1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * TQ-Systems TQMx86 PLD GPIO driver
4 *
5 * Based on vendor driver by:
6 * Vadim V.Vlasov <vvlasov@dev.rtsoft.ru>
7 */
8
9 #include <linux/bitmap.h>
10 #include <linux/bitops.h>
11 #include <linux/errno.h>
12 #include <linux/gpio/driver.h>
13 #include <linux/init.h>
14 #include <linux/interrupt.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/platform_device.h>
18 #include <linux/pm_runtime.h>
19 #include <linux/seq_file.h>
20 #include <linux/slab.h>
21
22 #define TQMX86_NGPIO 8
23 #define TQMX86_NGPO 4 /* 0-3 - output */
24 #define TQMX86_NGPI 4 /* 4-7 - input */
25 #define TQMX86_DIR_INPUT_MASK 0xf0 /* 0-3 - output, 4-7 - input */
26
27 #define TQMX86_GPIODD 0 /* GPIO Data Direction Register */
28 #define TQMX86_GPIOD 1 /* GPIO Data Register */
29 #define TQMX86_GPIIC 3 /* GPI Interrupt Configuration Register */
30 #define TQMX86_GPIIS 4 /* GPI Interrupt Status Register */
31
32 #define TQMX86_GPII_NONE 0
33 #define TQMX86_GPII_FALLING BIT(0)
34 #define TQMX86_GPII_RISING BIT(1)
35 /* Stored in irq_type as a trigger type, but not actually valid as a register
36 * value, so the name doesn't use "GPII"
37 */
38 #define TQMX86_INT_BOTH (BIT(0) | BIT(1))
39 #define TQMX86_GPII_MASK (BIT(0) | BIT(1))
40 #define TQMX86_GPII_BITS 2
41 /* Stored in irq_type with GPII bits */
42 #define TQMX86_INT_UNMASKED BIT(2)
43
44 struct tqmx86_gpio_data {
45 struct gpio_chip chip;
46 void __iomem *io_base;
47 int irq;
48 /* Lock must be held for accessing output and irq_type fields */
49 raw_spinlock_t spinlock;
50 DECLARE_BITMAP(output, TQMX86_NGPIO);
51 u8 irq_type[TQMX86_NGPI];
52 };
53
tqmx86_gpio_read(struct tqmx86_gpio_data * gd,unsigned int reg)54 static u8 tqmx86_gpio_read(struct tqmx86_gpio_data *gd, unsigned int reg)
55 {
56 return ioread8(gd->io_base + reg);
57 }
58
tqmx86_gpio_write(struct tqmx86_gpio_data * gd,u8 val,unsigned int reg)59 static void tqmx86_gpio_write(struct tqmx86_gpio_data *gd, u8 val,
60 unsigned int reg)
61 {
62 iowrite8(val, gd->io_base + reg);
63 }
64
tqmx86_gpio_get(struct gpio_chip * chip,unsigned int offset)65 static int tqmx86_gpio_get(struct gpio_chip *chip, unsigned int offset)
66 {
67 struct tqmx86_gpio_data *gpio = gpiochip_get_data(chip);
68
69 return !!(tqmx86_gpio_read(gpio, TQMX86_GPIOD) & BIT(offset));
70 }
71
tqmx86_gpio_set(struct gpio_chip * chip,unsigned int offset,int value)72 static void tqmx86_gpio_set(struct gpio_chip *chip, unsigned int offset,
73 int value)
74 {
75 struct tqmx86_gpio_data *gpio = gpiochip_get_data(chip);
76 unsigned long flags;
77
78 raw_spin_lock_irqsave(&gpio->spinlock, flags);
79 __assign_bit(offset, gpio->output, value);
80 tqmx86_gpio_write(gpio, bitmap_get_value8(gpio->output, 0), TQMX86_GPIOD);
81 raw_spin_unlock_irqrestore(&gpio->spinlock, flags);
82 }
83
tqmx86_gpio_direction_input(struct gpio_chip * chip,unsigned int offset)84 static int tqmx86_gpio_direction_input(struct gpio_chip *chip,
85 unsigned int offset)
86 {
87 /* Direction cannot be changed. Validate is an input. */
88 if (BIT(offset) & TQMX86_DIR_INPUT_MASK)
89 return 0;
90 else
91 return -EINVAL;
92 }
93
tqmx86_gpio_direction_output(struct gpio_chip * chip,unsigned int offset,int value)94 static int tqmx86_gpio_direction_output(struct gpio_chip *chip,
95 unsigned int offset,
96 int value)
97 {
