1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2009-2011 Gabor Juhos <juhosg@openwrt.org>
4  * Copyright (C) 2013 John Crispin <blogic@openwrt.org>
5  */
6 
7 #include <linux/err.h>
8 #include <linux/gpio/driver.h>
9 #include <linux/interrupt.h>
10 #include <linux/io.h>
11 #include <linux/module.h>
12 #include <linux/platform_device.h>
13 #include <linux/spinlock.h>
14 
15 #define MTK_BANK_CNT	3
16 #define MTK_BANK_WIDTH	32
17 
18 #define GPIO_BANK_STRIDE	0x04
19 #define GPIO_REG_CTRL		0x00
20 #define GPIO_REG_POL		0x10
21 #define GPIO_REG_DATA		0x20
22 #define GPIO_REG_DSET		0x30
23 #define GPIO_REG_DCLR		0x40
24 #define GPIO_REG_REDGE		0x50
25 #define GPIO_REG_FEDGE		0x60
26 #define GPIO_REG_HLVL		0x70
27 #define GPIO_REG_LLVL		0x80
28 #define GPIO_REG_STAT		0x90
29 #define GPIO_REG_EDGE		0xA0
30 
31 struct mtk_gc {
32 	struct irq_chip irq_chip;
33 	struct gpio_chip chip;
34 	spinlock_t lock;
35 	int bank;
36 	u32 rising;
37 	u32 falling;
38 	u32 hlevel;
39 	u32 llevel;
40 };
41 
42 /**
43  * struct mtk - state container for
44  * data of the platform driver. It is 3
45  * separate gpio-chip each one with its
46  * own irq_chip.
47  * @dev: device instance
48  * @base: memory base address
49  * @gpio_irq: irq number from the device tree
50  * @gc_map: array of the gpio chips
51  */
52 struct mtk {
53 	struct device *dev;
54 	void __iomem *base;
55 	int gpio_irq;
56 	struct mtk_gc gc_map[MTK_BANK_CNT];
57 };
58 
59 static inline struct mtk_gc *
to_mediatek_gpio(struct gpio_chip * chip)60 to_mediatek_gpio(struct gpio_chip *chip)
61 {
62 	return container_of(chip, struct mtk_gc, chip);
63 }
64 
65 static inline void
mtk_gpio_w32(struct mtk_gc * rg,u32 offset,u32 val)66 mtk_gpio_w32(struct mtk_gc *rg, u32 offset, u32 val)
67 {
68 	struct gpio_chip *gc = &rg->chip;
69 	struct mtk *mtk = gpiochip_get_data(gc);
70 
71 	offset = (rg->bank * GPIO_BANK_STRIDE) + offset;
72 	gc->write_reg(mtk->base + offset, val);
73 }
74 
75 static inline u32
mtk_gpio_r32(struct mtk_gc * rg,u32 offset)76 mtk_gpio_r32(struct mtk_gc *rg, u32 offset)
77 {
78 	struct gpio_chip *gc = &rg->chip;
79 	struct mtk *mtk = gpiochip_get_data(gc);
80 
81 	offset = (rg->bank * GPIO_BANK_STRIDE) + offset;
82 	return gc->read_reg(mtk->base + offset);
83 }
84 
85 static irqreturn_t
mediatek_gpio_irq_handler(int irq,void * data)86 mediatek_gpio_irq_handler(int irq, void *data)
87 {
88 	struct gpio_chip *gc = data;
89 	struct mtk_gc *rg = to_mediatek_gpio(gc);
90 	irqreturn_t ret = IRQ_NONE;
91 	unsigned long pending;
92 	int bit;
93 
94 	pending = mtk_gpio_r32(rg, GPIO_REG_STAT);
95 
96 	for_each_set_bit(bit, &pending, MTK_BANK_WIDTH) {
97 		generic_handle_domain_irq(gc->irq.domain, bit);
98 		mtk_gpio_w32(rg, GPIO_REG_STAT, BIT(bit));
99 		ret |= IRQ_HANDLED;
100 	}
101 
102 	return ret;
103 }
104 
105 static void
mediatek_gpio_irq_unmask(struct irq_data * d)106 mediatek_gpio_irq_unmask(struct irq_data *d)
107 {
108 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
109 	struct mtk_gc *rg = to_mediatek_gpio(gc);
110 	int pin = d->hwirq;
111 	unsigned long flags;
112 	u32 rise, fall, high, low;
113 
114 	gpiochip_enable_irq(gc, d->hwirq);
115 
116 	spin_lock_irqsave(&rg->lock, flags);
117 	rise = mtk_gpio_r32(rg, GPIO_REG_REDGE);
118 	fall = mtk_gpio_r32(rg, GPIO_REG_FEDGE);
119 	high = mtk_gpio_r32(rg, GPIO_REG_HLVL);
