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 * Clock output control register defines.
43 */
44#define IXP4XX_GPCLK_CLK0DC_SHIFT 0
45#define IXP4XX_GPCLK_CLK0TC_SHIFT 4
46#define IXP4XX_GPCLK_CLK0_MASK GENMASK(7, 0)
47#define IXP4XX_GPCLK_MUX14 BIT(8)
48#define IXP4XX_GPCLK_CLK1DC_SHIFT 16
49#define IXP4XX_GPCLK_CLK1TC_SHIFT 20
50#define IXP4XX_GPCLK_CLK1_MASK GENMASK(23, 16)
51#define IXP4XX_GPCLK_MUX15 BIT(24)
52
53/**
54 * struct ixp4xx_gpio - IXP4 GPIO state container
55 * @dev: containing device for this instance
56 * @fwnode: the fwnode for this GPIO chip
57 * @gc: gpiochip for this instance
58 * @base: remapped I/O-memory base
59 * @irq_edge: Each bit represents an IRQ: 1: edge-triggered,
60 * 0: level triggered
61 */
62struct ixp4xx_gpio {
63 struct device *dev;
64 struct fwnode_handle *fwnode;
65 struct gpio_chip gc;
66 void __iomem *base;
67 unsigned long long irq_edge;
68};
69
70static void ixp4xx_gpio_irq_ack(struct irq_data *d)
71{
72 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
73 struct ixp4xx_gpio *g = gpiochip_get_data(gc);
74
75 __raw_writel(BIT(d->hwirq), addr: g->base + IXP4XX_REG_GPIS);
76}
77
78static void ixp4xx_gpio_mask_irq(struct irq_data *d)
79{
80 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
81
82 irq_chip_mask_parent(data: d);
83 gpiochip_disable_irq(gc, offset: d->hwirq);
84}
85
86static void ixp4xx_gpio_irq_unmask(struct irq_data *d)
87{
88 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
89 struct ixp4xx_gpio *g = gpiochip_get_data(gc);
90
91 /* ACK when unmasking if not edge-triggered */
92 if (!(g->irq_edge & BIT(d->hwirq)))
93 ixp4xx_gpio_irq_ack(d);
94
95 gpiochip_enable_irq(gc, offset: d->hwirq);
96 irq_chip_unmask_parent(data: d);
97}
98
99static int ixp4xx_gpio_irq_set_type(struct irq_data *d, unsigned int type)
100{
101 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
102 struct ixp4xx_gpio *g = gpiochip_get_data(gc);
103 int line = d->hwirq;
104 unsigned long flags;
105 u32 int_style;
106 u32 int_reg;
107 u32 val;
108
109 switch (type) {
110 case IRQ_TYPE_EDGE_BOTH:
111 irq_set_handler_locked(data: d, handler: handle_edge_irq);
112 int_style = IXP4XX_GPIO_STYLE_TRANSITIONAL;
113 g->irq_edge |= BIT(d->hwirq);
114 break;
115 case IRQ_TYPE_EDGE_RISING:
116 irq_set_handler_locked(data: d, handler: handle_edge_irq);
117 int_style = IXP4XX_GPIO_STYLE_RISING_EDGE;
118 g->irq_edge |= BIT(d->hwirq);
119 break;
120 case IRQ_TYPE_EDGE_FALLING:
121 irq_set_handler_locked(data: d, handler: handle_edge_irq);
122 int_style = IXP4XX_GPIO_STYLE_FALLING_EDGE;
123 g->irq_edge |= BIT(d->hwirq);
124 break;
125 case IRQ_TYPE_LEVEL_HIGH:
126 irq_set_handler_locked(data: d, handler: handle_level_irq);
127 int_style = IXP4XX_GPIO_STYLE_ACTIVE_HIGH;
128 g->irq_edge &= ~BIT(d->hwirq);
129 break;
130 case IRQ_TYPE_LEVEL_LOW:
131 irq_set_handler_locked(data: d, handler: handle_level_irq);
132 int_style = IXP4XX_GPIO_STYLE_ACTIVE_LOW;
133 g->irq_edge &= ~BIT(d->hwirq);
134 break;
135 default:
136 return -EINVAL;
137 }
138
139 if (line >= 8) {
140 /* pins 8-15 */
141 line -= 8;
142 int_reg = IXP4XX_REG_GPIT2;
143 } else {
144 /* pins 0-7 */
145 int_reg = IXP4XX_REG_GPIT1;
