1 // SPDX-License-Identifier: GPL-2.0-only
2 
3 #include <linux/gpio/driver.h>
4 #include <linux/cpumask.h>
5 #include <linux/irq.h>
6 #include <linux/minmax.h>
7 #include <linux/mod_devicetable.h>
8 #include <linux/module.h>
9 #include <linux/platform_device.h>
10 #include <linux/property.h>
11 
12 /*
13  * Total register block size is 0x1C for one bank of four ports (A, B, C, D).
14  * An optional second bank, with ports E, F, G, and H, may be present, starting
15  * at register offset 0x1C.
16  */
17 
18 /*
19  * Pin select: (0) "normal", (1) "dedicate peripheral"
20  * Not used on RTL8380/RTL8390, peripheral selection is managed by control bits
21  * in the peripheral registers.
22  */
23 #define REALTEK_GPIO_REG_CNR		0x00
24 /* Clear bit (0) for input, set bit (1) for output */
25 #define REALTEK_GPIO_REG_DIR		0x08
26 #define REALTEK_GPIO_REG_DATA		0x0C
27 /* Read bit for IRQ status, write 1 to clear IRQ */
28 #define REALTEK_GPIO_REG_ISR		0x10
29 /* Two bits per GPIO in IMR registers */
30 #define REALTEK_GPIO_REG_IMR		0x14
31 #define REALTEK_GPIO_REG_IMR_AB		0x14
32 #define REALTEK_GPIO_REG_IMR_CD		0x18
33 #define REALTEK_GPIO_IMR_LINE_MASK	GENMASK(1, 0)
34 #define REALTEK_GPIO_IRQ_EDGE_FALLING	1
35 #define REALTEK_GPIO_IRQ_EDGE_RISING	2
36 #define REALTEK_GPIO_IRQ_EDGE_BOTH	3
37 
38 #define REALTEK_GPIO_MAX		32
39 #define REALTEK_GPIO_PORTS_PER_BANK	4
40 
41 /**
42  * realtek_gpio_ctrl - Realtek Otto GPIO driver data
43  *
44  * @gc: Associated gpio_chip instance
45  * @base: Base address of the register block for a GPIO bank
46  * @lock: Lock for accessing the IRQ registers and values
47  * @intr_mask: Mask for interrupts lines
48  * @intr_type: Interrupt type selection
49  * @bank_read: Read a bank setting as a single 32-bit value
50  * @bank_write: Write a bank setting as a single 32-bit value
51  * @imr_line_pos: Bit shift of an IRQ line's IMR value.
52  *
53  * The DIR, DATA, and ISR registers consist of four 8-bit port values, packed
54  * into a single 32-bit register. Use @bank_read (@bank_write) to get (assign)
55  * a value from (to) these registers. The IMR register consists of four 16-bit
56  * port values, packed into two 32-bit registers. Use @imr_line_pos to get the
57  * bit shift of the 2-bit field for a line's IMR settings. Shifts larger than
58  * 32 overflow into the second register.
59  *
60  * Because the interrupt mask register (IMR) combines the function of IRQ type
61  * selection and masking, two extra values are stored. @intr_mask is used to
62  * mask/unmask the interrupts for a GPIO line, and @intr_type is used to store
63  * the selected interrupt types. The logical AND of these values is written to
64  * IMR on changes.
65  */
66 struct realtek_gpio_ctrl {
67 	struct gpio_chip gc;
68 	void __iomem *base;
69 	void __iomem *cpumask_base;
70 	struct cpumask cpu_irq_maskable;
71 	raw_spinlock_t lock;
72 	u8 intr_mask[REALTEK_GPIO_MAX];
73 	u8 intr_type[REALTEK_GPIO_MAX];
74 	u32 (*bank_read)(void __iomem *reg);
75 	void (*bank_write)(void __iomem *reg, u32 value);
76 	unsigned int (*line_imr_pos)(unsigned int line);
77 };
78 
79 /* Expand with more flags as devices with other quirks are added */
80 enum realtek_gpio_flags {
81 	/*
82 	 * Allow disabling interrupts, for cases where the port order is
83 	 * unknown. This may result in a port mismatch between ISR and IMR.
