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/bitops.h>
10 #include <linux/gpio/driver.h>
11 #include <linux/io.h>
12 #include <linux/irq.h>
13 #include <linux/irqdomain.h>
14 #include <linux/irqchip.h>
15 #include <linux/of_irq.h>
16 #include <linux/platform_device.h>
17 #include <linux/property.h>
18
19 #define IXP4XX_REG_GPOUT 0x00
20 #define IXP4XX_REG_GPOE 0x04
21 #define IXP4XX_REG_GPIN 0x08
22 #define IXP4XX_REG_GPIS 0x0C
23 #define IXP4XX_REG_GPIT1 0x10
24 #define IXP4XX_REG_GPIT2 0x14
25 #define IXP4XX_REG_GPCLK 0x18
26 #define IXP4XX_REG_GPDBSEL 0x1C
27
28 /*
29 * The hardware uses 3 bits to indicate interrupt "style".
30 * we clear and set these three bits accordingly. The lower 24
31 * bits in two registers (GPIT1 and GPIT2) are used to set up
32 * the style for 8 lines each for a total of 16 GPIO lines.
33 */
34 #define IXP4XX_GPIO_STYLE_ACTIVE_HIGH 0x0
35 #define IXP4XX_GPIO_STYLE_ACTIVE_LOW 0x1
36 #define IXP4XX_GPIO_STYLE_RISING_EDGE 0x2
37 #define IXP4XX_GPIO_STYLE_FALLING_EDGE 0x3
38 #define IXP4XX_GPIO_STYLE_TRANSITIONAL 0x4
39 #define IXP4XX_GPIO_STYLE_MASK GENMASK(2, 0)
40 #define IXP4XX_GPIO_STYLE_SIZE 3
41
42 /*
43 * Clock output control register defines.
44 */
45 #define IXP4XX_GPCLK_CLK0DC_SHIFT 0
46 #define IXP4XX_GPCLK_CLK0TC_SHIFT 4
47 #define IXP4XX_GPCLK_CLK0_MASK GENMASK(7, 0)
48 #define IXP4XX_GPCLK_MUX14 BIT(8)
49 #define IXP4XX_GPCLK_CLK1DC_SHIFT 16
50 #define IXP4XX_GPCLK_CLK1TC_SHIFT 20
51 #define IXP4XX_GPCLK_CLK1_MASK GENMASK(23, 16)
52 #define IXP4XX_GPCLK_MUX15 BIT(24)
53
54 /**
55 * struct ixp4xx_gpio - IXP4 GPIO state container
56 * @dev: containing device for this instance
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 */
62 struct ixp4xx_gpio {
63 struct gpio_chip gc;
64 struct device *dev;
65 void __iomem *base;
66 unsigned long long irq_edge;
67 };
68
ixp4xx_gpio_irq_ack(struct irq_data * d)69 static void ixp4xx_gpio_irq_ack(struct irq_data *d)
70 {
71 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
72 struct ixp4xx_gpio *g = gpiochip_get_data(gc);
73
74 __raw_writel(BIT(d->hwirq), g->base + IXP4XX_REG_GPIS);
75 }
76
ixp4xx_gpio_mask_irq(struct irq_data * d)77 static void ixp4xx_gpio_mask_irq(struct irq_data *d)
78 {
79 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
80
81 irq_chip_mask_parent(d);
82 gpiochip_disable_irq(gc, d->hwirq);
83 }
84
ixp4xx_gpio_irq_unmask(struct irq_data * d)85 static void ixp4xx_gpio_irq_unmask(struct irq_data *d)
86 {
87 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
88 struct ixp4xx_gpio *g = gpiochip_get_data(gc);
89
90 /* ACK when unmasking if not edge-triggered */
91 if (!(g->irq_edge & BIT(d->hwirq)))
92 ixp4xx_gpio_irq_ack(d);
93
94 gpiochip_enable_irq(gc, d->hwirq);
95 irq_chip_unmask_parent(d);
96 }
97
ixp4xx_gpio_irq_set_type(struct irq_data * d,unsigned int type)98 static int ixp4xx_gpio_irq_set_type(struct irq_data *d, unsigned int type)
99 {
100 struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
101 struct ixp4xx_gpio *g = gpiochip_get_data(gc);
102 int line = d->hwirq;
103 unsigned long flags;
104 u32 int_style;
105 u32 int_reg;
106 u32 val;
107
108 switch (type) {
109 case IRQ_TYPE_EDGE_BOTH:
110 irq_set_handler_locked(d, handle_edge_irq);
111 int_style = IXP4XX_GPIO_STYLE_TRANSITIONAL;
112 g->irq_edge |= BIT(d->hwirq);
113 break;
114 case IRQ_TYPE_EDGE_RISING:
115 irq_set_handler_locked(d, handle_edge_irq);
116 int_style = IXP4XX_GPIO_STYLE_RISING_EDGE;
117 g->irq_edge |= BIT(d->hwirq);
118 break;
119 case IRQ_TYPE_EDGE_FALLING:
120 irq_set_handler_locked(d, handle_edge_irq);
121 int_style = IXP4XX_GPIO_STYLE_FALLING_EDGE;
