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1// SPDX-License-Identifier: GPL-2.0
2//
3// IXP4 GPIO driver
4// Copyright (C) 2019 Linus Walleij <linus.walleij@linaro.org>
5//
6// based on previous work and know-how from:
7// Deepak Saxena <dsaxena@plexity.net>
8
9#include <linux/gpio/driver.h>
10#include <linux/io.h>
11#include <linux/irq.h>
12#include <linux/irqdomain.h>
13#include <linux/irqchip.h>
14#include <linux/of_irq.h>
15#include <linux/platform_device.h>
16#include <linux/bitops.h>
17
18#define IXP4XX_REG_GPOUT 0x00
19#define IXP4XX_REG_GPOE 0x04
20#define IXP4XX_REG_GPIN 0x08
21#define IXP4XX_REG_GPIS 0x0C
22#define IXP4XX_REG_GPIT1 0x10
23#define IXP4XX_REG_GPIT2 0x14
24#define IXP4XX_REG_GPCLK 0x18
25#define IXP4XX_REG_GPDBSEL 0x1C
26
27/*
28 * The hardware uses 3 bits to indicate interrupt "style".
29 * we clear and set these three bits accordingly. The lower 24
30 * bits in two registers (GPIT1 and GPIT2) are used to set up
31 * the style for 8 lines each for a total of 16 GPIO lines.
32 */
33#define IXP4XX_GPIO_STYLE_ACTIVE_HIGH 0x0
34#define IXP4XX_GPIO_STYLE_ACTIVE_LOW 0x1
35#define IXP4XX_GPIO_STYLE_RISING_EDGE 0x2
36#define IXP4XX_GPIO_STYLE_FALLING_EDGE 0x3
37#define IXP4XX_GPIO_STYLE_TRANSITIONAL 0x4
38#define IXP4XX_GPIO_STYLE_MASK GENMASK(2, 0)
39#define IXP4XX_GPIO_STYLE_SIZE 3
40
41/**
42 * struct ixp4xx_gpio - IXP4 GPIO state container
43 * @dev: containing device for this instance
44 * @fwnode: the fwnode for this GPIO chip
45 * @gc: gpiochip for this instance
46 * @base: remapped I/O-memory base
47 * @irq_edge: Each bit represents an IRQ: 1: edge-triggered,
48 * 0: level triggered
49 */
50struct ixp4xx_gpio {
51 struct device *dev;
52 struct fwnode_handle *fwnode;
53 struct gpio_chip gc;
54 void __iomem *base;
55 unsigned long long irq_edge;
56};
57
58static void ixp4xx_gpio_irq_ack(struct irq_data *d)
59{
60 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
61 struct ixp4xx_gpio *g = gpiochip_get_data(gc);
62
63 __raw_writel(BIT(d->hwirq), g->base + IXP4XX_REG_GPIS);
64}
65
66static void ixp4xx_gpio_mask_irq(struct irq_data *d)
67{
68 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
69
70 irq_chip_mask_parent(d);
71 gpiochip_disable_irq(gc, d->hwirq);
72}
73
74static void ixp4xx_gpio_irq_unmask(struct irq_data *d)
75{
76 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
77 struct ixp4xx_gpio *g = gpiochip_get_data(gc);
78
79 /* ACK when unmasking if not edge-triggered */
80 if (!(g->irq_edge & BIT(d->hwirq)))
81 ixp4xx_gpio_irq_ack(d);
82
83 gpiochip_enable_irq(gc, d->hwirq);
84 irq_chip_unmask_parent(d);
85}
86
87static int ixp4xx_gpio_irq_set_type(struct irq_data *d, unsigned int type)
88{
89 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
90 struct ixp4xx_gpio *g = gpiochip_get_data(gc);
91 int line = d->hwirq;
92 unsigned long flags;
93 u32 int_style;
94 u32 int_reg;
95 u32 val;
96
97 switch (type) {
98 case IRQ_TYPE_EDGE_BOTH:
99 irq_set_handler_locked(d, handle_edge_irq);
100 int_style = IXP4XX_GPIO_STYLE_TRANSITIONAL;
101 g->irq_edge |= BIT(d->hwirq);
102 break;
103 case IRQ_TYPE_EDGE_RISING:
104 irq_set_handler_locked(d, handle_edge_irq);
105 int_style = IXP4XX_GPIO_STYLE_RISING_EDGE;
106 g->irq_edge |= BIT(d->hwirq);
107 break;
108 case IRQ_TYPE_EDGE_FALLING:
109 irq_set_handler_locked(d, handle_edge_irq);
110 int_style = IXP4XX_GPIO_STYLE_FALLING_EDGE;
