drivers/irqchip/irq-stm32-exti.c

   1 /*
   2  * Copyright (C) Maxime Coquelin 2015
   3  * Author:  Maxime Coquelin <mcoquelin.stm32@gmail.com>
   4  * License terms:  GNU General Public License (GPL), version 2
   5  */
   6
   7 #include <linux/bitops.h>
   8 #include <linux/interrupt.h>
   9 #include <linux/io.h>
  10 #include <linux/irq.h>
  11 #include <linux/irqchip.h>
  12 #include <linux/irqchip/chained_irq.h>
  13 #include <linux/irqdomain.h>
  14 #include <linux/of_address.h>
  15 #include <linux/of_irq.h>
  16
  17 #define EXTI_IMR        0x0
  18 #define EXTI_EMR        0x4
  19 #define EXTI_RTSR       0x8
  20 #define EXTI_FTSR       0xc
  21 #define EXTI_SWIER      0x10
  22 #define EXTI_PR         0x14
  23
  24 static void stm32_irq_handler(struct irq_desc *desc)
  25 {
  26         struct irq_domain *domain = irq_desc_get_handler_data(desc);
  27         struct irq_chip_generic *gc = domain->gc->gc[0];
  28         struct irq_chip *chip = irq_desc_get_chip(desc);
  29         unsigned long pending;
  30         int n;
  31
  32         chained_irq_enter(chip, desc);
  33
  34         while ((pending = irq_reg_readl(gc, EXTI_PR))) {
  35                 for_each_set_bit(n, &pending, BITS_PER_LONG) {
  36                         generic_handle_irq(irq_find_mapping(domain, n));
  37                         irq_reg_writel(gc, BIT(n), EXTI_PR);
  38                 }
  39         }
  40
  41         chained_irq_exit(chip, desc);
  42 }
  43
  44 static int stm32_irq_set_type(struct irq_data *data, unsigned int type)
  45 {
  46         struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
  47         int pin = data->hwirq;
  48         u32 rtsr, ftsr;
  49
  50         irq_gc_lock(gc);
  51
  52         rtsr = irq_reg_readl(gc, EXTI_RTSR);
  53         ftsr = irq_reg_readl(gc, EXTI_FTSR);
  54
  55         switch (type) {
  56         case IRQ_TYPE_EDGE_RISING:
  57                 rtsr |= BIT(pin);
  58                 ftsr &= ~BIT(pin);
  59                 break;
  60         case IRQ_TYPE_EDGE_FALLING:
  61                 rtsr &= ~BIT(pin);
  62                 ftsr |= BIT(pin);
  63                 break;
  64         case IRQ_TYPE_EDGE_BOTH:
  65                 rtsr |= BIT(pin);
  66                 ftsr |= BIT(pin);
  67                 break;
  68         default:
  69                 irq_gc_unlock(gc);
  70                 return -EINVAL;
  71         }
  72
  73         irq_reg_writel(gc, rtsr, EXTI_RTSR);
  74         irq_reg_writel(gc, ftsr, EXTI_FTSR);
  75
  76         irq_gc_unlock(gc);
  77
  78         return 0;
  79 }
  80
  81 static int stm32_irq_set_wake(struct irq_data *data, unsigned int on)
  82 {
  83         struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
  84         int pin = data->hwirq;
  85         u32 emr;
  86
  87         irq_gc_lock(gc);
  88
  89         emr = irq_reg_readl(gc, EXTI_EMR);
  90         if (on)
  91                 emr |= BIT(pin);
  92         else
  93                 emr &= ~BIT(pin);
  94         irq_reg_writel(gc, emr, EXTI_EMR);
  95
  96         irq_gc_unlock(gc);
  97
  98         return 0;
  99 }
 100
 101 static int stm32_exti_alloc(struct irq_domain *d, unsigned int virq,
 102                             unsigned int nr_irqs, void *data)
 103 {
 104         struct irq_chip_generic *gc = d->gc->gc[0];
 105         struct irq_fwspec *fwspec = data;
 106         irq_hw_number_t hwirq;
 107
 108         hwirq = fwspec->param[0];
 109
 110         irq_map_generic_chip(d, virq, hwirq);
 111         irq_domain_set_info(d, virq, hwirq, &gc->chip_types->chip, gc,