146 }
147
148 raw_spin_lock_irqsave(&g->gc.bgpio_lock, flags);
149
150 /* Clear the style for the appropriate pin */
151 val = __raw_readl(addr: g->base + int_reg);
152 val &= ~(IXP4XX_GPIO_STYLE_MASK << (line * IXP4XX_GPIO_STYLE_SIZE));
153 __raw_writel(val, addr: g->base + int_reg);
154
155 __raw_writel(BIT(line), addr: g->base + IXP4XX_REG_GPIS);
156
157 /* Set the new style */
158 val = __raw_readl(addr: g->base + int_reg);
159 val |= (int_style << (line * IXP4XX_GPIO_STYLE_SIZE));
160 __raw_writel(val, addr: g->base + int_reg);
161
162 /* Force-configure this line as an input */
163 val = __raw_readl(addr: g->base + IXP4XX_REG_GPOE);
164 val |= BIT(d->hwirq);
165 __raw_writel(val, addr: g->base + IXP4XX_REG_GPOE);
166
167 raw_spin_unlock_irqrestore(&g->gc.bgpio_lock, flags);
168
169 /* This parent only accept level high (asserted) */
170 return irq_chip_set_type_parent(data: d, type: IRQ_TYPE_LEVEL_HIGH);
171}
172
173static const struct irq_chip ixp4xx_gpio_irqchip = {
174 .name = "IXP4GPIO",
175 .irq_ack = ixp4xx_gpio_irq_ack,
176 .irq_mask = ixp4xx_gpio_mask_irq,
177 .irq_unmask = ixp4xx_gpio_irq_unmask,
178 .irq_set_type = ixp4xx_gpio_irq_set_type,
179 .flags = IRQCHIP_IMMUTABLE,
180 GPIOCHIP_IRQ_RESOURCE_HELPERS,
181};
182
183static int ixp4xx_gpio_child_to_parent_hwirq(struct gpio_chip *gc,
184 unsigned int child,
185 unsigned int child_type,
186 unsigned int *parent,
187 unsigned int *parent_type)
188{
189 /* All these interrupts are level high in the CPU */
190 *parent_type = IRQ_TYPE_LEVEL_HIGH;
191
192 /* GPIO lines 0..12 have dedicated IRQs */
193 if (child == 0) {
194 *parent = 6;
195 return 0;
196 }
197 if (child == 1) {
198 *parent = 7;
199 return 0;
200 }
201 if (child >= 2 && child <= 12) {
202 *parent = child + 17;
203 return 0;
204 }
205 return -EINVAL;
206}
207
208static int ixp4xx_gpio_probe(struct platform_device *pdev)
209{
210 unsigned long flags;
211 struct device *dev = &pdev->dev;
212 struct device_node *np = dev->of_node;
213 struct irq_domain *parent;
214 struct ixp4xx_gpio *g;
215 struct gpio_irq_chip *girq;
216 struct device_node *irq_parent;
217 bool clk_14, clk_15;
218 u32 val;
219 int ret;
220
221 g = devm_kzalloc(dev, size: sizeof(*g), GFP_KERNEL);
222 if (!g)
223 return -ENOMEM;
224 g->dev = dev;
225
226 g->base = devm_platform_ioremap_resource(pdev, index: 0);
227 if (IS_ERR(ptr: g->base))
228 return PTR_ERR(ptr: g->base);
229
230 irq_parent = of_irq_find_parent(child: np);
231 if (!irq_parent) {
232 dev_err(dev, "no IRQ parent node\n");
233 return -ENODEV;
234 }
235 parent = irq_find_host(node: irq_parent);
236 if (!parent) {
237 dev_err(dev, "no IRQ parent domain\n");
238 return -ENODEV;
239 }
240 g->fwnode = of_node_to_fwnode(node: np);
241
242 /*
243 * If either clock output is enabled explicitly in the device tree
244 * we take full control of the clock by masking off all bits for
245 * the clock control and selectively enabling them. Otherwise
246 * we leave the hardware default settings.
247 *
248 * Enable clock outputs with default timings of requested clock.
249 * If you need control over TC and DC, add these to the device
250 * tree bindings and use them here.
