1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * GPIO driver for the ACCES 104-DIO-48E series
4  * Copyright (C) 2016 William Breathitt Gray
5  *
6  * This driver supports the following ACCES devices: 104-DIO-48E and
7  * 104-DIO-24E.
8  */
9 #include <linux/bits.h>
10 #include <linux/device.h>
11 #include <linux/err.h>
12 #include <linux/i8254.h>
13 #include <linux/ioport.h>
14 #include <linux/irq.h>
15 #include <linux/isa.h>
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/moduleparam.h>
19 #include <linux/regmap.h>
20 #include <linux/spinlock.h>
21 #include <linux/types.h>
22 
23 #include "gpio-i8255.h"
24 
25 MODULE_IMPORT_NS(I8255);
26 
27 #define DIO48E_EXTENT 16
28 #define MAX_NUM_DIO48E max_num_isa_dev(DIO48E_EXTENT)
29 
30 static unsigned int base[MAX_NUM_DIO48E];
31 static unsigned int num_dio48e;
32 module_param_hw_array(base, uint, ioport, &num_dio48e, 0);
33 MODULE_PARM_DESC(base, "ACCES 104-DIO-48E base addresses");
34 
35 static unsigned int irq[MAX_NUM_DIO48E];
36 static unsigned int num_irq;
37 module_param_hw_array(irq, uint, irq, &num_irq, 0);
38 MODULE_PARM_DESC(irq, "ACCES 104-DIO-48E interrupt line numbers");
39 
40 #define DIO48E_ENABLE_INTERRUPT 0xB
41 #define DIO48E_DISABLE_INTERRUPT DIO48E_ENABLE_INTERRUPT
42 #define DIO48E_ENABLE_COUNTER_TIMER_ADDRESSING 0xD
43 #define DIO48E_DISABLE_COUNTER_TIMER_ADDRESSING DIO48E_ENABLE_COUNTER_TIMER_ADDRESSING
44 #define DIO48E_CLEAR_INTERRUPT 0xF
45 
46 #define DIO48E_NUM_PPI 2
47 
48 static const struct regmap_range dio48e_wr_ranges[] = {
49 	regmap_reg_range(0x0, 0x9), regmap_reg_range(0xB, 0xB),
50 	regmap_reg_range(0xD, 0xD), regmap_reg_range(0xF, 0xF),
51 };
52 static const struct regmap_range dio48e_rd_ranges[] = {
53 	regmap_reg_range(0x0, 0x2), regmap_reg_range(0x4, 0x6),
54 	regmap_reg_range(0xB, 0xB), regmap_reg_range(0xD, 0xD),
55 	regmap_reg_range(0xF, 0xF),
56 };
57 static const struct regmap_range dio48e_volatile_ranges[] = {
58 	i8255_volatile_regmap_range(0x0), i8255_volatile_regmap_range(0x4),
59 	regmap_reg_range(0xB, 0xB), regmap_reg_range(0xD, 0xD),
60 	regmap_reg_range(0xF, 0xF),
61 };
62 static const struct regmap_range dio48e_precious_ranges[] = {
63 	regmap_reg_range(0xB, 0xB), regmap_reg_range(0xD, 0xD),
64 	regmap_reg_range(0xF, 0xF),
65 };
66 static const struct regmap_access_table dio48e_wr_table = {
67 	.yes_ranges = dio48e_wr_ranges,
68 	.n_yes_ranges = ARRAY_SIZE(dio48e_wr_ranges),
69 };
70 static const struct regmap_access_table dio48e_rd_table = {
71 	.yes_ranges = dio48e_rd_ranges,
72 	.n_yes_ranges = ARRAY_SIZE(dio48e_rd_ranges),
73 };
74 static const struct regmap_access_table dio48e_volatile_table = {
75 	.yes_ranges = dio48e_volatile_ranges,
76 	.n_yes_ranges = ARRAY_SIZE(dio48e_volatile_ranges),
77 };
78 static const struct regmap_access_table dio48e_precious_table = {
79 	.yes_ranges = dio48e_precious_ranges,
80 	.n_yes_ranges = ARRAY_SIZE(dio48e_precious_ranges),
81 };
82 