84 	 * An interrupt would appear to come from a different line than the
85 	 * line the IRQ handler was assigned to, causing uncaught interrupts.
86 	 */
87 	GPIO_INTERRUPTS_DISABLED = BIT(0),
88 	/*
89 	 * Port order is reversed, meaning DCBA register layout for 1-bit
90 	 * fields, and [BA, DC] for 2-bit fields.
91 	 */
92 	GPIO_PORTS_REVERSED = BIT(1),
93 	/*
94 	 * Interrupts can be enabled per cpu. This requires a secondary IO
95 	 * range, where the per-cpu enable masks are located.
96 	 */
97 	GPIO_INTERRUPTS_PER_CPU = BIT(2),
98 };
99 
100 static struct realtek_gpio_ctrl *irq_data_to_ctrl(struct irq_data *data)
101 {
102 	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
103 
104 	return container_of(gc, struct realtek_gpio_ctrl, gc);
105 }
106 
107 /*
108  * Normal port order register access
109  *
110  * Port information is stored with the first port at offset 0, followed by the
111  * second, etc. Most registers store one bit per GPIO and use a u8 value per
112  * port. The two interrupt mask registers store two bits per GPIO, so use u16
113  * values.
114  */
115 static u32 realtek_gpio_bank_read_swapped(void __iomem *reg)
116 {
117 	return ioread32be(reg);
118 }
119 
120 static void realtek_gpio_bank_write_swapped(void __iomem *reg, u32 value)
121 {
122 	iowrite32be(value, reg);
123 }
124 
125 static unsigned int realtek_gpio_line_imr_pos_swapped(unsigned int line)
126 {
127 	unsigned int port_pin = line % 8;
128 	unsigned int port = line / 8;
129 
130 	return 2 * (8 * (port ^ 1) + port_pin);
131 }
132 
133 /*
134  * Reversed port order register access
135  *
136  * For registers with one bit per GPIO, all ports are stored as u8-s in one
137  * register in reversed order. The two interrupt mask registers store two bits
138  * per GPIO, so use u16 values. The first register contains ports 1 and 0, the
139  * second ports 3 and 2.
140  */
141 static u32 realtek_gpio_bank_read(void __iomem *reg)
142 {
143 	return ioread32(reg);
144 }
145 
146 static void realtek_gpio_bank_write(void __iomem *reg, u32 value)
147 {
148 	iowrite32(value, reg);
149 }
150 
151 static unsigned int realtek_gpio_line_imr_pos(unsigned int line)
152 {
153 	return 2 * line;
154 }
155 
156 static void realtek_gpio_clear_isr(struct realtek_gpio_ctrl *ctrl, u32 mask)
157 {
158 	ctrl->bank_write(ctrl->base + REALTEK_GPIO_REG_ISR, mask);
159 }
160 
161 static u32 realtek_gpio_read_isr(struct realtek_gpio_ctrl *ctrl)
162 {
163 	return ctrl->bank_read(ctrl->base + REALTEK_GPIO_REG_ISR);
164 }
165 
166 /* Set the rising and falling edge mask bits for a GPIO pin */
167 static void realtek_gpio_update_line_imr(struct realtek_gpio_ctrl *ctrl, unsigned int line)
168 {
169 	void __iomem *reg = ctrl->base + REALTEK_GPIO_REG_IMR;
170 	unsigned int line_shift = ctrl->line_imr_pos(line);
171 	unsigned int shift = line_shift % 32;
172 	u32 irq_type = ctrl->intr_type[line];
173 	u32 irq_mask = ctrl->intr_mask[line];
