1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Flex Timer Module Quadrature decoder |
4 | * |
5 | * This module implements a driver for decoding the FTM quadrature |
6 | * of ex. a LS1021A |
7 | */ |
8 | |
9 | #include <linux/fsl/ftm.h> |
10 | #include <linux/module.h> |
11 | #include <linux/platform_device.h> |
12 | #include <linux/of.h> |
13 | #include <linux/io.h> |
14 | #include <linux/mutex.h> |
15 | #include <linux/counter.h> |
16 | #include <linux/bitfield.h> |
17 | #include <linux/types.h> |
18 | |
19 | #define FTM_FIELD_UPDATE(ftm, offset, mask, val) \ |
20 | ({ \ |
21 | uint32_t flags; \ |
22 | ftm_read(ftm, offset, &flags); \ |
23 | flags &= ~mask; \ |
24 | flags |= FIELD_PREP(mask, val); \ |
25 | ftm_write(ftm, offset, flags); \ |
26 | }) |
27 | |
28 | struct ftm_quaddec { |
29 | struct platform_device *pdev; |
30 | void __iomem *ftm_base; |
31 | bool big_endian; |
32 | struct mutex ftm_quaddec_mutex; |
33 | }; |
34 | |
35 | static void ftm_read(struct ftm_quaddec *ftm, uint32_t offset, uint32_t *data) |
36 | { |
37 | if (ftm->big_endian) |
38 | *data = ioread32be(ftm->ftm_base + offset); |
39 | else |
40 | *data = ioread32(ftm->ftm_base + offset); |
41 | } |
42 | |
43 | static void ftm_write(struct ftm_quaddec *ftm, uint32_t offset, uint32_t data) |
44 | { |
45 | if (ftm->big_endian) |
46 | iowrite32be(data, ftm->ftm_base + offset); |
47 | else |
48 | iowrite32(data, ftm->ftm_base + offset); |
49 | } |
50 | |
51 | /* Hold mutex before modifying write protection state */ |
52 | static void ftm_clear_write_protection(struct ftm_quaddec *ftm) |
53 | { |
54 | uint32_t flag; |
55 | |
56 | /* First see if it is enabled */ |
57 | ftm_read(ftm, FTM_FMS, data: &flag); |
58 | |
59 | if (flag & FTM_FMS_WPEN) |
60 | FTM_FIELD_UPDATE(ftm, FTM_MODE, FTM_MODE_WPDIS, 1); |
61 | } |
62 | |
63 | static void ftm_set_write_protection(struct ftm_quaddec *ftm) |
64 | { |
65 | FTM_FIELD_UPDATE(ftm, FTM_FMS, FTM_FMS_WPEN, 1); |
66 | } |
67 | |
68 | static void ftm_reset_counter(struct ftm_quaddec *ftm) |
69 | { |
70 | /* Reset hardware counter to CNTIN */ |
71 | ftm_write(ftm, FTM_CNT, data: 0x0); |
72 | } |
73 | |
74 | static void ftm_quaddec_init(struct ftm_quaddec *ftm) |
75 | { |
76 | ftm_clear_write_protection(ftm); |
77 | |
78 | /* |
79 | * Do not write in the region from the CNTIN register through the |
80 | * PWMLOAD register when FTMEN = 0. |
81 | * Also reset other fields to zero |
82 | */ |
83 | ftm_write(ftm, FTM_MODE, FTM_MODE_FTMEN); |
84 | ftm_write(ftm, FTM_CNTIN, data: 0x0000); |
85 | ftm_write(ftm, FTM_MOD, data: 0xffff); |
86 | ftm_write(ftm, FTM_CNT, data: 0x0); |
87 | /* Set prescaler, reset other fields to zero */ |
88 | ftm_write(ftm, FTM_SC, FTM_SC_PS_1); |
89 | |
90 | /* Select quad mode, reset other fields to zero */ |
91 | ftm_write(ftm, FTM_QDCTRL, FTM_QDCTRL_QUADEN); |
92 | |
93 | /* Unused features and reset to default section */ |
94 | ftm_write(ftm, FTM_POL, data: 0x0); |
95 | ftm_write(ftm, FTM_FLTCTRL, data: 0x0); |
96 | ftm_write(ftm, FTM_SYNCONF, data: 0x0); |
97 | ftm_write(ftm, FTM_SYNC, data: 0xffff); |
98 | |
99 | /* Lock the FTM */ |
100 | ftm_set_write_protection(ftm); |
101 | } |
102 | |
103 | static void ftm_quaddec_disable(void *ftm) |
104 | { |
105 | struct ftm_quaddec *ftm_qua = ftm; |
106 | |
107 | ftm_clear_write_protection(ftm: ftm_qua); |
108 | ftm_write(ftm: ftm_qua, FTM_MODE, data: 0); |
109 | ftm_write(ftm: ftm_qua, FTM_QDCTRL, data: 0); |
110 | /* |
111 | * This is enough to disable the counter. No clock has been |