83 static const struct regmap_range pit_wr_ranges[] = {
84 	regmap_reg_range(0x0, 0x3),
85 };
86 static const struct regmap_range pit_rd_ranges[] = {
87 	regmap_reg_range(0x0, 0x2),
88 };
89 static const struct regmap_access_table pit_wr_table = {
90 	.yes_ranges = pit_wr_ranges,
91 	.n_yes_ranges = ARRAY_SIZE(pit_wr_ranges),
92 };
93 static const struct regmap_access_table pit_rd_table = {
94 	.yes_ranges = pit_rd_ranges,
95 	.n_yes_ranges = ARRAY_SIZE(pit_rd_ranges),
96 };
97 
98 /* only bit 3 on each respective Port C supports interrupts */
99 #define DIO48E_REGMAP_IRQ(_ppi)						\
100 	[19 + (_ppi) * 24] = {						\
101 		.mask = BIT(_ppi),					\
102 		.type = { .types_supported = IRQ_TYPE_EDGE_RISING },	\
103 	}
104 
105 static const struct regmap_irq dio48e_regmap_irqs[] = {
106 	DIO48E_REGMAP_IRQ(0), DIO48E_REGMAP_IRQ(1),
107 };
108 
109 /**
110  * struct dio48e_gpio - GPIO device private data structure
111  * @lock:	synchronization lock to prevent I/O race conditions
112  * @map:	Regmap for the device
113  * @regs:	virtual mapping for device registers
114  * @flags:	IRQ flags saved during locking
115  * @irq_mask:	Current IRQ mask state on the device
116  */
117 struct dio48e_gpio {
118 	raw_spinlock_t lock;
119 	struct regmap *map;
120 	void __iomem *regs;
121 	unsigned long flags;
122 	unsigned int irq_mask;
123 };
124 
125 static void dio48e_regmap_lock(void *lock_arg) __acquires(&dio48egpio->lock)
126 {
127 	struct dio48e_gpio *const dio48egpio = lock_arg;
128 	unsigned long flags;
129 
130 	raw_spin_lock_irqsave(&dio48egpio->lock, flags);
131 	dio48egpio->flags = flags;
132 }
133 
134 static void dio48e_regmap_unlock(void *lock_arg) __releases(&dio48egpio->lock)
135 {
136 	struct dio48e_gpio *const dio48egpio = lock_arg;
137 
138 	raw_spin_unlock_irqrestore(&dio48egpio->lock, dio48egpio->flags);
139 }
140 
141 static void pit_regmap_lock(void *lock_arg) __acquires(&dio48egpio->lock)
142 {
143 	struct dio48e_gpio *const dio48egpio = lock_arg;
144 	unsigned long flags;
145 
146 	raw_spin_lock_irqsave(&dio48egpio->lock, flags);
147 	dio48egpio->flags = flags;
148 
149 	iowrite8(0x00, dio48egpio->regs + DIO48E_ENABLE_COUNTER_TIMER_ADDRESSING);
150 }
151 
152 static void pit_regmap_unlock(void *lock_arg) __releases(&dio48egpio->lock)
153 {
154 	struct dio48e_gpio *const dio48egpio = lock_arg;
155 
156 	ioread8(dio48egpio->regs + DIO48E_DISABLE_COUNTER_TIMER_ADDRESSING);
157 
158 	raw_spin_unlock_irqrestore(&dio48egpio->lock, dio48egpio->flags);
159 }
160 
161 static int dio48e_handle_mask_sync(const int index,
162 				   const unsigned int mask_buf_def,
163 				   const unsigned int mask_buf,
164 				   void *const irq_drv_data)
165 {
166 	struct dio48e_gpio *const dio48egpio = irq_drv_data;
167 	const unsigned int prev_mask = dio48egpio->irq_mask;
168 	int err;
169 	unsigned int val;
170 
171 	/* exit early if no change since the previous mask */
172 	if (mask_buf == prev_mask)
173 		return 0;
174 