111 g->irq_edge |= BIT(d->hwirq);
112 break;
113 case IRQ_TYPE_LEVEL_HIGH:
114 irq_set_handler_locked(d, handle_level_irq);
115 int_style = IXP4XX_GPIO_STYLE_ACTIVE_HIGH;
116 g->irq_edge &= ~BIT(d->hwirq);
117 break;
118 case IRQ_TYPE_LEVEL_LOW:
119 irq_set_handler_locked(d, handle_level_irq);
120 int_style = IXP4XX_GPIO_STYLE_ACTIVE_LOW;
121 g->irq_edge &= ~BIT(d->hwirq);
122 break;
123 default:
124 return -EINVAL;
125 }
126
127 if (line >= 8) {
128 /* pins 8-15 */
129 line -= 8;
130 int_reg = IXP4XX_REG_GPIT2;
131 } else {
132 /* pins 0-7 */
133 int_reg = IXP4XX_REG_GPIT1;
134 }
135
136 raw_spin_lock_irqsave(&g->gc.bgpio_lock, flags);
137
138 /* Clear the style for the appropriate pin */
139 val = __raw_readl(g->base + int_reg);
140 val &= ~(IXP4XX_GPIO_STYLE_MASK << (line * IXP4XX_GPIO_STYLE_SIZE));
141 __raw_writel(val, g->base + int_reg);
142
143 __raw_writel(BIT(line), g->base + IXP4XX_REG_GPIS);
144
145 /* Set the new style */
146 val = __raw_readl(g->base + int_reg);
147 val |= (int_style << (line * IXP4XX_GPIO_STYLE_SIZE));
148 __raw_writel(val, g->base + int_reg);
149
150 /* Force-configure this line as an input */
151 val = __raw_readl(g->base + IXP4XX_REG_GPOE);
152 val |= BIT(d->hwirq);
153 __raw_writel(val, g->base + IXP4XX_REG_GPOE);
154
155 raw_spin_unlock_irqrestore(&g->gc.bgpio_lock, flags);
156
157 /* This parent only accept level high (asserted) */
158 return irq_chip_set_type_parent(d, IRQ_TYPE_LEVEL_HIGH);
159}
160
161static const struct irq_chip ixp4xx_gpio_irqchip = {
162 .name = "IXP4GPIO",
163 .irq_ack = ixp4xx_gpio_irq_ack,
164 .irq_mask = ixp4xx_gpio_mask_irq,
165 .irq_unmask = ixp4xx_gpio_irq_unmask,
166 .irq_set_type = ixp4xx_gpio_irq_set_type,
167 .flags = IRQCHIP_IMMUTABLE,
168 GPIOCHIP_IRQ_RESOURCE_HELPERS,
169};
170
171static int ixp4xx_gpio_child_to_parent_hwirq(struct gpio_chip *gc,
172 unsigned int child,
173 unsigned int child_type,
174 unsigned int *parent,
175 unsigned int *parent_type)
176{
177 /* All these interrupts are level high in the CPU */
178 *parent_type = IRQ_TYPE_LEVEL_HIGH;
179
180 /* GPIO lines 0..12 have dedicated IRQs */
181 if (child == 0) {
182 *parent = 6;
183 return 0;
184 }
185 if (child == 1) {
186 *parent = 7;
187 return 0;
188 }
189 if (child >= 2 && child <= 12) {
190 *parent = child + 17;
191 return 0;
192 }
193 return -EINVAL;
194}
195
196static int ixp4xx_gpio_probe(struct platform_device *pdev)
197{
198 unsigned long flags;
199 struct device *dev = &pdev->dev;
200 struct device_node *np = dev->of_node;
201 struct irq_domain *parent;
202 struct resource *res;
203 struct ixp4xx_gpio *g;
204 struct gpio_irq_chip *girq;
205 struct device_node *irq_parent;
206 int ret;
207
208 g = devm_kzalloc(dev, sizeof(*g), GFP_KERNEL);
209 if (!g)
210 return -ENOMEM;
211 g->dev = dev;
212
213 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
214 g->base = devm_ioremap_resource(dev, res);
215 if (IS_ERR(g->base))
216 return PTR_ERR(g->base);
217
218 irq_parent = of_irq_find_parent(np);
219 if (!irq_parent) {
220 dev_err(dev, "no IRQ parent node\n");
221 return -ENODEV;
222 }
223 parent = irq_find_host(irq_parent);
224 if (!parent) {
225 dev_err(dev, "no IRQ parent domain\n");
226 return -ENODEV;
227 }
228 g->fwnode = of_node_to_fwnode(np);
229
230 /*
231 * Make sure GPIO 14 and 15 are NOT used as clocks but GPIO on
232 * specific machines.
