use g_*malloc() / g_*malloc0(). Do not use standard |
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83 | malloc()/calloc() if it can be avoided (sometimes other libs such |
84 | as libftdi can return malloc()'d memory, for example). | |
85 | ||
86 | - Always properly match allocations with the proper *free() functions. If | |
c7e45562 | 87 | glib's g_*malloc()/g_*malloc0() was used, use g_free() to free the |
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88 | memory. Otherwise use standard free(). Never use the wrong function! |
89 | ||
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90 | - We assume that "small" memory allocations (< 1MB) will always succeed. |
91 | Thus, it's fine to use g_malloc() or g_malloc0() for allocations of | |
92 | simple/small structs and such (instead of using g_try_malloc()), and | |
93 | there's no need to check the return value. | |
94 | ||
95 | Do use g_try_malloc() or g_try_malloc0() for large (>= 1MB) allocations | |
96 | and check the return value. | |
a2353f60 | 97 | |
8ed26250 | 98 | - You should never print any messages (neither to stdout nor stderr nor |
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99 | elsewhere) "manually" via e.g. printf() or g_log() or similar functions. |
100 | Only sr_err()/sr_warn()/sr_info()/sr_dbg()/sr_spew() should be used. | |
101 | ||
102 | - Use glib's gboolean / TRUE / FALSE for boolean types consistently. | |
103 | Do not use <stdbool.h> and its true / false, and do not invent private | |
104 | definitions for this either. | |
105 | ||
106 | - Consistently use the same naming convention for #include guards in headers: | |
107 | <PROJECTNAME>_<PATH_TO_FILE>_<FILE> | |
108 | This ensures that all #include guards are always unique and consistent. | |
487c23fc | 109 | Example: LIBSIGROK_HARDWARE_MIC_985XX_PROTOCOL_H |
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110 | |
111 | - Consistently use the same naming convention for API functions: | |
112 | <libprefix>_<groupname>_<action>(). | |
113 | ||
114 | Examples: | |
115 | sr_log_loglevel_set(), sr_log_loglevel_get(), sr_log_handler_set(), | |
116 | sr_log_handler_set_default(), and so on. | |
117 | Or: | |
118 | sr_session_new(), sr_session_destroy(), sr_session_load(), and so on. | |
119 | ||
120 | Getter/setter function names should usually end with "_get" or "_set". | |
121 | Functions creating new "objects" should end with "_new". | |
122 | Functions destroying "objects" should end with "_destroy". | |
123 | Functions adding or removing items (e.g. from lists) should end with | |
124 | either "_add" or "_remove". | |
125 | Functions operating on all items from a list (not on only one of them), | |
126 | should end with "_all", e.g. "_remove_all", "_get_all", and so on. | |
127 | Use "_remove_all" in favor of "_clear" for consistency. | |
128 | ||
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129 | - All enums should generally use an explicit start number of 10000. |
130 | If there are multiple "categories" in the enum entries, each category | |
131 | should be 10000 entries apart from the next one. The start of categories | |
132 | are thus 10000, 20000, 30000, and so on. | |
133 | ||
134 | Adding items to an enum MUST always append to a "category", never add | |
135 | items in the middle of a category. The order of items MUST NOT be changed. | |
136 | Any of the above would break the ABI. | |
137 | ||
138 | The enum item 0 is special and is used as terminator in some lists, thus | |
139 | enums should not use this for "valid" entries (and start at 10000 instead). | |
140 | ||
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141 | |
142 | Doxygen | |
143 | ------- | |
144 | ||
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145 | - Use the @ notation for all Doxygen comments (e.g. @param, not \param). |
146 | ||
147 | - Do not use the @brief tag, it's unnecessary as we use JAVADOC_AUTOBRIEF. | |
148 | ||
149 | - Generally use the following item order in Doxygen comments: | |
150 | - Brief function description (1 line), followed by an empty line. | |
151 | - Optionally, a longer function description (and another empty line). | |
152 | - The list of parameter descriptions (@param). | |
153 | - The return value description (@return or @retval). | |
154 | - An optional @since tag (only for public SR_API functions). | |
155 | - An optional @private tag (for private SR_PRIV functions). | |
156 | ||
157 | - In @param lines, the name of the parameter is followed by a space and | |
158 | then a sentence describing the parameter (starts with a capital letter, | |
159 | ends with a full stop). | |
160 | ||
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161 | - In Doxygen comments, put an empty line between the block of @param lines |