174 	u32 reg_val;
175 
176 	reg += 4 * (line_shift / 32);
177 	reg_val = ioread32(reg);
178 	reg_val &= ~(REALTEK_GPIO_IMR_LINE_MASK << shift);
179 	reg_val |= (irq_type & irq_mask & REALTEK_GPIO_IMR_LINE_MASK) << shift;
180 	iowrite32(reg_val, reg);
181 }
182 
183 static void realtek_gpio_irq_ack(struct irq_data *data)
184 {
185 	struct realtek_gpio_ctrl *ctrl = irq_data_to_ctrl(data);
186 	irq_hw_number_t line = irqd_to_hwirq(data);
187 
188 	realtek_gpio_clear_isr(ctrl, BIT(line));
189 }
190 
191 static void realtek_gpio_irq_unmask(struct irq_data *data)
192 {
193 	struct realtek_gpio_ctrl *ctrl = irq_data_to_ctrl(data);
194 	unsigned int line = irqd_to_hwirq(data);
195 	unsigned long flags;
196 
197 	gpiochip_enable_irq(&ctrl->gc, line);
198 
199 	raw_spin_lock_irqsave(&ctrl->lock, flags);
200 	ctrl->intr_mask[line] = REALTEK_GPIO_IMR_LINE_MASK;
201 	realtek_gpio_update_line_imr(ctrl, line);
202 	raw_spin_unlock_irqrestore(&ctrl->lock, flags);
203 }
204 
205 static void realtek_gpio_irq_mask(struct irq_data *data)
206 {
207 	struct realtek_gpio_ctrl *ctrl = irq_data_to_ctrl(data);
208 	unsigned int line = irqd_to_hwirq(data);
209 	unsigned long flags;
210 
211 	raw_spin_lock_irqsave(&ctrl->lock, flags);
212 	ctrl->intr_mask[line] = 0;
213 	realtek_gpio_update_line_imr(ctrl, line);
214 	raw_spin_unlock_irqrestore(&ctrl->lock, flags);
215 
216 	gpiochip_disable_irq(&ctrl->gc, line);
217 }
218 
219 static int realtek_gpio_irq_set_type(struct irq_data *data, unsigned int flow_type)
220 {
221 	struct realtek_gpio_ctrl *ctrl = irq_data_to_ctrl(data);
222 	unsigned int line = irqd_to_hwirq(data);
223 	unsigned long flags;
224 	u8 type;
225 
226 	switch (flow_type & IRQ_TYPE_SENSE_MASK) {
227 	case IRQ_TYPE_EDGE_FALLING:
228 		type = REALTEK_GPIO_IRQ_EDGE_FALLING;
229 		break;
230 	case IRQ_TYPE_EDGE_RISING:
231 		type = REALTEK_GPIO_IRQ_EDGE_RISING;
232 		break;
233 	case IRQ_TYPE_EDGE_BOTH:
234 		type = REALTEK_GPIO_IRQ_EDGE_BOTH;
235 		break;
236 	default:
237 		return -EINVAL;
238 	}
239 
240 	irq_set_handler_locked(data, handle_edge_irq);
241 
242 	raw_spin_lock_irqsave(&ctrl->lock, flags);
243 	ctrl->intr_type[line] = type;
244 	realtek_gpio_update_line_imr(ctrl, line);
245 	raw_spin_unlock_irqrestore(&ctrl->lock, flags);
246 
247 	return 0;
248 }
249 
250 static void realtek_gpio_irq_handler(struct irq_desc *desc)
251 {
252 	struct gpio_chip *gc = irq_desc_get_handler_data(desc);
253 	struct realtek_gpio_ctrl *ctrl = gpiochip_get_data(gc);
254 	struct irq_chip *irq_chip = irq_desc_get_chip(desc);
255 	unsigned long status;
256 	int offset;
257 
258 	chained_irq_enter(irq_chip, desc);
259 
260 	status = realtek_gpio_read_isr(ctrl);
261 	for_each_set_bit(offset, &status, gc->ngpio)
262 		generic_handle_domain_irq(gc->irq.domain, offset);
263 
264 	chained_irq_exit(irq_chip, desc);
265 }
266 
267 static inline void __iomem *realtek_gpio_irq_cpu_mask(struct realtek_gpio_ctrl *ctrl, int cpu)