120 	low = mtk_gpio_r32(rg, GPIO_REG_LLVL);
121 	mtk_gpio_w32(rg, GPIO_REG_REDGE, rise | (BIT(pin) & rg->rising));
122 	mtk_gpio_w32(rg, GPIO_REG_FEDGE, fall | (BIT(pin) & rg->falling));
123 	mtk_gpio_w32(rg, GPIO_REG_HLVL, high | (BIT(pin) & rg->hlevel));
124 	mtk_gpio_w32(rg, GPIO_REG_LLVL, low | (BIT(pin) & rg->llevel));
125 	spin_unlock_irqrestore(&rg->lock, flags);
126 }
127 
128 static void
mediatek_gpio_irq_mask(struct irq_data * d)129 mediatek_gpio_irq_mask(struct irq_data *d)
130 {
131 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
132 	struct mtk_gc *rg = to_mediatek_gpio(gc);
133 	int pin = d->hwirq;
134 	unsigned long flags;
135 	u32 rise, fall, high, low;
136 
137 	spin_lock_irqsave(&rg->lock, flags);
138 	rise = mtk_gpio_r32(rg, GPIO_REG_REDGE);
139 	fall = mtk_gpio_r32(rg, GPIO_REG_FEDGE);
140 	high = mtk_gpio_r32(rg, GPIO_REG_HLVL);
141 	low = mtk_gpio_r32(rg, GPIO_REG_LLVL);
142 	mtk_gpio_w32(rg, GPIO_REG_FEDGE, fall & ~BIT(pin));
143 	mtk_gpio_w32(rg, GPIO_REG_REDGE, rise & ~BIT(pin));
144 	mtk_gpio_w32(rg, GPIO_REG_HLVL, high & ~BIT(pin));
145 	mtk_gpio_w32(rg, GPIO_REG_LLVL, low & ~BIT(pin));
146 	spin_unlock_irqrestore(&rg->lock, flags);
147 
148 	gpiochip_disable_irq(gc, d->hwirq);
149 }
150 
151 static int
mediatek_gpio_irq_type(struct irq_data * d,unsigned int type)152 mediatek_gpio_irq_type(struct irq_data *d, unsigned int type)
153 {
154 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
155 	struct mtk_gc *rg = to_mediatek_gpio(gc);
156 	int pin = d->hwirq;
157 	u32 mask = BIT(pin);
158 
159 	if (type == IRQ_TYPE_PROBE) {
160 		if ((rg->rising | rg->falling |
161 		     rg->hlevel | rg->llevel) & mask)
162 			return 0;
163 
164 		type = IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING;
165 	}
166 
167 	rg->rising &= ~mask;
168 	rg->falling &= ~mask;
169 	rg->hlevel &= ~mask;
170 	rg->llevel &= ~mask;
171 
172 	switch (type & IRQ_TYPE_SENSE_MASK) {
173 	case IRQ_TYPE_EDGE_BOTH:
174 		rg->rising |= mask;
175 		rg->falling |= mask;
176 		break;
177 	case IRQ_TYPE_EDGE_RISING:
178 		rg->rising |= mask;
179 		break;
180 	case IRQ_TYPE_EDGE_FALLING:
181 		rg->falling |= mask;
182 		break;
183 	case IRQ_TYPE_LEVEL_HIGH:
184 		rg->hlevel |= mask;
185 		break;
186 	case IRQ_TYPE_LEVEL_LOW:
187 		rg->llevel |= mask;
188 		break;
189 	}
190 
191 	return 0;
192 }
193 
194 static int
mediatek_gpio_xlate(struct gpio_chip * chip,const struct of_phandle_args * spec,u32 * flags)195 mediatek_gpio_xlate(struct gpio_chip *chip,
196 		    const struct of_phandle_args *spec, u32 *flags)
197 {
198 	int gpio = spec->args[0];
199 	struct mtk_gc *rg = to_mediatek_gpio(chip);
200 
201 	if (rg->bank != gpio / MTK_BANK_WIDTH)
202 		return -EINVAL;
203 
204 	if (flags)
205 		*flags = spec->args[1];
206 
207 	return gpio % MTK_BANK_WIDTH;
208 }
209 
210 static const struct irq_chip mt7621_irq_chip = {
211 	.name		= "mt7621-gpio",
212 	.irq_mask_ack	= mediatek_gpio_irq_mask,
213 	.irq_mask	= mediatek_gpio_irq_mask,
214 	.irq_unmask	= mediatek_gpio_irq_unmask,
215 	.irq_set_type	= mediatek_gpio_irq_type,
216 	.flags		= IRQCHIP_IMMUTABLE,
217 	GPIOCHIP_IRQ_RESOURCE_HELPERS,
218 };
219 
220 static int
mediatek_gpio_bank_probe(struct device * dev,int bank)221 mediatek_gpio_bank_probe(struct device *dev, int bank)
222 {
223 	struct mtk *mtk = dev_get_drvdata(dev);
224 	struct mtk_gc *rg;