122 g->irq_edge |= BIT(d->hwirq);
123 break;
124 case IRQ_TYPE_LEVEL_HIGH:
125 irq_set_handler_locked(d, handle_level_irq);
126 int_style = IXP4XX_GPIO_STYLE_ACTIVE_HIGH;
127 g->irq_edge &= ~BIT(d->hwirq);
128 break;
129 case IRQ_TYPE_LEVEL_LOW:
130 irq_set_handler_locked(d, handle_level_irq);
131 int_style = IXP4XX_GPIO_STYLE_ACTIVE_LOW;
132 g->irq_edge &= ~BIT(d->hwirq);
133 break;
134 default:
135 return -EINVAL;
136 }
137
138 if (line >= 8) {
139 /* pins 8-15 */
140 line -= 8;
141 int_reg = IXP4XX_REG_GPIT2;
142 } else {
143 /* pins 0-7 */
144 int_reg = IXP4XX_REG_GPIT1;
145 }
146
147 raw_spin_lock_irqsave(&g->gc.bgpio_lock, flags);
148
149 /* Clear the style for the appropriate pin */
150 val = __raw_readl(g->base + int_reg);
151 val &= ~(IXP4XX_GPIO_STYLE_MASK << (line * IXP4XX_GPIO_STYLE_SIZE));
152 __raw_writel(val, g->base + int_reg);
153
154 __raw_writel(BIT(line), g->base + IXP4XX_REG_GPIS);
155
156 /* Set the new style */
157 val = __raw_readl(g->base + int_reg);
158 val |= (int_style << (line * IXP4XX_GPIO_STYLE_SIZE));
159 __raw_writel(val, g->base + int_reg);
160
161 /* Force-configure this line as an input */
162 val = __raw_readl(g->base + IXP4XX_REG_GPOE);
163 val |= BIT(d->hwirq);
164 __raw_writel(val, g->base + IXP4XX_REG_GPOE);
165
166 raw_spin_unlock_irqrestore(&g->gc.bgpio_lock, flags);
167
168 /* This parent only accept level high (asserted) */
169 return irq_chip_set_type_parent(d, IRQ_TYPE_LEVEL_HIGH);
170 }
171
172 static const struct irq_chip ixp4xx_gpio_irqchip = {
173 .name = "IXP4GPIO",
174 .irq_ack = ixp4xx_gpio_irq_ack,
175 .irq_mask = ixp4xx_gpio_mask_irq,
176 .irq_unmask = ixp4xx_gpio_irq_unmask,
177 .irq_set_type = ixp4xx_gpio_irq_set_type,
178 .flags = IRQCHIP_IMMUTABLE,
179 GPIOCHIP_IRQ_RESOURCE_HELPERS,
180 };
181
ixp4xx_gpio_child_to_parent_hwirq(struct gpio_chip * gc,unsigned int child,unsigned int child_type,unsigned int * parent,unsigned int * parent_type)182 static int ixp4xx_gpio_child_to_parent_hwirq(struct gpio_chip *gc,
183 unsigned int child,
184 unsigned int child_type,
185 unsigned int *parent,
186 unsigned int *parent_type)
187 {
188 /* All these interrupts are level high in the CPU */
189 *parent_type = IRQ_TYPE_LEVEL_HIGH;
190
191 /* GPIO lines 0..12 have dedicated IRQs */
192 if (child == 0) {
193 *parent = 6;
194 return 0;
195 }
196 if (child == 1) {
197 *parent = 7;
198 return 0;
199 }
200 if (child >= 2 && child <= 12) {
201 *parent = child + 17;
202 return 0;
203 }
204 return -EINVAL;
205 }
206
ixp4xx_gpio_probe(struct platform_device * pdev)207 static int ixp4xx_gpio_probe(struct platform_device *pdev)
208 {
209 unsigned long flags;
210 struct device *dev = &pdev->dev;
211 struct device_node *np = dev->of_node;
212 struct irq_domain *parent;
213 struct ixp4xx_gpio *g;
214 struct gpio_irq_chip *girq;
215 struct device_node *irq_parent;
216 bool clk_14, clk_15;
217 u32 val;
218 int ret;
219
220 g = devm_kzalloc(dev, sizeof(*g), GFP_KERNEL);
221 if (!g)
222 return -ENOMEM;
223 g->dev = dev;
224
225 g->base = devm_platform_ioremap_resource(pdev, 0);
226 if (IS_ERR(g->base))
227 return PTR_ERR(g->base);
228
229 irq_parent = of_irq_find_parent(np);
230 if (!irq_parent) {
231 dev_err(dev, "no IRQ parent node\n");
232 return -ENODEV;
233 }
234 parent = irq_find_host(irq_parent);
235 if (!parent) {
236 dev_err(dev, "no IRQ parent domain\n");
237 return -ENODEV;
238 }
239
240 /*
241 * If either clock output is enabled explicitly in the device tree
242 * we take full control of the clock by masking off all bits for
243 * the clock control and selectively enabling them. Otherwise
244 * we leave the hardware default settings.