98 /* Direction cannot be changed, validate is an output */
99 if (BIT(offset) & TQMX86_DIR_INPUT_MASK)
100 return -EINVAL;
101
102 tqmx86_gpio_set(chip, offset, value);
103 return 0;
104 }
105
tqmx86_gpio_get_direction(struct gpio_chip * chip,unsigned int offset)106 static int tqmx86_gpio_get_direction(struct gpio_chip *chip,
107 unsigned int offset)
108 {
109 if (TQMX86_DIR_INPUT_MASK & BIT(offset))
110 return GPIO_LINE_DIRECTION_IN;
111
112 return GPIO_LINE_DIRECTION_OUT;
113 }
114
tqmx86_gpio_irq_config(struct tqmx86_gpio_data * gpio,int offset)115 static void tqmx86_gpio_irq_config(struct tqmx86_gpio_data *gpio, int offset)
116 __must_hold(&gpio->spinlock)
117 {
118 u8 type = TQMX86_GPII_NONE, gpiic;
119
120 if (gpio->irq_type[offset] & TQMX86_INT_UNMASKED) {
121 type = gpio->irq_type[offset] & TQMX86_GPII_MASK;
122
123 if (type == TQMX86_INT_BOTH)
124 type = tqmx86_gpio_get(&gpio->chip, offset + TQMX86_NGPO)
125 ? TQMX86_GPII_FALLING
126 : TQMX86_GPII_RISING;
127 }
128
129 gpiic = tqmx86_gpio_read(gpio, TQMX86_GPIIC);
130 gpiic &= ~(TQMX86_GPII_MASK << (offset * TQMX86_GPII_BITS));
131 gpiic |= type << (offset * TQMX86_GPII_BITS);
132 tqmx86_gpio_write(gpio, gpiic, TQMX86_GPIIC);
133 }
134
tqmx86_gpio_irq_mask(struct irq_data * data)135 static void tqmx86_gpio_irq_mask(struct irq_data *data)
136 {
137 unsigned int offset = (data->hwirq - TQMX86_NGPO);
138 struct tqmx86_gpio_data *gpio = gpiochip_get_data(
139 irq_data_get_irq_chip_data(data));
140 unsigned long flags;
141
142 raw_spin_lock_irqsave(&gpio->spinlock, flags);
143 gpio->irq_type[offset] &= ~TQMX86_INT_UNMASKED;
144 tqmx86_gpio_irq_config(gpio, offset);
145 raw_spin_unlock_irqrestore(&gpio->spinlock, flags);
146
147 gpiochip_disable_irq(&gpio->chip, irqd_to_hwirq(data));
148 }
149
tqmx86_gpio_irq_unmask(struct irq_data * data)150 static void tqmx86_gpio_irq_unmask(struct irq_data *data)
151 {
152 unsigned int offset = (data->hwirq - TQMX86_NGPO);
153 struct tqmx86_gpio_data *gpio = gpiochip_get_data(
154 irq_data_get_irq_chip_data(data));
155 unsigned long flags;
156
157 gpiochip_enable_irq(&gpio->chip, irqd_to_hwirq(data));
158
159 raw_spin_lock_irqsave(&gpio->spinlock, flags);
160 gpio->irq_type[offset] |= TQMX86_INT_UNMASKED;
161 tqmx86_gpio_irq_config(gpio, offset);
162 raw_spin_unlock_irqrestore(&gpio->spinlock, flags);
163 }
164
tqmx86_gpio_irq_set_type(struct irq_data * data,unsigned int type)165 static int tqmx86_gpio_irq_set_type(struct irq_data *data, unsigned int type)
166 {
167 struct tqmx86_gpio_data *gpio = gpiochip_get_data(
168 irq_data_get_irq_chip_data(data));
169 unsigned int offset = (data->hwirq - TQMX86_NGPO);
170 unsigned int edge_type = type & IRQF_TRIGGER_MASK;
171 unsigned long flags;
172 u8 new_type;
173
174 switch (edge_type) {
175 case IRQ_TYPE_EDGE_RISING:
176 new_type = TQMX86_GPII_RISING;
177 break;
178 case IRQ_TYPE_EDGE_FALLING:
179 new_type = TQMX86_GPII_FALLING;
180 break;
181 case IRQ_TYPE_EDGE_BOTH:
182 new_type = TQMX86_INT_BOTH;
183 break;
184 default:
185 return -EINVAL; /* not supported */
186 }
187
188 raw_spin_lock_irqsave(&gpio->spinlock, flags);
189 gpio->irq_type[offset] &= ~TQMX86_GPII_MASK;
190 gpio->irq_type[offset] |= new_type;
191 tqmx86_gpio_irq_config(gpio, offset);
192 raw_spin_unlock_irqrestore(&gpio->spinlock, flags);
193
194 return 0;
195 }
196
