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/bitops.h>
10#include <linux/errno.h>
11#include <linux/gpio/driver.h>
12#include <linux/init.h>
13#include <linux/interrupt.h>
14#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/platform_device.h>
17#include <linux/pm_runtime.h>
18#include <linux/slab.h>
19
20#define TQMX86_NGPIO 8
21#define TQMX86_NGPO 4 /* 0-3 - output */
22#define TQMX86_NGPI 4 /* 4-7 - input */
23#define TQMX86_DIR_INPUT_MASK 0xf0 /* 0-3 - output, 4-7 - input */
24
25#define TQMX86_GPIODD 0 /* GPIO Data Direction Register */
26#define TQMX86_GPIOD 1 /* GPIO Data Register */
27#define TQMX86_GPIIC 3 /* GPI Interrupt Configuration Register */
28#define TQMX86_GPIIS 4 /* GPI Interrupt Status Register */
29
30#define TQMX86_GPII_FALLING BIT(0)
31#define TQMX86_GPII_RISING BIT(1)
32#define TQMX86_GPII_MASK (BIT(0) | BIT(1))
33#define TQMX86_GPII_BITS 2
34
35struct tqmx86_gpio_data {
36 struct gpio_chip chip;
37 struct irq_chip irq_chip;
38 void __iomem *io_base;
39 int irq;
40 raw_spinlock_t spinlock;
41 u8 irq_type[TQMX86_NGPI];
42};
43
44static u8 tqmx86_gpio_read(struct tqmx86_gpio_data *gd, unsigned int reg)
45{
46 return ioread8(gd->io_base + reg);
47}
48
49static void tqmx86_gpio_write(struct tqmx86_gpio_data *gd, u8 val,
50 unsigned int reg)
51{
52 iowrite8(val, gd->io_base + reg);
53}
54
55static int tqmx86_gpio_get(struct gpio_chip *chip, unsigned int offset)
56{
57 struct tqmx86_gpio_data *gpio = gpiochip_get_data(chip);
58
59 return !!(tqmx86_gpio_read(gpio, TQMX86_GPIOD) & BIT(offset));
60}
61
62static void tqmx86_gpio_set(struct gpio_chip *chip, unsigned int offset,
63 int value)
64{
65 struct tqmx86_gpio_data *gpio = gpiochip_get_data(chip);
66 unsigned long flags;
67 u8 val;
68
69 raw_spin_lock_irqsave(&gpio->spinlock, flags);
70 val = tqmx86_gpio_read(gpio, TQMX86_GPIOD);
71 if (value)
72 val |= BIT(offset);
73 else
74 val &= ~BIT(offset);
75 tqmx86_gpio_write(gpio, val, TQMX86_GPIOD);
76 raw_spin_unlock_irqrestore(&gpio->spinlock, flags);
77}
78
79static int tqmx86_gpio_direction_input(struct gpio_chip *chip,
80 unsigned int offset)
81{
82 /* Direction cannot be changed. Validate is an input. */
83 if (BIT(offset) & TQMX86_DIR_INPUT_MASK)
84 return 0;
85 else
86 return -EINVAL;
87}
88
89static int tqmx86_gpio_direction_output(struct gpio_chip *chip,
90 unsigned int offset,
91 int value)
92{
93 /* Direction cannot be changed, validate is an output */
94 if (BIT(offset) & TQMX86_DIR_INPUT_MASK)
95 return -EINVAL;
96
97 tqmx86_gpio_set(chip, offset, value);
98 return 0;
99}
100
101static int tqmx86_gpio_get_direction(struct gpio_chip *chip,
102 unsigned int offset)
103{
104 return !!(TQMX86_DIR_INPUT_MASK & BIT(offset));
105}
106
107static void tqmx86_gpio_irq_mask(struct irq_data *data)
108{
109 unsigned int offset = (data->hwirq - TQMX86_NGPO);
110 struct tqmx86_gpio_data *gpio = gpiochip_get_data(
111 irq_data_get_irq_chip_data(data));
112 unsigned long flags;
113 u8 gpiic, mask;
114
115 mask = TQMX86_GPII_MASK << (offset * TQMX86_GPII_BITS);
116
117 raw_spin_lock_irqsave(&gpio->spinlock, flags);
118 gpiic = tqmx86_gpio_read(gpio, TQMX86_GPIIC);
