drivers/clocksource/h8300_timer16.c

   1 /*
   2  *  H8/300 16bit Timer driver
   3  *
   4  *  Copyright 2015 Yoshinori Sato <ysato@users.sourcefoge.jp>
   5  */
   6
   7 #include <linux/errno.h>
   8 #include <linux/kernel.h>
   9 #include <linux/param.h>
  10 #include <linux/string.h>
  11 #include <linux/slab.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/init.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/clocksource.h>
  16 #include <linux/module.h>
  17 #include <linux/clk.h>
  18 #include <linux/io.h>
  19 #include <linux/of.h>
  20
  21 #include <asm/segment.h>
  22 #include <asm/irq.h>
  23
  24 #define TSTR    0
  25 #define TSNC    1
  26 #define TMDR    2
  27 #define TOLR    3
  28 #define TISRA   4
  29 #define TISRB   5
  30 #define TISRC   6
  31
  32 #define TCR     0
  33 #define TIOR    1
  34 #define TCNT    2
  35 #define GRA     4
  36 #define GRB     6
  37
  38 #define FLAG_REPROGRAM (1 << 0)
  39 #define FLAG_SKIPEVENT (1 << 1)
  40 #define FLAG_IRQCONTEXT (1 << 2)
  41 #define FLAG_STARTED (1 << 3)
  42
  43 #define ONESHOT  0
  44 #define PERIODIC 1
  45
  46 #define RELATIVE 0
  47 #define ABSOLUTE 1
  48
  49 struct timer16_priv {
  50         struct platform_device *pdev;
  51         struct clocksource cs;
  52         struct irqaction irqaction;
  53         unsigned long total_cycles;
  54         unsigned long mapbase;
  55         unsigned long mapcommon;
  56         unsigned long flags;
  57         unsigned short gra;
  58         unsigned short cs_enabled;
  59         unsigned char enb;
  60         unsigned char imfa;
  61         unsigned char imiea;
  62         unsigned char ovf;
  63         raw_spinlock_t lock;
  64         struct clk *clk;
  65 };
  66
  67 static unsigned long timer16_get_counter(struct timer16_priv *p)
  68 {
  69         unsigned long v1, v2, v3;
  70         int o1, o2;
  71
  72         o1 = ctrl_inb(p->mapcommon + TISRC) & p->ovf;
  73
  74         /* Make sure the timer value is stable. Stolen from acpi_pm.c */
  75         do {
  76                 o2 = o1;
  77                 v1 = ctrl_inw(p->mapbase + TCNT);
  78                 v2 = ctrl_inw(p->mapbase + TCNT);
  79                 v3 = ctrl_inw(p->mapbase + TCNT);
  80                 o1 = ctrl_inb(p->mapcommon + TISRC) & p->ovf;
  81         } while (unlikely((o1 != o2) || (v1 > v2 && v1 < v3)
  82                           || (v2 > v3 && v2 < v1) || (v3 > v1 && v3 < v2)));
  83
  84         v2 |= 0x10000;
  85         return v2;
  86 }
  87
  88
  89 static irqreturn_t timer16_interrupt(int irq, void *dev_id)
  90 {
  91         struct timer16_priv *p = (struct timer16_priv *)dev_id;
  92
  93         ctrl_outb(ctrl_inb(p->mapcommon + TISRA) & ~p->imfa,
  94                   p->mapcommon + TISRA);
  95         p->total_cycles += 0x10000;
  96
  97         return IRQ_HANDLED;
  98 }
  99
 100 static inline struct timer16_priv *cs_to_priv(struct clocksource *cs)
 101 {
 102         return container_of(cs, struct timer16_priv, cs);
 103 }
 104
 105 static cycle_t timer16_clocksource_read(struct clocksource *cs)
 106 {
 107         struct timer16_priv *p = cs_to_priv(cs);
 108         unsigned long flags, raw;
 109         unsigned long value;
 110
 111         raw_spin_lock_irqsave(&p->lock, flags);
 112         value = p->total_cycles;
 113         raw = timer16_get_counter(p);
 114         raw_spin_unlock_irqrestore(&p->lock, flags);
 115
 116         return value + raw;
 117 }
 118
 119 static int timer16_enable(struct clocksource *cs)
 120 {
 121         struct timer16_priv *p = cs_to_priv(cs);
 122
 123         WARN_ON(p->cs_enabled);
 124
 125         p->total_cycles = 0;
 126         ctrl_outw(0x0000, p->mapbase + TCNT);
 127         ctrl_outb(0x83, p->mapbase + TCR);
 128         ctrl_outb(ctrl_inb(p->mapcommon + TSTR) | p->enb,
 129                   p->mapcommon + TSTR);
 130
 131         p->cs_enabled = true;
 132         return 0;
 133 }
 134