175 	/* remember the current mask for the next mask sync */
176 	dio48egpio->irq_mask = mask_buf;
177 
178 	/* if all previously masked, enable interrupts when unmasking */
179 	if (prev_mask == mask_buf_def) {
180 		err = regmap_write(dio48egpio->map, DIO48E_CLEAR_INTERRUPT, 0x00);
181 		if (err)
182 			return err;
183 		return regmap_write(dio48egpio->map, DIO48E_ENABLE_INTERRUPT, 0x00);
184 	}
185 
186 	/* if all are currently masked, disable interrupts */
187 	if (mask_buf == mask_buf_def)
188 		return regmap_read(dio48egpio->map, DIO48E_DISABLE_INTERRUPT, &val);
189 
190 	return 0;
191 }
192 
193 #define DIO48E_NGPIO 48
194 static const char *dio48e_names[DIO48E_NGPIO] = {
195 	"PPI Group 0 Port A 0", "PPI Group 0 Port A 1", "PPI Group 0 Port A 2",
196 	"PPI Group 0 Port A 3", "PPI Group 0 Port A 4", "PPI Group 0 Port A 5",
197 	"PPI Group 0 Port A 6", "PPI Group 0 Port A 7",	"PPI Group 0 Port B 0",
198 	"PPI Group 0 Port B 1", "PPI Group 0 Port B 2", "PPI Group 0 Port B 3",
199 	"PPI Group 0 Port B 4", "PPI Group 0 Port B 5", "PPI Group 0 Port B 6",
200 	"PPI Group 0 Port B 7", "PPI Group 0 Port C 0", "PPI Group 0 Port C 1",
201 	"PPI Group 0 Port C 2", "PPI Group 0 Port C 3", "PPI Group 0 Port C 4",
202 	"PPI Group 0 Port C 5", "PPI Group 0 Port C 6", "PPI Group 0 Port C 7",
203 	"PPI Group 1 Port A 0", "PPI Group 1 Port A 1", "PPI Group 1 Port A 2",
204 	"PPI Group 1 Port A 3", "PPI Group 1 Port A 4", "PPI Group 1 Port A 5",
205 	"PPI Group 1 Port A 6", "PPI Group 1 Port A 7",	"PPI Group 1 Port B 0",
206 	"PPI Group 1 Port B 1", "PPI Group 1 Port B 2", "PPI Group 1 Port B 3",
207 	"PPI Group 1 Port B 4", "PPI Group 1 Port B 5", "PPI Group 1 Port B 6",
208 	"PPI Group 1 Port B 7", "PPI Group 1 Port C 0", "PPI Group 1 Port C 1",
209 	"PPI Group 1 Port C 2", "PPI Group 1 Port C 3", "PPI Group 1 Port C 4",
210 	"PPI Group 1 Port C 5", "PPI Group 1 Port C 6", "PPI Group 1 Port C 7"
211 };
212 
213 static int dio48e_irq_init_hw(struct regmap *const map)
214 {
215 	unsigned int val;
216 
217 	/* Disable IRQ by default */
218 	return regmap_read(map, DIO48E_DISABLE_INTERRUPT, &val);
219 }
220 
221 static int dio48e_probe(struct device *dev, unsigned int id)
222 {
223 	const char *const name = dev_name(dev);
224 	struct i8255_regmap_config config = {};
225 	void __iomem *regs;
226 	struct regmap *map;
227 	struct regmap_config dio48e_regmap_config;
228 	struct regmap_config pit_regmap_config;
229 	struct i8254_regmap_config pit_config;
230 	int err;
231 	struct regmap_irq_chip *chip;
232 	struct dio48e_gpio *dio48egpio;
233 	struct regmap_irq_chip_data *chip_data;
234 
235 	if (!devm_request_region(dev, base[id], DIO48E_EXTENT, name)) {
236 		dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
237 			base[id], base[id] + DIO48E_EXTENT);
238 		return -EBUSY;
239 	}
240 
241 	dio48egpio = devm_kzalloc(dev, sizeof(*dio48egpio), GFP_KERNEL);
242 	if (!dio48egpio)
243 		return -ENOMEM;
244 
