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 */ 50 struct 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 58 static 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 66 static 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 74 static 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 87 static 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 } 160 161 static 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 }; 170 171 static 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 } 195 196 static 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 ixp4xx_gpio *g; 203 struct gpio_irq_chip *girq; 204 struct device_node *irq_parent; 205 int ret; 206 207 g = devm_kzalloc(dev, sizeof(*g), GFP_KERNEL); 208 if (!g) 209 return -ENOMEM; 210 g->dev = dev; 211 212 g->base = devm_platform_ioremap_resource(pdev, 0); 213 if (IS_ERR(g->base)) 214 return PTR_ERR(g->base); 215 216 irq_parent = of_irq_find_parent(np); 217 if (!irq_parent) { 218 dev_err(dev, "no IRQ parent node\n"); 219 return -ENODEV; 220 } 221 parent = irq_find_host(irq_parent); 222 if (!parent) { 223 dev_err(dev, "no IRQ parent domain\n"); 224 return -ENODEV; 225 } 226 g->fwnode = of_node_to_fwnode(np); 227 228 /* 229 * Make sure GPIO 14 and 15 are NOT used as clocks but GPIO on 230 * specific machines. 231 */ 232 if (of_machine_is_compatible("dlink,dsm-g600-a") || 233 of_machine_is_compatible("iom,nas-100d")) 234 __raw_writel(0x0, g->base + IXP4XX_REG_GPCLK); 235 236 /* 237 * This is a very special big-endian ARM issue: when the IXP4xx is 238 * run in big endian mode, all registers in the machine are switched 239 * around to the CPU-native endianness. As you see mostly in the 240 * driver we use __raw_readl()/__raw_writel() to access the registers 241 * in the appropriate order. With the GPIO library we need to specify 242 * byte order explicitly, so this flag needs to be set when compiling 243 * for big endian. 244 */ 245 #if defined(CONFIG_CPU_BIG_ENDIAN) 246 flags = BGPIOF_BIG_ENDIAN_BYTE_ORDER; 247 #else 248 flags = 0; 249 #endif 250 251 /* Populate and register gpio chip */ 252 ret = bgpio_init(&g->gc, dev, 4, 253 g->base + IXP4XX_REG_GPIN, 254 g->base + IXP4XX_REG_GPOUT, 255 NULL, 256 NULL, 257 g->base + IXP4XX_REG_GPOE, 258 flags); 259 if (ret) { 260 dev_err(dev, "unable to init generic GPIO\n"); 261 return ret; 262 } 263 g->gc.ngpio = 16; 264 g->gc.label = "IXP4XX_GPIO_CHIP"; 265 /* 266 * TODO: when we have migrated to device tree and all GPIOs 267 * are fetched using phandles, set this to -1 to get rid of 268 * the fixed gpiochip base. 269 */ 270 g->gc.base = 0; 271 g->gc.parent = &pdev->dev; 272 g->gc.owner = THIS_MODULE; 273 274 girq = &g->gc.irq; 275 gpio_irq_chip_set_chip(girq, &ixp4xx_gpio_irqchip); 276 girq->fwnode = g->fwnode; 277 girq->parent_domain = parent; 278 girq->child_to_parent_hwirq = ixp4xx_gpio_child_to_parent_hwirq; 279 girq->handler = handle_bad_irq; 280 girq->default_type = IRQ_TYPE_NONE; 281 282 ret = devm_gpiochip_add_data(dev, &g->gc, g); 283 if (ret) { 284 dev_err(dev, "failed to add SoC gpiochip\n"); 285 return ret; 286 } 287 288 platform_set_drvdata(pdev, g); 289 dev_info(dev, "IXP4 GPIO registered\n"); 290 291 return 0; 292 } 293 294 static const struct of_device_id ixp4xx_gpio_of_match[] = { 295 { 296 .compatible = "intel,ixp4xx-gpio", 297 }, 298 {}, 299 }; 300 301 302 static struct platform_driver ixp4xx_gpio_driver = { 303 .driver = { 304 .name = "ixp4xx-gpio", 305 .of_match_table = ixp4xx_gpio_of_match, 306 }, 307 .probe = ixp4xx_gpio_probe, 308 }; 309 builtin_platform_driver(ixp4xx_gpio_driver); 310