 135 static void timer16_disable(struct clocksource *cs)
 136 {
 137         struct timer16_priv *p = cs_to_priv(cs);
 138
 139         WARN_ON(!p->cs_enabled);
 140
 141         ctrl_outb(ctrl_inb(p->mapcommon + TSTR) & ~p->enb,
 142                   p->mapcommon + TSTR);
 143
 144         p->cs_enabled = false;
 145 }
 146
 147 #define REG_CH   0
 148 #define REG_COMM 1
 149
 150 static int timer16_setup(struct timer16_priv *p, struct platform_device *pdev)
 151 {
 152         struct resource *res[2];
 153         int ret, irq;
 154         unsigned int ch;
 155
 156         p->pdev = pdev;
 157
 158         res[REG_CH] = platform_get_resource(p->pdev,
 159                                             IORESOURCE_MEM, REG_CH);
 160         res[REG_COMM] = platform_get_resource(p->pdev,
 161                                               IORESOURCE_MEM, REG_COMM);
 162         if (!res[REG_CH] || !res[REG_COMM]) {
 163                 dev_err(&p->pdev->dev, "failed to get I/O memory\n");
 164                 return -ENXIO;
 165         }
 166         irq = platform_get_irq(p->pdev, 0);
 167         if (irq < 0) {
 168                 dev_err(&p->pdev->dev, "failed to get irq\n");
 169                 return irq;
 170         }
 171
 172         p->clk = clk_get(&p->pdev->dev, "fck");
 173         if (IS_ERR(p->clk)) {
 174                 dev_err(&p->pdev->dev, "can't get clk\n");
 175                 return PTR_ERR(p->clk);
 176         }
 177         of_property_read_u32(p->pdev->dev.of_node, "renesas,channel", &ch);
 178
 179         p->pdev = pdev;
 180         p->mapbase = res[REG_CH]->start;
 181         p->mapcommon = res[REG_COMM]->start;
 182         p->enb = 1 << ch;
 183         p->imfa = 1 << ch;
 184         p->imiea = 1 << (4 + ch);
 185         p->cs.name = pdev->name;
 186         p->cs.rating = 200;
 187         p->cs.read = timer16_clocksource_read;
 188         p->cs.enable = timer16_enable;
 189         p->cs.disable = timer16_disable;
 190         p->cs.mask = CLOCKSOURCE_MASK(sizeof(unsigned long) * 8);
 191         p->cs.flags = CLOCK_SOURCE_IS_CONTINUOUS;
 192
 193         ret = request_irq(irq, timer16_interrupt,
 194                           IRQF_TIMER, pdev->name, p);
 195         if (ret < 0) {
 196                 dev_err(&p->pdev->dev, "failed to request irq %d\n", irq);
 197                 return ret;
 198         }
 199
 200         clocksource_register_hz(&p->cs, clk_get_rate(p->clk) / 8);
 201
 202         return 0;
 203 }
 204
 205 static int timer16_probe(struct platform_device *pdev)
 206 {
 207         struct timer16_priv *p = platform_get_drvdata(pdev);
 208
 209         if (p) {
 210                 dev_info(&pdev->dev, "kept as earlytimer\n");
 211                 return 0;
 212         }
 213
 214         p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL);
 215         if (!p)
 216                 return -ENOMEM;
 217
 218         return timer16_setup(p, pdev);
 219 }
 220
 221 static int timer16_remove(struct platform_device *pdev)
 222 {
 223         return -EBUSY;
 224 }
 225
 226 static const struct of_device_id timer16_of_table[] = {
 227         { .compatible = "renesas,16bit-timer" },
 228         { }
 229 };
 230 static struct platform_driver timer16_driver = {
 231         .probe          = timer16_probe,
 232         .remove         = timer16_remove,
 233         .driver         = {
 234                 .name   = "h8300h-16timer",
 235                 .of_match_table = of_match_ptr(timer16_of_table),
 236         }
 237 };
 238
 239 static int __init timer16_init(void)
 240 {
 241         return platform_driver_register(&timer16_driver);
 242 }
 243
 244 static void __exit timer16_exit(void)
 245 {
 246         platform_driver_unregister(&timer16_driver);
 247 }
 248
 249 subsys_initcall(timer16_init);
 250 module_exit(timer16_exit);
 251 MODULE_AUTHOR("Yoshinori Sato");
 252 MODULE_DESCRIPTION("H8/300H 16bit Timer Driver");
 253 MODULE_LICENSE("GPL v2");