233 */
234 if (of_machine_is_compatible("dlink,dsm-g600-a") ||
235 of_machine_is_compatible("iom,nas-100d"))
236 __raw_writel(0x0, g->base + IXP4XX_REG_GPCLK);
237
238 /*
239 * This is a very special big-endian ARM issue: when the IXP4xx is
240 * run in big endian mode, all registers in the machine are switched
241 * around to the CPU-native endianness. As you see mostly in the
242 * driver we use __raw_readl()/__raw_writel() to access the registers
243 * in the appropriate order. With the GPIO library we need to specify
244 * byte order explicitly, so this flag needs to be set when compiling
245 * for big endian.
246 */
247#if defined(CONFIG_CPU_BIG_ENDIAN)
248 flags = BGPIOF_BIG_ENDIAN_BYTE_ORDER;
249#else
250 flags = 0;
251#endif
252
253 /* Populate and register gpio chip */
254 ret = bgpio_init(&g->gc, dev, 4,
255 g->base + IXP4XX_REG_GPIN,
256 g->base + IXP4XX_REG_GPOUT,
257 NULL,
258 NULL,
259 g->base + IXP4XX_REG_GPOE,
260 flags);
261 if (ret) {
262 dev_err(dev, "unable to init generic GPIO\n");
263 return ret;
264 }
265 g->gc.ngpio = 16;
266 g->gc.label = "IXP4XX_GPIO_CHIP";
267 /*
268 * TODO: when we have migrated to device tree and all GPIOs
269 * are fetched using phandles, set this to -1 to get rid of
270 * the fixed gpiochip base.
271 */
272 g->gc.base = 0;
273 g->gc.parent = &pdev->dev;
274 g->gc.owner = THIS_MODULE;
275
276 girq = &g->gc.irq;
277 gpio_irq_chip_set_chip(girq, &ixp4xx_gpio_irqchip);
278 girq->fwnode = g->fwnode;
279 girq->parent_domain = parent;
280 girq->child_to_parent_hwirq = ixp4xx_gpio_child_to_parent_hwirq;
281 girq->handler = handle_bad_irq;
282 girq->default_type = IRQ_TYPE_NONE;
283
284 ret = devm_gpiochip_add_data(dev, &g->gc, g);
285 if (ret) {
286 dev_err(dev, "failed to add SoC gpiochip\n");
287 return ret;
288 }
289
290 platform_set_drvdata(pdev, g);
291 dev_info(dev, "IXP4 GPIO registered\n");
292
293 return 0;
294}
295
296static const struct of_device_id ixp4xx_gpio_of_match[] = {
297 {
298 .compatible = "intel,ixp4xx-gpio",
299 },
300 {},
301};
302
303
304static struct platform_driver ixp4xx_gpio_driver = {
305 .driver = {
306 .name = "ixp4xx-gpio",
307 .of_match_table = of_match_ptr(ixp4xx_gpio_of_match),
308 },
309 .probe = ixp4xx_gpio_probe,
310};
311builtin_platform_driver(ixp4xx_gpio_driver);