arch/arm/plat-omap/debug-leds.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * linux/arch/arm/plat-omap/debug-leds.c
   4  *
   5  * Copyright 2011 by Bryan Wu <bryan.wu@canonical.com>
   6  * Copyright 2003 by Texas Instruments Incorporated
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/init.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/leds.h>
  13 #include <linux/io.h>
  14 #include <linux/platform_data/gpio-omap.h>
  15 #include <linux/slab.h>
  16
  17 #include <asm/mach-types.h>
  18
  19 /* Many OMAP development platforms reuse the same "debug board"; these
  20  * platforms include H2, H3, H4, and Perseus2.  There are 16 LEDs on the
  21  * debug board (all green), accessed through FPGA registers.
  22  */
  23
  24 /* NOTE:  most boards don't have a static mapping for the FPGA ... */
  25 struct h2p2_dbg_fpga {
  26         /* offset 0x00 */
  27         u16             smc91x[8];
  28         /* offset 0x10 */
  29         u16             fpga_rev;
  30         u16             board_rev;
  31         u16             gpio_outputs;
  32         u16             leds;
  33         /* offset 0x18 */
  34         u16             misc_inputs;
  35         u16             lan_status;
  36         u16             lan_reset;
  37         u16             reserved0;
  38         /* offset 0x20 */
  39         u16             ps2_data;
  40         u16             ps2_ctrl;
  41         /* plus also 4 rs232 ports ... */
  42 };
  43
  44 static struct h2p2_dbg_fpga __iomem *fpga;
  45
  46 static u16 fpga_led_state;
  47
  48 struct dbg_led {
  49         struct led_classdev     cdev;
  50         u16                     mask;
  51 };
  52
  53 static const struct {
  54         const char *name;
  55         const char *trigger;
  56 } dbg_leds[] = {
  57         { "dbg:d4", "heartbeat", },
  58         { "dbg:d5", "cpu0", },
  59         { "dbg:d6", "default-on", },
  60         { "dbg:d7", },
  61         { "dbg:d8", },
  62         { "dbg:d9", },
  63         { "dbg:d10", },
  64         { "dbg:d11", },
  65         { "dbg:d12", },
  66         { "dbg:d13", },
  67         { "dbg:d14", },
  68         { "dbg:d15", },
  69         { "dbg:d16", },
  70         { "dbg:d17", },
  71         { "dbg:d18", },
  72         { "dbg:d19", },
  73 };
  74
  75 /*
  76  * The triggers lines up below will only be used if the
  77  * LED triggers are compiled in.
  78  */
  79 static void dbg_led_set(struct led_classdev *cdev,
  80                               enum led_brightness b)
  81 {
  82         struct dbg_led *led = container_of(cdev, struct dbg_led, cdev);
  83         u16 reg;
  84
  85         reg = readw_relaxed(&fpga->leds);
  86         if (b != LED_OFF)
  87                 reg |= led->mask;
  88         else
  89                 reg &= ~led->mask;
  90         writew_relaxed(reg, &fpga->leds);
  91 }
  92
  93 static enum led_brightness dbg_led_get(struct led_classdev *cdev)
  94 {
  95         struct dbg_led *led = container_of(cdev, struct dbg_led, cdev);
  96         u16 reg;
  97
  98         reg = readw_relaxed(&fpga->leds);
  99         return (reg & led->mask) ? LED_FULL : LED_OFF;
 100 }
 101
 102 static int fpga_probe(struct platform_device *pdev)
 103 {
 104         struct resource *iomem;
 105         int i;
 106
 107         iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 108         if (!iomem)
 109                 return -ENODEV;
 110
 111         fpga = ioremap(iomem->start, resource_size(iomem));
 112         writew_relaxed(0xff, &fpga->leds);
 113
 114         for (i = 0; i < ARRAY_SIZE(dbg_leds); i++) {
 115                 struct dbg_led *led;
 116
 117                 led = kzalloc(sizeof(*led), GFP_KERNEL);
 118                 if (!led)
 119                         break;
 120
 121                 led->cdev.name = dbg_leds[i].name;
 122                 led->cdev.brightness_set = dbg_led_set;
 123                 led->cdev.brightness_get = dbg_led_get;
 124                 led->cdev.default_trigger = dbg_leds[i].trigger;
 125                 led->mask = BIT(i);
 126
 127                 if (led_classdev_register(NULL, &led->cdev) < 0) {
 128                         kfree(led);
 129                         break;
 130                 }
 131         }
 132
 133         return 0;
 134 }
 135
 136 static int fpga_suspend_noirq(struct device *dev)
 137 {
 138         fpga_led_state = readw_relaxed(&fpga->leds);
 139         writew_relaxed(0xff, &fpga->leds);
 140
 141         return 0;
 142 }
 143
 144 static int fpga_resume_noirq(struct device *dev)
 145 {
 146         writew_relaxed(~fpga_led_state, &fpga->leds);
 147         return 0;
 148 }
 149
 150 static const struct dev_pm_ops fpga_dev_pm_ops = {
 151         .suspend_noirq = fpga_suspend_noirq,
 152         .resume_noirq = fpga_resume_noirq,
 153 };
 154
 155 static struct platform_driver led_driver = {
 156         .driver.name    = "omap_dbg_led",
 157         .driver.pm      = &fpga_dev_pm_ops,
 158         .probe          = fpga_probe,
 159 };
 160
 161 static int __init fpga_init(void)
 162 {
 163         if (machine_is_omap_h4()
 164                         || machine_is_omap_h3()
 165                         || machine_is_omap_h2()
 166                         || machine_is_omap_perseus2()
 167                         )
 168                 return platform_driver_register(&led_driver);
 169         return 0;
 170 }
 171 fs_initcall(fpga_init);