225 	void __iomem *dat, *set, *ctrl, *diro;
226 	int ret;
227 
228 	rg = &mtk->gc_map[bank];
229 	memset(rg, 0, sizeof(*rg));
230 
231 	spin_lock_init(&rg->lock);
232 	rg->bank = bank;
233 
234 	dat = mtk->base + GPIO_REG_DATA + (rg->bank * GPIO_BANK_STRIDE);
235 	set = mtk->base + GPIO_REG_DSET + (rg->bank * GPIO_BANK_STRIDE);
236 	ctrl = mtk->base + GPIO_REG_DCLR + (rg->bank * GPIO_BANK_STRIDE);
237 	diro = mtk->base + GPIO_REG_CTRL + (rg->bank * GPIO_BANK_STRIDE);
238 
239 	ret = bgpio_init(&rg->chip, dev, 4, dat, set, ctrl, diro, NULL,
240 			 BGPIOF_NO_SET_ON_INPUT);
241 	if (ret) {
242 		dev_err(dev, "bgpio_init() failed\n");
243 		return ret;
244 	}
245 
246 	rg->chip.of_gpio_n_cells = 2;
247 	rg->chip.of_xlate = mediatek_gpio_xlate;
248 	rg->chip.label = devm_kasprintf(dev, GFP_KERNEL, "%s-bank%d",
249 					dev_name(dev), bank);
250 	if (!rg->chip.label)
251 		return -ENOMEM;
252 
253 	rg->chip.offset = bank * MTK_BANK_WIDTH;
254 
255 	if (mtk->gpio_irq) {
256 		struct gpio_irq_chip *girq;
257 
258 		/*
259 		 * Directly request the irq here instead of passing
260 		 * a flow-handler because the irq is shared.
261 		 */
262 		ret = devm_request_irq(dev, mtk->gpio_irq,
263 				       mediatek_gpio_irq_handler, IRQF_SHARED,
264 				       rg->chip.label, &rg->chip);
265 
266 		if (ret) {
267 			dev_err(dev, "Error requesting IRQ %d: %d\n",
268 				mtk->gpio_irq, ret);
269 			return ret;
270 		}
271 
272 		girq = &rg->chip.irq;
273 		gpio_irq_chip_set_chip(girq, &mt7621_irq_chip);
274 		/* This will let us handle the parent IRQ in the driver */
275 		girq->parent_handler = NULL;
276 		girq->num_parents = 0;
277 		girq->parents = NULL;
278 		girq->default_type = IRQ_TYPE_NONE;
279 		girq->handler = handle_simple_irq;
280 	}
281 
282 	ret = devm_gpiochip_add_data(dev, &rg->chip, mtk);
283 	if (ret < 0) {
284 		dev_err(dev, "Could not register gpio %d, ret=%d\n",
285 			rg->chip.ngpio, ret);
286 		return ret;
287 	}
288 
289 	/* set polarity to low for all gpios */
290 	mtk_gpio_w32(rg, GPIO_REG_POL, 0);
291 
292 	dev_info(dev, "registering %d gpios\n", rg->chip.ngpio);
293 
294 	return 0;
295 }
296 
297 static int
mediatek_gpio_probe(struct platform_device * pdev)298 mediatek_gpio_probe(struct platform_device *pdev)
299 {
300 	struct device *dev = &pdev->dev;
301 	struct mtk *mtk;
302 	int i;
303 	int ret;
304 
305 	mtk = devm_kzalloc(dev, sizeof(*mtk), GFP_KERNEL);
306 	if (!mtk)
307 		return -ENOMEM;
308 
309 	mtk->base = devm_platform_ioremap_resource(pdev, 0);
310 	if (IS_ERR(mtk->base))
311 		return PTR_ERR(mtk->base);
312 
313 	mtk->gpio_irq = platform_get_irq(pdev, 0);
314 	if (mtk->gpio_irq < 0)
315 		return mtk->gpio_irq;
316 
317 	mtk->dev = dev;
318 	platform_set_drvdata(pdev, mtk);
319 
320 	for (i = 0; i < MTK_BANK_CNT; i++) {
321 		ret = mediatek_gpio_bank_probe(dev, i);
322 		if (ret)
323 			return ret;
324 	}
325 
326 	return 0;
327 }
328 
329 static const struct of_device_id mediatek_gpio_match[] = {
330 	{ .compatible = "mediatek,mt7621-gpio" },
331 	{},
332 };
333 MODULE_DEVICE_TABLE(of, mediatek_gpio_match);
334 
335 static struct platform_driver mediatek_gpio_driver = {
336 	.probe = mediatek_gpio_probe,
337 	.driver = {
338 		.name = "mt7621_gpio",
339 		.of_match_table = mediatek_gpio_match,
340 	},
341 };
342 
343 builtin_platform_driver(mediatek_gpio_driver);
344