drivers/leds/leds-bcm6358.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Driver for BCM6358 memory-mapped LEDs, based on leds-syscon.c
   4  *
   5  * Copyright 2015 Álvaro Fernández Rojas <noltari@gmail.com>
   6  */
   7 #include <linux/delay.h>
   8 #include <linux/io.h>
   9 #include <linux/leds.h>
  10 #include <linux/module.h>
  11 #include <linux/of.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/spinlock.h>
  14
  15 #define BCM6358_REG_MODE                0x0
  16 #define BCM6358_REG_CTRL                0x4
  17
  18 #define BCM6358_SLED_CLKDIV_MASK        3
  19 #define BCM6358_SLED_CLKDIV_1           0
  20 #define BCM6358_SLED_CLKDIV_2           1
  21 #define BCM6358_SLED_CLKDIV_4           2
  22 #define BCM6358_SLED_CLKDIV_8           3
  23
  24 #define BCM6358_SLED_POLARITY           BIT(2)
  25 #define BCM6358_SLED_BUSY               BIT(3)
  26
  27 #define BCM6358_SLED_MAX_COUNT          32
  28 #define BCM6358_SLED_WAIT               100
  29
  30 /**
  31  * struct bcm6358_led - state container for bcm6358 based LEDs
  32  * @cdev: LED class device for this LED
  33  * @mem: memory resource
  34  * @lock: memory lock
  35  * @pin: LED pin number
  36  * @active_low: LED is active low
  37  */
  38 struct bcm6358_led {
  39         struct led_classdev cdev;
  40         void __iomem *mem;
  41         spinlock_t *lock;
  42         unsigned long pin;
  43         bool active_low;
  44 };
  45
  46 static void bcm6358_led_write(void __iomem *reg, unsigned long data)
  47 {
  48 #ifdef CONFIG_CPU_BIG_ENDIAN
  49         iowrite32be(data, reg);
  50 #else
  51         writel(data, reg);
  52 #endif
  53 }
  54
  55 static unsigned long bcm6358_led_read(void __iomem *reg)
  56 {
  57 #ifdef CONFIG_CPU_BIG_ENDIAN
  58         return ioread32be(reg);
  59 #else
  60         return readl(reg);
  61 #endif
  62 }
  63
  64 static unsigned long bcm6358_led_busy(void __iomem *mem)
  65 {
  66         unsigned long val;
  67
  68         while ((val = bcm6358_led_read(mem + BCM6358_REG_CTRL)) &
  69                 BCM6358_SLED_BUSY)
  70                 udelay(BCM6358_SLED_WAIT);
  71
  72         return val;
  73 }
  74
  75 static void bcm6358_led_set(struct led_classdev *led_cdev,
  76                             enum led_brightness value)
  77 {
  78         struct bcm6358_led *led =
  79                 container_of(led_cdev, struct bcm6358_led, cdev);
  80         unsigned long flags, val;
  81
  82         spin_lock_irqsave(led->lock, flags);
  83         bcm6358_led_busy(led->mem);
  84         val = bcm6358_led_read(led->mem + BCM6358_REG_MODE);
  85         if ((led->active_low && value == LED_OFF) ||
  86             (!led->active_low && value != LED_OFF))
  87                 val |= BIT(led->pin);
  88         else
  89                 val &= ~(BIT(led->pin));
  90         bcm6358_led_write(led->mem + BCM6358_REG_MODE, val);
  91         spin_unlock_irqrestore(led->lock, flags);
  92 }
  93
  94 static int bcm6358_led(struct device *dev, struct device_node *nc, u32 reg,
  95                        void __iomem *mem, spinlock_t *lock)
  96 {
  97         struct bcm6358_led *led;
  98         const char *state;
  99         int rc;
 100
 101         led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
 102         if (!led)
 103                 return -ENOMEM;
 104
 105         led->pin = reg;
 106         led->mem = mem;
 107         led->lock = lock;
 108
 109         if (of_property_read_bool(nc, "active-low"))
 110                 led->active_low = true;
 111
 112         led->cdev.name = of_get_property(nc, "label", NULL) ? : nc->name;
 113         led->cdev.default_trigger = of_get_property(nc,
 114                                                     "linux,default-trigger",
 115                                                     NULL);
 116
 117         if (!of_property_read_string(nc, "default-state", &state)) {
 118                 if (!strcmp(state, "on")) {
 119                         led->cdev.brightness = LED_FULL;