251 */
252 clk_14 = of_property_read_bool(np, propname: "intel,ixp4xx-gpio14-clkout");
253 clk_15 = of_property_read_bool(np, propname: "intel,ixp4xx-gpio15-clkout");
254
255 /*
256 * Make sure GPIO 14 and 15 are NOT used as clocks but GPIO on
257 * specific machines.
258 */
259 if (of_machine_is_compatible(compat: "dlink,dsm-g600-a") ||
260 of_machine_is_compatible(compat: "iom,nas-100d"))
261 val = 0;
262 else {
263 val = __raw_readl(addr: g->base + IXP4XX_REG_GPCLK);
264
265 if (clk_14 || clk_15) {
266 val &= ~(IXP4XX_GPCLK_MUX14 | IXP4XX_GPCLK_MUX15);
267 val &= ~IXP4XX_GPCLK_CLK0_MASK;
268 val &= ~IXP4XX_GPCLK_CLK1_MASK;
269 if (clk_14) {
270 /* IXP4XX_GPCLK_CLK0DC implicit low */
271 val |= (1 << IXP4XX_GPCLK_CLK0TC_SHIFT);
272 val |= IXP4XX_GPCLK_MUX14;
273 }
274
275 if (clk_15) {
276 /* IXP4XX_GPCLK_CLK1DC implicit low */
277 val |= (1 << IXP4XX_GPCLK_CLK1TC_SHIFT);
278 val |= IXP4XX_GPCLK_MUX15;
279 }
280 }
281 }
282
283 __raw_writel(val, addr: g->base + IXP4XX_REG_GPCLK);
284
285 /*
286 * This is a very special big-endian ARM issue: when the IXP4xx is
287 * run in big endian mode, all registers in the machine are switched
288 * around to the CPU-native endianness. As you see mostly in the
289 * driver we use __raw_readl()/__raw_writel() to access the registers
290 * in the appropriate order. With the GPIO library we need to specify
291 * byte order explicitly, so this flag needs to be set when compiling
292 * for big endian.
293 */
294#if defined(CONFIG_CPU_BIG_ENDIAN)
295 flags = BGPIOF_BIG_ENDIAN_BYTE_ORDER;
296#else
297 flags = 0;
298#endif
299
300 /* Populate and register gpio chip */
301 ret = bgpio_init(gc: &g->gc, dev, sz: 4,
302 dat: g->base + IXP4XX_REG_GPIN,
303 set: g->base + IXP4XX_REG_GPOUT,
304 NULL,
305 NULL,
306 dirin: g->base + IXP4XX_REG_GPOE,
307 flags);
308 if (ret) {
309 dev_err(dev, "unable to init generic GPIO\n");
310 return ret;
311 }
312 g->gc.ngpio = 16;
313 g->gc.label = "IXP4XX_GPIO_CHIP";
314 /*
315 * TODO: when we have migrated to device tree and all GPIOs
316 * are fetched using phandles, set this to -1 to get rid of
317 * the fixed gpiochip base.
318 */
319 g->gc.base = 0;
320 g->gc.parent = &pdev->dev;
321 g->gc.owner = THIS_MODULE;
322
323 girq = &g->gc.irq;
324 gpio_irq_chip_set_chip(girq, chip: &ixp4xx_gpio_irqchip);
325 girq->fwnode = g->fwnode;
326 girq->parent_domain = parent;
327 girq->child_to_parent_hwirq = ixp4xx_gpio_child_to_parent_hwirq;
328 girq->handler = handle_bad_irq;
329 girq->default_type = IRQ_TYPE_NONE;
330
331 ret = devm_gpiochip_add_data(dev, &g->gc, g);
332 if (ret) {
333 dev_err(dev, "failed to add SoC gpiochip\n");
334 return ret;
335 }
336
337 platform_set_drvdata(pdev, data: g);
338 dev_info(dev, "IXP4 GPIO registered\n");
339
340 return 0;
341}
342
343static const struct of_device_id ixp4xx_gpio_of_match[] = {
344 {
345 .compatible = "intel,ixp4xx-gpio",
346 },
347 {},
348};
349
350
351static struct platform_driver ixp4xx_gpio_driver = {
352 .driver = {
353 .name = "ixp4xx-gpio",
354 .of_match_table = ixp4xx_gpio_of_match,
355 },
356 .probe = ixp4xx_gpio_probe,
357};
358builtin_platform_driver(ixp4xx_gpio_driver);
359

source code of linux/drivers/gpio/gpio-ixp4xx.c