119 gpiic &= ~mask;
120 tqmx86_gpio_write(gpio, gpiic, TQMX86_GPIIC);
121 raw_spin_unlock_irqrestore(&gpio->spinlock, flags);
122}
123
124static void tqmx86_gpio_irq_unmask(struct irq_data *data)
125{
126 unsigned int offset = (data->hwirq - TQMX86_NGPO);
127 struct tqmx86_gpio_data *gpio = gpiochip_get_data(
128 irq_data_get_irq_chip_data(data));
129 unsigned long flags;
130 u8 gpiic, mask;
131
132 mask = TQMX86_GPII_MASK << (offset * TQMX86_GPII_BITS);
133
134 raw_spin_lock_irqsave(&gpio->spinlock, flags);
135 gpiic = tqmx86_gpio_read(gpio, TQMX86_GPIIC);
136 gpiic &= ~mask;
137 gpiic |= gpio->irq_type[offset] << (offset * TQMX86_GPII_BITS);
138 tqmx86_gpio_write(gpio, gpiic, TQMX86_GPIIC);
139 raw_spin_unlock_irqrestore(&gpio->spinlock, flags);
140}
141
142static int tqmx86_gpio_irq_set_type(struct irq_data *data, unsigned int type)
143{
144 struct tqmx86_gpio_data *gpio = gpiochip_get_data(
145 irq_data_get_irq_chip_data(data));
146 unsigned int offset = (data->hwirq - TQMX86_NGPO);
147 unsigned int edge_type = type & IRQF_TRIGGER_MASK;
148 unsigned long flags;
149 u8 new_type, gpiic;
150
151 switch (edge_type) {
152 case IRQ_TYPE_EDGE_RISING:
153 new_type = TQMX86_GPII_RISING;
154 break;
155 case IRQ_TYPE_EDGE_FALLING:
156 new_type = TQMX86_GPII_FALLING;
157 break;
158 case IRQ_TYPE_EDGE_BOTH:
159 new_type = TQMX86_GPII_FALLING | TQMX86_GPII_RISING;
160 break;
161 default:
162 return -EINVAL; /* not supported */
163 }
164
165 gpio->irq_type[offset] = new_type;
166
167 raw_spin_lock_irqsave(&gpio->spinlock, flags);
168 gpiic = tqmx86_gpio_read(gpio, TQMX86_GPIIC);
169 gpiic &= ~((TQMX86_GPII_MASK) << (offset * TQMX86_GPII_BITS));
170 gpiic |= new_type << (offset * TQMX86_GPII_BITS);
171 tqmx86_gpio_write(gpio, gpiic, TQMX86_GPIIC);
172 raw_spin_unlock_irqrestore(&gpio->spinlock, flags);
173
174 return 0;
175}
176
177static void tqmx86_gpio_irq_handler(struct irq_desc *desc)
178{
179 struct gpio_chip *chip = irq_desc_get_handler_data(desc);
180 struct tqmx86_gpio_data *gpio = gpiochip_get_data(chip);
181 struct irq_chip *irq_chip = irq_desc_get_chip(desc);
182 unsigned long irq_bits;
183 int i = 0, child_irq;
184 u8 irq_status;
185
186 chained_irq_enter(irq_chip, desc);
187
188 irq_status = tqmx86_gpio_read(gpio, TQMX86_GPIIS);
189 tqmx86_gpio_write(gpio, irq_status, TQMX86_GPIIS);
190
191 irq_bits = irq_status;
192 for_each_set_bit(i, &irq_bits, TQMX86_NGPI) {
193 child_irq = irq_find_mapping(gpio->chip.irq.domain,
194 i + TQMX86_NGPO);
195 generic_handle_irq(child_irq);
196 }
197
198 chained_irq_exit(irq_chip, desc);
199}
200
201/* Minimal runtime PM is needed by the IRQ subsystem */
202static int __maybe_unused tqmx86_gpio_runtime_suspend(struct device *dev)
203{
204 return 0;
205}
206
207static int __maybe_unused tqmx86_gpio_runtime_resume(struct device *dev)
208{
209 return 0;
210}
211
212static const struct dev_pm_ops tqmx86_gpio_dev_pm_ops = {
213 SET_RUNTIME_PM_OPS(tqmx86_gpio_runtime_suspend,
214 tqmx86_gpio_runtime_resume, NULL)
215};
216
217static int tqmx86_gpio_probe(struct platform_device *pdev)
218{
219 struct device *dev = &pdev->dev;