 112                             handle_simple_irq, NULL, NULL);
 113
 114         return 0;
 115 }
 116
 117 static void stm32_exti_free(struct irq_domain *d, unsigned int virq,
 118                             unsigned int nr_irqs)
 119 {
 120         struct irq_data *data = irq_domain_get_irq_data(d, virq);
 121
 122         irq_domain_reset_irq_data(data);
 123 }
 124
 125 struct irq_domain_ops irq_exti_domain_ops = {
 126         .map    = irq_map_generic_chip,
 127         .xlate  = irq_domain_xlate_onetwocell,
 128         .alloc  = stm32_exti_alloc,
 129         .free   = stm32_exti_free,
 130 };
 131
 132 static int __init stm32_exti_init(struct device_node *node,
 133                                   struct device_node *parent)
 134 {
 135         unsigned int clr = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
 136         int nr_irqs, nr_exti, ret, i;
 137         struct irq_chip_generic *gc;
 138         struct irq_domain *domain;
 139         void *base;
 140
 141         base = of_iomap(node, 0);
 142         if (!base) {
 143                 pr_err("%s: Unable to map registers\n", node->full_name);
 144                 return -ENOMEM;
 145         }
 146
 147         /* Determine number of irqs supported */
 148         writel_relaxed(~0UL, base + EXTI_RTSR);
 149         nr_exti = fls(readl_relaxed(base + EXTI_RTSR));
 150         writel_relaxed(0, base + EXTI_RTSR);
 151
 152         pr_info("%s: %d External IRQs detected\n", node->full_name, nr_exti);
 153
 154         domain = irq_domain_add_linear(node, nr_exti,
 155                                        &irq_exti_domain_ops, NULL);
 156         if (!domain) {
 157                 pr_err("%s: Could not register interrupt domain.\n",
 158                                 node->name);
 159                 ret = -ENOMEM;
 160                 goto out_unmap;
 161         }
 162
 163         ret = irq_alloc_domain_generic_chips(domain, nr_exti, 1, "exti",
 164                                              handle_edge_irq, clr, 0, 0);
 165         if (ret) {
 166                 pr_err("%s: Could not allocate generic interrupt chip.\n",
 167                         node->full_name);
 168                 goto out_free_domain;
 169         }
 170
 171         gc = domain->gc->gc[0];
 172         gc->reg_base                         = base;
 173         gc->chip_types->type               = IRQ_TYPE_EDGE_BOTH;
 174         gc->chip_types->chip.name          = gc->chip_types[0].chip.name;
 175         gc->chip_types->chip.irq_ack       = irq_gc_ack_set_bit;
 176         gc->chip_types->chip.irq_mask      = irq_gc_mask_clr_bit;
 177         gc->chip_types->chip.irq_unmask    = irq_gc_mask_set_bit;
 178         gc->chip_types->chip.irq_set_type  = stm32_irq_set_type;
 179         gc->chip_types->chip.irq_set_wake  = stm32_irq_set_wake;
 180         gc->chip_types->regs.ack           = EXTI_PR;
 181         gc->chip_types->regs.mask          = EXTI_IMR;
 182         gc->chip_types->handler            = handle_edge_irq;
 183
 184         nr_irqs = of_irq_count(node);
 185         for (i = 0; i < nr_irqs; i++) {
 186                 unsigned int irq = irq_of_parse_and_map(node, i);
 187
 188                 irq_set_handler_data(irq, domain);
 189                 irq_set_chained_handler(irq, stm32_irq_handler);
 190         }
 191
 192         return 0;
 193
 194 out_free_domain:
 195         irq_domain_remove(domain);
 196 out_unmap:
 197         iounmap(base);
 198         return ret;
 199 }
 200
 201 IRQCHIP_DECLARE(stm32_exti, "st,stm32-exti", stm32_exti_init);