112 | * selected by writing to FTM_SC in init() |
113 | */ |
114 | ftm_set_write_protection(ftm: ftm_qua); |
115 | } |
116 | |
117 | static int ftm_quaddec_get_prescaler(struct counter_device *counter, |
118 | struct counter_count *count, u32 *cnt_mode) |
119 | { |
120 | struct ftm_quaddec *ftm = counter_priv(counter); |
121 | uint32_t scflags; |
122 | |
123 | ftm_read(ftm, FTM_SC, data: &scflags); |
124 | |
125 | *cnt_mode = FIELD_GET(FTM_SC_PS_MASK, scflags); |
126 | |
127 | return 0; |
128 | } |
129 | |
130 | static int ftm_quaddec_set_prescaler(struct counter_device *counter, |
131 | struct counter_count *count, u32 cnt_mode) |
132 | { |
133 | struct ftm_quaddec *ftm = counter_priv(counter); |
134 | |
135 | mutex_lock(&ftm->ftm_quaddec_mutex); |
136 | |
137 | ftm_clear_write_protection(ftm); |
138 | FTM_FIELD_UPDATE(ftm, FTM_SC, FTM_SC_PS_MASK, cnt_mode); |
139 | ftm_set_write_protection(ftm); |
140 | |
141 | /* Also resets the counter as it is undefined anyway now */ |
142 | ftm_reset_counter(ftm); |
143 | |
144 | mutex_unlock(lock: &ftm->ftm_quaddec_mutex); |
145 | return 0; |
146 | } |
147 | |
148 | static const char * const ftm_quaddec_prescaler[] = { |
149 | "1" , "2" , "4" , "8" , "16" , "32" , "64" , "128" |
150 | }; |
151 | |
152 | static const enum counter_synapse_action ftm_quaddec_synapse_actions[] = { |
153 | COUNTER_SYNAPSE_ACTION_BOTH_EDGES |
154 | }; |
155 | |
156 | static const enum counter_function ftm_quaddec_count_functions[] = { |
157 | COUNTER_FUNCTION_QUADRATURE_X4 |
158 | }; |
159 | |
160 | static int ftm_quaddec_count_read(struct counter_device *counter, |
161 | struct counter_count *count, |
162 | u64 *val) |
163 | { |
164 | struct ftm_quaddec *const ftm = counter_priv(counter); |
165 | uint32_t cntval; |
166 | |
167 | ftm_read(ftm, FTM_CNT, data: &cntval); |
168 | |
169 | *val = cntval; |
170 | |
171 | return 0; |
172 | } |
173 | |
174 | static int ftm_quaddec_count_write(struct counter_device *counter, |
175 | struct counter_count *count, |
176 | const u64 val) |
177 | { |
178 | struct ftm_quaddec *const ftm = counter_priv(counter); |
179 | |
180 | if (val != 0) { |
181 | dev_warn(&ftm->pdev->dev, "Can only accept '0' as new counter value\n" ); |
182 | return -EINVAL; |
183 | } |
184 | |
185 | ftm_reset_counter(ftm); |
186 | |
187 | return 0; |
188 | } |
189 | |
190 | static int ftm_quaddec_count_function_read(struct counter_device *counter, |
191 | struct counter_count *count, |
192 | enum counter_function *function) |
193 | { |
194 | *function = COUNTER_FUNCTION_QUADRATURE_X4; |
195 | |
196 | return 0; |
197 | } |
198 | |
199 | static int ftm_quaddec_action_read(struct counter_device *counter, |
200 | struct counter_count *count, |
201 | struct counter_synapse *synapse, |
202 | enum counter_synapse_action *action) |
203 | { |
204 | *action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES; |
205 | |
206 | return 0; |
207 | } |
208 | |
209 | static const struct counter_ops ftm_quaddec_cnt_ops = { |
210 | .count_read = ftm_quaddec_count_read, |
211 | .count_write = ftm_quaddec_count_write, |
212 | .function_read = ftm_quaddec_count_function_read, |
213 | .action_read = ftm_quaddec_action_read, |
214 | }; |
215 | |
216 | static struct counter_signal ftm_quaddec_signals[] = { |
217 | { |
218 | .id = 0, |
219 | .name = "Channel 1 Phase A" |
220 | }, |
221 | { |
222 | .id = 1, |
223 | .name = "Channel 1 Phase B" |
224 | } |
225 | }; |
226 | |
227 | static struct counter_synapse ftm_quaddec_count_synapses[] = { |