268 {
269 	return ctrl->cpumask_base + REALTEK_GPIO_PORTS_PER_BANK * cpu;
270 }
271 
272 static int realtek_gpio_irq_set_affinity(struct irq_data *data,
273 	const struct cpumask *dest, bool force)
274 {
275 	struct realtek_gpio_ctrl *ctrl = irq_data_to_ctrl(data);
276 	unsigned int line = irqd_to_hwirq(data);
277 	void __iomem *irq_cpu_mask;
278 	unsigned long flags;
279 	int cpu;
280 	u32 v;
281 
282 	if (!ctrl->cpumask_base)
283 		return -ENXIO;
284 
285 	raw_spin_lock_irqsave(&ctrl->lock, flags);
286 
287 	for_each_cpu(cpu, &ctrl->cpu_irq_maskable) {
288 		irq_cpu_mask = realtek_gpio_irq_cpu_mask(ctrl, cpu);
289 		v = ctrl->bank_read(irq_cpu_mask);
290 
291 		if (cpumask_test_cpu(cpu, dest))
292 			v |= BIT(line);
293 		else
294 			v &= ~BIT(line);
295 
296 		ctrl->bank_write(irq_cpu_mask, v);
297 	}
298 
299 	raw_spin_unlock_irqrestore(&ctrl->lock, flags);
300 
301 	irq_data_update_effective_affinity(data, dest);
302 
303 	return 0;
304 }
305 
306 static int realtek_gpio_irq_init(struct gpio_chip *gc)
307 {
308 	struct realtek_gpio_ctrl *ctrl = gpiochip_get_data(gc);
309 	u32 mask_all = GENMASK(gc->ngpio - 1, 0);
310 	unsigned int line;
311 	int cpu;
312 
313 	for (line = 0; line < gc->ngpio; line++)
314 		realtek_gpio_update_line_imr(ctrl, line);
315 
316 	realtek_gpio_clear_isr(ctrl, mask_all);
317 
318 	for_each_cpu(cpu, &ctrl->cpu_irq_maskable)
319 		ctrl->bank_write(realtek_gpio_irq_cpu_mask(ctrl, cpu), mask_all);
320 
321 	return 0;
322 }
323 
324 static const struct irq_chip realtek_gpio_irq_chip = {
325 	.name = "realtek-otto-gpio",
326 	.irq_ack = realtek_gpio_irq_ack,
327 	.irq_mask = realtek_gpio_irq_mask,
328 	.irq_unmask = realtek_gpio_irq_unmask,
329 	.irq_set_type = realtek_gpio_irq_set_type,
330 	.irq_set_affinity = realtek_gpio_irq_set_affinity,
331 	.flags = IRQCHIP_IMMUTABLE,
332 	GPIOCHIP_IRQ_RESOURCE_HELPERS,
333 };
334 
335 static const struct of_device_id realtek_gpio_of_match[] = {
336 	{
337 		.compatible = "realtek,otto-gpio",
338 		.data = (void *)GPIO_INTERRUPTS_DISABLED,
339 	},
340 	{
341 		.compatible = "realtek,rtl8380-gpio",
342 	},
343 	{
344 		.compatible = "realtek,rtl8390-gpio",
345 	},
346 	{
347 		.compatible = "realtek,rtl9300-gpio",
348 		.data = (void *)(GPIO_PORTS_REVERSED | GPIO_INTERRUPTS_PER_CPU)
349 	},
350 	{
351 		.compatible = "realtek,rtl9310-gpio",
352 	},
353 	{}
354 };
355 MODULE_DEVICE_TABLE(of, realtek_gpio_of_match);
356 
357 static int realtek_gpio_probe(struct platform_device *pdev)
358 {
359 	struct device *dev = &pdev->dev;
360 	unsigned long bgpio_flags;
361 	unsigned int dev_flags;
362 	struct gpio_irq_chip *girq;
363 	struct realtek_gpio_ctrl *ctrl;
364 	struct resource *res;
365 	u32 ngpios;
366 	unsigned int nr_cpus;
367 	int cpu, err, irq;
368 
369 	ctrl = devm_kzalloc(dev, sizeof(*ctrl), GFP_KERNEL);
370 	if (!ctrl)
371 		return -ENOMEM;
372 