220 struct tqmx86_gpio_data *gpio;
221 struct gpio_chip *chip;
222 void __iomem *io_base;
223 struct resource *res;
224 int ret, irq;
225
226 irq = platform_get_irq(pdev, 0);
227 if (irq < 0)
228 return irq;
229
230 res = platform_get_resource(pdev, IORESOURCE_IO, 0);
231 if (!res) {
232 dev_err(&pdev->dev, "Cannot get I/O\n");
233 return -ENODEV;
234 }
235
236 io_base = devm_ioport_map(&pdev->dev, res->start, resource_size(res));
237 if (!io_base)
238 return -ENOMEM;
239
240 gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL);
241 if (!gpio)
242 return -ENOMEM;
243
244 raw_spin_lock_init(&gpio->spinlock);
245 gpio->io_base = io_base;
246
247 tqmx86_gpio_write(gpio, (u8)~TQMX86_DIR_INPUT_MASK, TQMX86_GPIODD);
248
249 platform_set_drvdata(pdev, gpio);
250
251 chip = &gpio->chip;
252 chip->label = "gpio-tqmx86";
253 chip->owner = THIS_MODULE;
254 chip->can_sleep = false;
255 chip->base = -1;
256 chip->direction_input = tqmx86_gpio_direction_input;
257 chip->direction_output = tqmx86_gpio_direction_output;
258 chip->get_direction = tqmx86_gpio_get_direction;
259 chip->get = tqmx86_gpio_get;
260 chip->set = tqmx86_gpio_set;
261 chip->ngpio = TQMX86_NGPIO;
262 chip->irq.need_valid_mask = true;
263 chip->parent = pdev->dev.parent;
264
265 pm_runtime_enable(&pdev->dev);
266
267 ret = devm_gpiochip_add_data(dev, chip, gpio);
268 if (ret) {
269 dev_err(dev, "Could not register GPIO chip\n");
270 goto out_pm_dis;
271 }
272
273 if (irq) {
274 struct irq_chip *irq_chip = &gpio->irq_chip;
275 u8 irq_status;
276
277 irq_chip->name = chip->label;
278 irq_chip->parent_device = &pdev->dev;
279 irq_chip->irq_mask = tqmx86_gpio_irq_mask;
280 irq_chip->irq_unmask = tqmx86_gpio_irq_unmask;
281 irq_chip->irq_set_type = tqmx86_gpio_irq_set_type;
282
283 /* Mask all interrupts */
284 tqmx86_gpio_write(gpio, 0, TQMX86_GPIIC);
285
286 /* Clear all pending interrupts */
287 irq_status = tqmx86_gpio_read(gpio, TQMX86_GPIIS);
288 tqmx86_gpio_write(gpio, irq_status, TQMX86_GPIIS);
289
290 ret = gpiochip_irqchip_add(chip, irq_chip,
291 0, handle_simple_irq,
292 IRQ_TYPE_EDGE_BOTH);
293 if (ret) {
294 dev_err(dev, "Could not add irq chip\n");
295 goto out_pm_dis;
296 }
297
298 gpiochip_set_chained_irqchip(chip, irq_chip,
299 irq, tqmx86_gpio_irq_handler);
300 }
301
302 /* Only GPIOs 4-7 are valid for interrupts. Clear the others */
303 clear_bit(0, chip->irq.valid_mask);
304 clear_bit(1, chip->irq.valid_mask);
305 clear_bit(2, chip->irq.valid_mask);
306 clear_bit(3, chip->irq.valid_mask);
307
308 dev_info(dev, "GPIO functionality initialized with %d pins\n",
309 chip->ngpio);
310
311 return 0;
312
313out_pm_dis:
314 pm_runtime_disable(&pdev->dev);
315
316 return ret;
317}
318
319static struct platform_driver tqmx86_gpio_driver = {
320 .driver = {
321 .name = "tqmx86-gpio",
322 .pm = &tqmx86_gpio_dev_pm_ops,
323 },
324 .probe = tqmx86_gpio_probe,
325};
326
327module_platform_driver(tqmx86_gpio_driver);
328
329MODULE_DESCRIPTION("TQMx86 PLD GPIO Driver");
330MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
331MODULE_LICENSE("GPL");
332MODULE_ALIAS("platform:tqmx86-gpio");
333