228 | { |
229 | .actions_list = ftm_quaddec_synapse_actions, |
230 | .num_actions = ARRAY_SIZE(ftm_quaddec_synapse_actions), |
231 | .signal = &ftm_quaddec_signals[0] |
232 | }, |
233 | { |
234 | .actions_list = ftm_quaddec_synapse_actions, |
235 | .num_actions = ARRAY_SIZE(ftm_quaddec_synapse_actions), |
236 | .signal = &ftm_quaddec_signals[1] |
237 | } |
238 | }; |
239 | |
240 | static DEFINE_COUNTER_ENUM(ftm_quaddec_prescaler_enum, ftm_quaddec_prescaler); |
241 | |
242 | static struct counter_comp ftm_quaddec_count_ext[] = { |
243 | COUNTER_COMP_COUNT_ENUM("prescaler" , ftm_quaddec_get_prescaler, |
244 | ftm_quaddec_set_prescaler, |
245 | ftm_quaddec_prescaler_enum), |
246 | }; |
247 | |
248 | static struct counter_count ftm_quaddec_counts = { |
249 | .id = 0, |
250 | .name = "Channel 1 Count" , |
251 | .functions_list = ftm_quaddec_count_functions, |
252 | .num_functions = ARRAY_SIZE(ftm_quaddec_count_functions), |
253 | .synapses = ftm_quaddec_count_synapses, |
254 | .num_synapses = ARRAY_SIZE(ftm_quaddec_count_synapses), |
255 | .ext = ftm_quaddec_count_ext, |
256 | .num_ext = ARRAY_SIZE(ftm_quaddec_count_ext) |
257 | }; |
258 | |
259 | static int ftm_quaddec_probe(struct platform_device *pdev) |
260 | { |
261 | struct counter_device *counter; |
262 | struct ftm_quaddec *ftm; |
263 | |
264 | struct device_node *node = pdev->dev.of_node; |
265 | struct resource *io; |
266 | int ret; |
267 | |
268 | counter = devm_counter_alloc(dev: &pdev->dev, sizeof_priv: sizeof(*ftm)); |
269 | if (!counter) |
270 | return -ENOMEM; |
271 | ftm = counter_priv(counter); |
272 | |
273 | io = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
274 | if (!io) { |
275 | dev_err(&pdev->dev, "Failed to get memory region\n" ); |
276 | return -ENODEV; |
277 | } |
278 | |
279 | ftm->pdev = pdev; |
280 | ftm->big_endian = of_property_read_bool(np: node, propname: "big-endian" ); |
281 | ftm->ftm_base = devm_ioremap(dev: &pdev->dev, offset: io->start, size: resource_size(res: io)); |
282 | |
283 | if (!ftm->ftm_base) { |
284 | dev_err(&pdev->dev, "Failed to map memory region\n" ); |
285 | return -EINVAL; |
286 | } |
287 | counter->name = dev_name(dev: &pdev->dev); |
288 | counter->parent = &pdev->dev; |
289 | counter->ops = &ftm_quaddec_cnt_ops; |
290 | counter->counts = &ftm_quaddec_counts; |
291 | counter->num_counts = 1; |
292 | counter->signals = ftm_quaddec_signals; |
293 | counter->num_signals = ARRAY_SIZE(ftm_quaddec_signals); |
294 | |
295 | mutex_init(&ftm->ftm_quaddec_mutex); |
296 | |
297 | ftm_quaddec_init(ftm); |
298 | |
299 | ret = devm_add_action_or_reset(&pdev->dev, ftm_quaddec_disable, ftm); |
300 | if (ret) |
301 | return ret; |
302 | |
303 | ret = devm_counter_add(dev: &pdev->dev, counter); |
304 | if (ret) |
305 | return dev_err_probe(dev: &pdev->dev, err: ret, fmt: "Failed to add counter\n" ); |
306 | |
307 | return 0; |
308 | } |
309 | |
310 | static const struct of_device_id ftm_quaddec_match[] = { |
311 | { .compatible = "fsl,ftm-quaddec" }, |
312 | {}, |
313 | }; |
314 | |
315 | static struct platform_driver ftm_quaddec_driver = { |
316 | .driver = { |
317 | .name = "ftm-quaddec" , |
318 | .of_match_table = ftm_quaddec_match, |
319 | }, |
320 | .probe = ftm_quaddec_probe, |
321 | }; |
322 | |
323 | module_platform_driver(ftm_quaddec_driver); |
324 | |
325 | MODULE_LICENSE("GPL" ); |
326 | MODULE_AUTHOR("Kjeld Flarup <kfa@deif.com>" ); |
327 | MODULE_AUTHOR("Patrick Havelange <patrick.havelange@essensium.com>" ); |
328 | MODULE_IMPORT_NS(COUNTER); |
329 | |