373 	dev_flags = (unsigned int) device_get_match_data(dev);
374 
375 	ngpios = REALTEK_GPIO_MAX;
376 	device_property_read_u32(dev, "ngpios", &ngpios);
377 
378 	if (ngpios > REALTEK_GPIO_MAX) {
379 		dev_err(&pdev->dev, "invalid ngpios (max. %d)\n",
380 			REALTEK_GPIO_MAX);
381 		return -EINVAL;
382 	}
383 
384 	ctrl->base = devm_platform_ioremap_resource(pdev, 0);
385 	if (IS_ERR(ctrl->base))
386 		return PTR_ERR(ctrl->base);
387 
388 	raw_spin_lock_init(&ctrl->lock);
389 
390 	if (dev_flags & GPIO_PORTS_REVERSED) {
391 		bgpio_flags = 0;
392 		ctrl->bank_read = realtek_gpio_bank_read;
393 		ctrl->bank_write = realtek_gpio_bank_write;
394 		ctrl->line_imr_pos = realtek_gpio_line_imr_pos;
395 	} else {
396 		bgpio_flags = BGPIOF_BIG_ENDIAN_BYTE_ORDER;
397 		ctrl->bank_read = realtek_gpio_bank_read_swapped;
398 		ctrl->bank_write = realtek_gpio_bank_write_swapped;
399 		ctrl->line_imr_pos = realtek_gpio_line_imr_pos_swapped;
400 	}
401 
402 	err = bgpio_init(&ctrl->gc, dev, 4,
403 		ctrl->base + REALTEK_GPIO_REG_DATA, NULL, NULL,
404 		ctrl->base + REALTEK_GPIO_REG_DIR, NULL,
405 		bgpio_flags);
406 	if (err) {
407 		dev_err(dev, "unable to init generic GPIO");
408 		return err;
409 	}
410 
411 	ctrl->gc.ngpio = ngpios;
412 	ctrl->gc.owner = THIS_MODULE;
413 
414 	irq = platform_get_irq_optional(pdev, 0);
415 	if (!(dev_flags & GPIO_INTERRUPTS_DISABLED) && irq > 0) {
416 		girq = &ctrl->gc.irq;
417 		gpio_irq_chip_set_chip(girq, &realtek_gpio_irq_chip);
418 		girq->default_type = IRQ_TYPE_NONE;
419 		girq->handler = handle_bad_irq;
420 		girq->parent_handler = realtek_gpio_irq_handler;
421 		girq->num_parents = 1;
422 		girq->parents = devm_kcalloc(dev, girq->num_parents,
423 					sizeof(*girq->parents),	GFP_KERNEL);
424 		if (!girq->parents)
425 			return -ENOMEM;
426 		girq->parents[0] = irq;
427 		girq->init_hw = realtek_gpio_irq_init;
428 	}
429 
430 	cpumask_clear(&ctrl->cpu_irq_maskable);
431 
432 	if ((dev_flags & GPIO_INTERRUPTS_PER_CPU) && irq > 0) {
433 		ctrl->cpumask_base = devm_platform_get_and_ioremap_resource(pdev, 1, &res);
434 		if (IS_ERR(ctrl->cpumask_base))
435 			return dev_err_probe(dev, PTR_ERR(ctrl->cpumask_base),
436 				"missing CPU IRQ mask registers");
437 
438 		nr_cpus = resource_size(res) / REALTEK_GPIO_PORTS_PER_BANK;
439 		nr_cpus = min(nr_cpus, num_present_cpus());
440 
441 		for (cpu = 0; cpu < nr_cpus; cpu++)
442 			cpumask_set_cpu(cpu, &ctrl->cpu_irq_maskable);
443 	}
444 
445 	return devm_gpiochip_add_data(dev, &ctrl->gc, ctrl);
446 }
447 
448 static struct platform_driver realtek_gpio_driver = {
449 	.driver = {
450 		.name = "realtek-otto-gpio",
451 		.of_match_table	= realtek_gpio_of_match,
452 	},
453 	.probe = realtek_gpio_probe,
454 };
455 module_platform_driver(realtek_gpio_driver);
456 
457 MODULE_DESCRIPTION("Realtek Otto GPIO support");
458 MODULE_AUTHOR("Sander Vanheule <sander@svanheule.net>");
459 MODULE_LICENSE("GPL v2");
460