 120                 } else if (!strcmp(state, "keep")) {
 121                         unsigned long val;
 122                         val = bcm6358_led_read(led->mem + BCM6358_REG_MODE);
 123                         val &= BIT(led->pin);
 124                         if ((led->active_low && !val) ||
 125                             (!led->active_low && val))
 126                                 led->cdev.brightness = LED_FULL;
 127                         else
 128                                 led->cdev.brightness = LED_OFF;
 129                 } else {
 130                         led->cdev.brightness = LED_OFF;
 131                 }
 132         } else {
 133                 led->cdev.brightness = LED_OFF;
 134         }
 135
 136         bcm6358_led_set(&led->cdev, led->cdev.brightness);
 137
 138         led->cdev.brightness_set = bcm6358_led_set;
 139
 140         rc = led_classdev_register(dev, &led->cdev);
 141         if (rc < 0)
 142                 return rc;
 143
 144         dev_dbg(dev, "registered LED %s\n", led->cdev.name);
 145
 146         return 0;
 147 }
 148
 149 static int bcm6358_leds_probe(struct platform_device *pdev)
 150 {
 151         struct device *dev = &pdev->dev;
 152         struct device_node *np = pdev->dev.of_node;
 153         struct device_node *child;
 154         void __iomem *mem;
 155         spinlock_t *lock; /* memory lock */
 156         unsigned long val;
 157         u32 clk_div;
 158
 159         mem = devm_platform_ioremap_resource(pdev, 0);
 160         if (IS_ERR(mem))
 161                 return PTR_ERR(mem);
 162
 163         lock = devm_kzalloc(dev, sizeof(*lock), GFP_KERNEL);
 164         if (!lock)
 165                 return -ENOMEM;
 166
 167         spin_lock_init(lock);
 168
 169         val = bcm6358_led_busy(mem);
 170         val &= ~(BCM6358_SLED_POLARITY | BCM6358_SLED_CLKDIV_MASK);
 171         if (of_property_read_bool(np, "brcm,clk-dat-low"))
 172                 val |= BCM6358_SLED_POLARITY;
 173         of_property_read_u32(np, "brcm,clk-div", &clk_div);
 174         switch (clk_div) {
 175         case 8:
 176                 val |= BCM6358_SLED_CLKDIV_8;
 177                 break;
 178         case 4:
 179                 val |= BCM6358_SLED_CLKDIV_4;
 180                 break;
 181         case 2:
 182                 val |= BCM6358_SLED_CLKDIV_2;
 183                 break;
 184         default:
 185                 val |= BCM6358_SLED_CLKDIV_1;
 186                 break;
 187         }
 188         bcm6358_led_write(mem + BCM6358_REG_CTRL, val);
 189
 190         for_each_available_child_of_node(np, child) {
 191                 int rc;
 192                 u32 reg;
 193
 194                 if (of_property_read_u32(child, "reg", &reg))
 195                         continue;
 196
 197                 if (reg >= BCM6358_SLED_MAX_COUNT) {
 198                         dev_err(dev, "invalid LED (%u >= %d)\n", reg,
 199                                 BCM6358_SLED_MAX_COUNT);
 200                         continue;
 201                 }
 202
 203                 rc = bcm6358_led(dev, child, reg, mem, lock);
 204                 if (rc < 0) {
 205                         of_node_put(child);
 206                         return rc;
 207                 }
 208         }
 209
 210         return 0;
 211 }
 212
 213 static const struct of_device_id bcm6358_leds_of_match[] = {
 214         { .compatible = "brcm,bcm6358-leds", },
 215         { },
 216 };
 217 MODULE_DEVICE_TABLE(of, bcm6358_leds_of_match);
 218
 219 static struct platform_driver bcm6358_leds_driver = {
 220         .probe = bcm6358_leds_probe,
 221         .driver = {
 222                 .name = "leds-bcm6358",
 223                 .of_match_table = bcm6358_leds_of_match,
 224         },
 225 };
 226
 227 module_platform_driver(bcm6358_leds_driver);
 228
 229 MODULE_AUTHOR("Álvaro Fernández Rojas <noltari@gmail.com>");
 230 MODULE_DESCRIPTION("LED driver for BCM6358 controllers");
 231 MODULE_LICENSE("GPL v2");
 232 MODULE_ALIAS("platform:leds-bcm6358");