tqmx86_gpio_irq_handler(struct irq_desc * desc)197 static void tqmx86_gpio_irq_handler(struct irq_desc *desc)
198 {
199 struct gpio_chip *chip = irq_desc_get_handler_data(desc);
200 struct tqmx86_gpio_data *gpio = gpiochip_get_data(chip);
201 struct irq_chip *irq_chip = irq_desc_get_chip(desc);
202 unsigned long irq_bits, flags;
203 int i;
204 u8 irq_status;
205
206 chained_irq_enter(irq_chip, desc);
207
208 irq_status = tqmx86_gpio_read(gpio, TQMX86_GPIIS);
209 tqmx86_gpio_write(gpio, irq_status, TQMX86_GPIIS);
210
211 irq_bits = irq_status;
212
213 raw_spin_lock_irqsave(&gpio->spinlock, flags);
214 for_each_set_bit(i, &irq_bits, TQMX86_NGPI) {
215 /*
216 * Edge-both triggers are implemented by flipping the edge
217 * trigger after each interrupt, as the controller only supports
218 * either rising or falling edge triggers, but not both.
219 *
220 * Internally, the TQMx86 GPIO controller has separate status
221 * registers for rising and falling edge interrupts. GPIIC
222 * configures which bits from which register are visible in the
223 * interrupt status register GPIIS and defines what triggers the
224 * parent IRQ line. Writing to GPIIS always clears both rising
225 * and falling interrupt flags internally, regardless of the
226 * currently configured trigger.
227 *
228 * In consequence, we can cleanly implement the edge-both
229 * trigger in software by first clearing the interrupt and then
230 * setting the new trigger based on the current GPIO input in
231 * tqmx86_gpio_irq_config() - even if an edge arrives between
232 * reading the input and setting the trigger, we will have a new
233 * interrupt pending.
234 */
235 if ((gpio->irq_type[i] & TQMX86_GPII_MASK) == TQMX86_INT_BOTH)
236 tqmx86_gpio_irq_config(gpio, i);
237 }
238 raw_spin_unlock_irqrestore(&gpio->spinlock, flags);
239
240 for_each_set_bit(i, &irq_bits, TQMX86_NGPI)
241 generic_handle_domain_irq(gpio->chip.irq.domain,
242 i + TQMX86_NGPO);
243
244 chained_irq_exit(irq_chip, desc);
245 }
246
247 /* Minimal runtime PM is needed by the IRQ subsystem */
tqmx86_gpio_runtime_suspend(struct device * dev)248 static int __maybe_unused tqmx86_gpio_runtime_suspend(struct device *dev)
249 {
250 return 0;
251 }
252
tqmx86_gpio_runtime_resume(struct device * dev)253 static int __maybe_unused tqmx86_gpio_runtime_resume(struct device *dev)
254 {
255 return 0;
256 }
257
258 static const struct dev_pm_ops tqmx86_gpio_dev_pm_ops = {
259 SET_RUNTIME_PM_OPS(tqmx86_gpio_runtime_suspend,
260 tqmx86_gpio_runtime_resume, NULL)
261 };
262
tqmx86_init_irq_valid_mask(struct gpio_chip * chip,unsigned long * valid_mask,unsigned int ngpios)263 static void tqmx86_init_irq_valid_mask(struct gpio_chip *chip,
264 unsigned long *valid_mask,
265 unsigned int ngpios)
266 {
267 /* Only GPIOs 4-7 are valid for interrupts. Clear the others */
268 clear_bit(0, valid_mask);
269 clear_bit(1, valid_mask);
270 clear_bit(2, valid_mask);
271 clear_bit(3, valid_mask);
272 }
273
tqmx86_gpio_irq_print_chip(struct irq_data * d,struct seq_file * p)274 static void tqmx86_gpio_irq_print_chip(struct irq_data *d, struct seq_file *p)
275 {
276 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
277
278 seq_printf(p, gc->label);
279 }
280
281 static const struct irq_chip tqmx86_gpio_irq_chip = {
282 .irq_mask = tqmx86_gpio_irq_mask,
283 .irq_unmask = tqmx86_gpio_irq_unmask,
284 .irq_set_type = tqmx86_gpio_irq_set_type,