162 | and the final @return line. The @param lines themselves (if there is more | |
163 | than one) are not separated by empty lines. | |
164 | ||
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165 | - Mark private functions (SR_PRIV) with /** @private */, so that Doxygen |
166 | doesn't include them in the output. Functions that are "static" anyway | |
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167 | don't need to be marked like this. Functions in non-public files that |
168 | are explicitly excluded in Doxyfile don't need to be marked either. | |
169 | Don't use @internal, always use @private instead. | |
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170 | |
171 | - Mark private variables/#defines with /** @cond PRIVATE */ and | |
172 | /** @endcond */, so that Doxygen doesn't include them in the output. | |
173 | Variables that are "static" don't need to be marked like this. | |
174 | ||
9fb5f2df | 175 | - Mark all public API functions (SR_API) with a @since tag which indicates |
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176 | in which release the respective function was added (e.g. "@since 0.1.0"). |
177 | ||
178 | If the function has existed before, but its API changed later, the @since | |
179 | tag should mention only the release when the API last changed. | |
180 | ||
181 | Example: The sr_foo() call was added in 0.1.0, but the API changed in | |
182 | the later 0.2.0 release. The docs should read "@since 0.2.0" in that case. | |
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183 | |
184 | Non-public functions (static ones, and those marked SR_PRIV) don't need | |
185 | to have @since markers. | |
186 | ||
187 | The @since tag should be the last one, i.e. it should come after @param, | |
188 | @return, @see, and so on. | |
189 | ||
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190 | - Examples: |
191 | ||
192 | /** | |
193 | * Tell a hardware driver to scan for devices. | |
194 | * | |
195 | * In addition to the detection, the devices that are found are also | |
196 | * initialized automatically. On some devices, this involves a firmware upload, | |
197 | * or other such measures. | |
198 | * | |
199 | * The order in which the system is scanned for devices is not specified. The | |
200 | * caller should not assume or rely on any specific order. | |
201 | * | |
202 | * Before calling sr_driver_scan(), the user must have previously initialized | |
203 | * the driver by calling sr_driver_init(). | |
204 | * | |
205 | * @param[in] driver The driver that should scan. Must be a pointer to one of | |
206 | * the entries returned by sr_driver_list(). Must not be NULL. | |
207 | * @param[in] options List of 'struct sr_hwopt' options to pass to the driver's | |
208 | * scanner. Can be NULL/empty. | |
209 | * | |
210 | * @return A GSList * of 'struct sr_dev_inst', or NULL if no devices were | |
211 | * found (or errors were encountered). This list must be freed by the | |
212 | * caller using g_slist_free(), but without freeing the data pointed | |
213 | * to in the list. | |
214 | * | |
215 | * @since 0.2.0 | |
216 | */ | |
217 | ||
218 | /** | |
219 | * Query value of a configuration key at the given driver or device instance. | |
220 | * | |
221 | * @param[in] driver The sr_dev_driver struct to query. Must not be NULL. | |
222 | * @param[in] sdi (optional) If the key is specific to a device, this must | |
223 | * contain a pointer to the struct sr_dev_inst to be checked. | |
224 | * Otherwise it must be NULL. If sdi is != NULL, sdi->priv must | |
225 | * also be != NULL. | |
226 | * @param[in,out] data Pointer to a GVariant where the value will be stored. | |
227 | * Must not be NULL. The caller is given ownership of the GVariant | |
228 | * and must thus decrease the refcount after use. However if | |
229 | * this function returns an error code, the field should be | |
230 | * considered unused, and should not be unreferenced. | |
231 | * | |
232 | * @retval SR_OK Success. | |
233 | * @retval SR_ERR Error. | |
234 | * @retval SR_ERR_ARG The driver doesn't know that key, but this is not to be | |
235 | * interpreted as an error by the caller; merely as an indication | |
236 | * that it's not applicable. | |
237 | * | |
238 | * @since 0.3.0 | |
239 | * @private | |
240 | */ | |
241 | ||
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243 | Testsuite |
244 | --------- | |
245 | ||
246 | You can run the libsigrok testsuite using: | |
247 | ||
248 | $ make check | |
249 | ||
250 | ||
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251 | Release engineering |
252 | ------------------- | |
253 | ||
254 | See | |
255 | ||
256 | http://sigrok.org/wiki/Developers/Release_process | |
257 | ||
258 | for a list of items that need to be done when releasing a new tarball. | |
259 |