245 	regs = devm_ioport_map(dev, base[id], DIO48E_EXTENT);
246 	if (!regs)
247 		return -ENOMEM;
248 
249 	dio48egpio->regs = regs;
250 
251 	raw_spin_lock_init(&dio48egpio->lock);
252 
253 	dio48e_regmap_config = (struct regmap_config) {
254 		.reg_bits = 8,
255 		.reg_stride = 1,
256 		.val_bits = 8,
257 		.lock = dio48e_regmap_lock,
258 		.unlock = dio48e_regmap_unlock,
259 		.lock_arg = dio48egpio,
260 		.io_port = true,
261 		.wr_table = &dio48e_wr_table,
262 		.rd_table = &dio48e_rd_table,
263 		.volatile_table = &dio48e_volatile_table,
264 		.precious_table = &dio48e_precious_table,
265 		.cache_type = REGCACHE_FLAT,
266 	};
267 
268 	map = devm_regmap_init_mmio(dev, regs, &dio48e_regmap_config);
269 	if (IS_ERR(map))
270 		return dev_err_probe(dev, PTR_ERR(map),
271 				     "Unable to initialize register map\n");
272 
273 	dio48egpio->map = map;
274 
275 	pit_regmap_config = (struct regmap_config) {
276 		.name = "i8254",
277 		.reg_bits = 8,
278 		.reg_stride = 1,
279 		.val_bits = 8,
280 		.lock = pit_regmap_lock,
281 		.unlock = pit_regmap_unlock,
282 		.lock_arg = dio48egpio,
283 		.io_port = true,
284 		.wr_table = &pit_wr_table,
285 		.rd_table = &pit_rd_table,
286 	};
287 
288 	pit_config.map = devm_regmap_init_mmio(dev, regs, &pit_regmap_config);
289 	if (IS_ERR(pit_config.map))
290 		return dev_err_probe(dev, PTR_ERR(pit_config.map),
291 				     "Unable to initialize i8254 register map\n");
292 
293 	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
294 	if (!chip)
295 		return -ENOMEM;
296 
297 	chip->name = name;
298 	chip->mask_base = DIO48E_ENABLE_INTERRUPT;
299 	chip->ack_base = DIO48E_CLEAR_INTERRUPT;
300 	chip->no_status = true;
301 	chip->num_regs = 1;
302 	chip->irqs = dio48e_regmap_irqs;
303 	chip->num_irqs = ARRAY_SIZE(dio48e_regmap_irqs);
304 	chip->handle_mask_sync = dio48e_handle_mask_sync;
305 	chip->irq_drv_data = dio48egpio;
306 
307 	/* Initialize to prevent spurious interrupts before we're ready */
308 	err = dio48e_irq_init_hw(map);
309 	if (err)
310 		return err;
311 
312 	err = devm_regmap_add_irq_chip(dev, map, irq[id], 0, 0, chip, &chip_data);
313 	if (err)
314 		return dev_err_probe(dev, err, "IRQ registration failed\n");
315 
316 	pit_config.parent = dev;
317 
318 	err = devm_i8254_regmap_register(dev, &pit_config);
319 	if (err)
320 		return err;
321 
322 	config.parent = dev;
323 	config.map = map;
324 	config.num_ppi = DIO48E_NUM_PPI;
325 	config.names = dio48e_names;
326 	config.domain = regmap_irq_get_domain(chip_data);
327 
328 	return devm_i8255_regmap_register(dev, &config);
329 }
330 
331 static struct isa_driver dio48e_driver = {
332 	.probe = dio48e_probe,
333 	.driver = {
334 		.name = "104-dio-48e"
335 	},
336 };
337 module_isa_driver_with_irq(dio48e_driver, num_dio48e, num_irq);
338 
339 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
340 MODULE_DESCRIPTION("ACCES 104-DIO-48E GPIO driver");
341 MODULE_LICENSE("GPL v2");
342 MODULE_IMPORT_NS(I8254);
343