285 .irq_print_chip = tqmx86_gpio_irq_print_chip,
286 .flags = IRQCHIP_IMMUTABLE,
287 GPIOCHIP_IRQ_RESOURCE_HELPERS,
288 };
289
tqmx86_gpio_probe(struct platform_device * pdev)290 static int tqmx86_gpio_probe(struct platform_device *pdev)
291 {
292 struct device *dev = &pdev->dev;
293 struct tqmx86_gpio_data *gpio;
294 struct gpio_chip *chip;
295 struct gpio_irq_chip *girq;
296 void __iomem *io_base;
297 struct resource *res;
298 int ret, irq;
299
300 irq = platform_get_irq_optional(pdev, 0);
301 if (irq < 0 && irq != -ENXIO)
302 return irq;
303
304 res = platform_get_resource(pdev, IORESOURCE_IO, 0);
305 if (!res) {
306 dev_err(&pdev->dev, "Cannot get I/O\n");
307 return -ENODEV;
308 }
309
310 io_base = devm_ioport_map(&pdev->dev, res->start, resource_size(res));
311 if (!io_base)
312 return -ENOMEM;
313
314 gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL);
315 if (!gpio)
316 return -ENOMEM;
317
318 raw_spin_lock_init(&gpio->spinlock);
319 gpio->io_base = io_base;
320
321 tqmx86_gpio_write(gpio, (u8)~TQMX86_DIR_INPUT_MASK, TQMX86_GPIODD);
322
323 /*
324 * Reading the previous output state is not possible with TQMx86 hardware.
325 * Initialize all outputs to 0 to have a defined state that matches the
326 * shadow register.
327 */
328 tqmx86_gpio_write(gpio, 0, TQMX86_GPIOD);
329
330 chip = &gpio->chip;
331 chip->label = "gpio-tqmx86";
332 chip->owner = THIS_MODULE;
333 chip->can_sleep = false;
334 chip->base = -1;
335 chip->direction_input = tqmx86_gpio_direction_input;
336 chip->direction_output = tqmx86_gpio_direction_output;
337 chip->get_direction = tqmx86_gpio_get_direction;
338 chip->get = tqmx86_gpio_get;
339 chip->set = tqmx86_gpio_set;
340 chip->ngpio = TQMX86_NGPIO;
341 chip->parent = pdev->dev.parent;
342
343 pm_runtime_enable(&pdev->dev);
344
345 if (irq > 0) {
346 u8 irq_status;
347
348 /* Mask all interrupts */
349 tqmx86_gpio_write(gpio, 0, TQMX86_GPIIC);
350
351 /* Clear all pending interrupts */
352 irq_status = tqmx86_gpio_read(gpio, TQMX86_GPIIS);
353 tqmx86_gpio_write(gpio, irq_status, TQMX86_GPIIS);
354
355 girq = &chip->irq;
356 gpio_irq_chip_set_chip(girq, &tqmx86_gpio_irq_chip);
357 girq->parent_handler = tqmx86_gpio_irq_handler;
358 girq->num_parents = 1;
359 girq->parents = devm_kcalloc(&pdev->dev, 1,
360 sizeof(*girq->parents),
361 GFP_KERNEL);
362 if (!girq->parents) {
363 ret = -ENOMEM;
364 goto out_pm_dis;
365 }
366 girq->parents[0] = irq;
367 girq->default_type = IRQ_TYPE_NONE;
368 girq->handler = handle_simple_irq;
369 girq->init_valid_mask = tqmx86_init_irq_valid_mask;
370
371 irq_domain_set_pm_device(girq->domain, dev);
372 }
373
374 ret = devm_gpiochip_add_data(dev, chip, gpio);
375 if (ret) {
376 dev_err(dev, "Could not register GPIO chip\n");
377 goto out_pm_dis;
378 }
379
380 dev_info(dev, "GPIO functionality initialized with %d pins\n",
381 chip->ngpio);
382
383 return 0;
384
385 out_pm_dis:
386 pm_runtime_disable(&pdev->dev);
387
388 return ret;
389 }
390
391 static struct platform_driver tqmx86_gpio_driver = {
392 .driver = {
393 .name = "tqmx86-gpio",
394 .pm = &tqmx86_gpio_dev_pm_ops,
395 },
396 .probe = tqmx86_gpio_probe,
397 };
398
399 module_platform_driver(tqmx86_gpio_driver);
400
401 MODULE_DESCRIPTION("TQMx86 PLD GPIO Driver");
402 MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
403 MODULE_LICENSE("GPL");
404 MODULE_ALIAS("platform:tqmx86-gpio");
405