245 *
246 * Enable clock outputs with default timings of requested clock.
247 * If you need control over TC and DC, add these to the device
248 * tree bindings and use them here.
249 */
250 clk_14 = of_property_read_bool(np, "intel,ixp4xx-gpio14-clkout");
251 clk_15 = of_property_read_bool(np, "intel,ixp4xx-gpio15-clkout");
252
253 /*
254 * Make sure GPIO 14 and 15 are NOT used as clocks but GPIO on
255 * specific machines.
256 */
257 if (of_machine_is_compatible("dlink,dsm-g600-a") ||
258 of_machine_is_compatible("iom,nas-100d"))
259 val = 0;
260 else {
261 val = __raw_readl(g->base + IXP4XX_REG_GPCLK);
262
263 if (clk_14 || clk_15) {
264 val &= ~(IXP4XX_GPCLK_MUX14 | IXP4XX_GPCLK_MUX15);
265 val &= ~IXP4XX_GPCLK_CLK0_MASK;
266 val &= ~IXP4XX_GPCLK_CLK1_MASK;
267 if (clk_14) {
268 /* IXP4XX_GPCLK_CLK0DC implicit low */
269 val |= (1 << IXP4XX_GPCLK_CLK0TC_SHIFT);
270 val |= IXP4XX_GPCLK_MUX14;
271 }
272
273 if (clk_15) {
274 /* IXP4XX_GPCLK_CLK1DC implicit low */
275 val |= (1 << IXP4XX_GPCLK_CLK1TC_SHIFT);
276 val |= IXP4XX_GPCLK_MUX15;
277 }
278 }
279 }
280
281 __raw_writel(val, g->base + IXP4XX_REG_GPCLK);
282
283 /*
284 * This is a very special big-endian ARM issue: when the IXP4xx is
285 * run in big endian mode, all registers in the machine are switched
286 * around to the CPU-native endianness. As you see mostly in the
287 * driver we use __raw_readl()/__raw_writel() to access the registers
288 * in the appropriate order. With the GPIO library we need to specify
289 * byte order explicitly, so this flag needs to be set when compiling
290 * for big endian.
291 */
292 #if defined(CONFIG_CPU_BIG_ENDIAN)
293 flags = BGPIOF_BIG_ENDIAN_BYTE_ORDER;
294 #else
295 flags = 0;
296 #endif
297
298 /* Populate and register gpio chip */
299 ret = bgpio_init(&g->gc, dev, 4,
300 g->base + IXP4XX_REG_GPIN,
301 g->base + IXP4XX_REG_GPOUT,
302 NULL,
303 NULL,
304 g->base + IXP4XX_REG_GPOE,
305 flags);
306 if (ret) {
307 dev_err(dev, "unable to init generic GPIO\n");
308 return ret;
309 }
310 g->gc.ngpio = 16;
311 g->gc.label = "IXP4XX_GPIO_CHIP";
312 /*
313 * TODO: when we have migrated to device tree and all GPIOs
314 * are fetched using phandles, set this to -1 to get rid of
315 * the fixed gpiochip base.
316 */
317 g->gc.base = 0;
318 g->gc.parent = &pdev->dev;
319 g->gc.owner = THIS_MODULE;
320
321 girq = &g->gc.irq;
322 gpio_irq_chip_set_chip(girq, &ixp4xx_gpio_irqchip);
323 girq->fwnode = dev_fwnode(dev);
324 girq->parent_domain = parent;
325 girq->child_to_parent_hwirq = ixp4xx_gpio_child_to_parent_hwirq;
326 girq->handler = handle_bad_irq;
327 girq->default_type = IRQ_TYPE_NONE;
328
329 ret = devm_gpiochip_add_data(dev, &g->gc, g);
330 if (ret) {
331 dev_err(dev, "failed to add SoC gpiochip\n");
332 return ret;
333 }
334
335 platform_set_drvdata(pdev, g);
336 dev_info(dev, "IXP4 GPIO registered\n");
337
338 return 0;
339 }
340
341 static const struct of_device_id ixp4xx_gpio_of_match[] = {
342 {
343 .compatible = "intel,ixp4xx-gpio",
344 },
345 {},
346 };
347
348
349 static struct platform_driver ixp4xx_gpio_driver = {
350 .driver = {
351 .name = "ixp4xx-gpio",
352 .of_match_table = ixp4xx_gpio_of_match,
353 },
354 .probe = ixp4xx_gpio_probe,
355 };
356 builtin_platform_driver(ixp4xx_gpio_driver);
357