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 led_init_data init_data = {};
  98         struct bcm6358_led *led;
  99         const char *state;
 100         int rc;
 101
 102         led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
 103         if (!led)
 104                 return -ENOMEM;
 105
 106         led->pin = reg;
 107         led->mem = mem;
 108         led->lock = lock;
 109
 110         if (of_property_read_bool(nc, "active-low"))
 111                 led->active_low = true;
 112
 113         if (!of_property_read_string(nc, "default-state", &state)) {
 114                 if (!strcmp(state, "on")) {
 115                         led->cdev.brightness = LED_FULL;
 116                 } else if (!strcmp(state, "keep")) {
 117                         unsigned long val;
 118                         val = bcm6358_led_read(led->mem + BCM6358_REG_MODE);
 119                         val &= BIT(led->pin);
 120                         if ((led->active_low && !val) ||
 121                             (!led->active_low && val))
 122                                 led->cdev.brightness = LED_FULL;
 123                         else
 124                                 led->cdev.brightness = LED_OFF;
 125                 } else {
 126                         led->cdev.brightness = LED_OFF;
 127                 }
 128         } else {
 129                 led->cdev.brightness = LED_OFF;
 130         }
 131
 132         bcm6358_led_set(&led->cdev, led->cdev.brightness);
 133
 134         led->cdev.brightness_set = bcm6358_led_set;
 135         init_data.fwnode = of_fwnode_handle(nc);
 136
 137         rc = devm_led_classdev_register_ext(dev, &led->cdev, &init_data);
 138         if (rc < 0)
 139                 return rc;
 140
 141         dev_dbg(dev, "registered LED %s\n", led->cdev.name);
 142
 143         return 0;
 144 }
 145
 146 static int bcm6358_leds_probe(struct platform_device *pdev)
 147 {
 148         struct device *dev = &pdev->dev;
 149         struct device_node *np = dev_of_node(&pdev->dev);
 150         struct device_node *child;
 151         void __iomem *mem;
 152         spinlock_t *lock; /* memory lock */
 153         unsigned long val;
 154         u32 clk_div;
 155
 156         mem = devm_platform_ioremap_resource(pdev, 0);
 157         if (IS_ERR(mem))
 158                 return PTR_ERR(mem);
 159
 160         lock = devm_kzalloc(dev, sizeof(*lock), GFP_KERNEL);
 161         if (!lock)
 162                 return -ENOMEM;
 163
 164         spin_lock_init(lock);
 165
 166         val = bcm6358_led_busy(mem);
 167         val &= ~(BCM6358_SLED_POLARITY | BCM6358_SLED_CLKDIV_MASK);
 168         if (of_property_read_bool(np, "brcm,clk-dat-low"))
 169                 val |= BCM6358_SLED_POLARITY;
 170         of_property_read_u32(np, "brcm,clk-div", &clk_div);
 171         switch (clk_div) {
 172         case 8:
 173                 val |= BCM6358_SLED_CLKDIV_8;
 174                 break;
 175         case 4:
 176                 val |= BCM6358_SLED_CLKDIV_4;
 177                 break;
 178         case 2:
 179                 val |= BCM6358_SLED_CLKDIV_2;
 180                 break;
 181         default:
 182                 val |= BCM6358_SLED_CLKDIV_1;
 183                 break;
 184         }
 185         bcm6358_led_write(mem + BCM6358_REG_CTRL, val);
 186
 187         for_each_available_child_of_node(np, child) {
 188                 int rc;
 189                 u32 reg;
 190
 191                 if (of_property_read_u32(child, "reg", &reg))
 192                         continue;
 193
 194                 if (reg >= BCM6358_SLED_MAX_COUNT) {
 195                         dev_err(dev, "invalid LED (%u >= %d)\n", reg,
 196                                 BCM6358_SLED_MAX_COUNT);
 197                         continue;
 198                 }
 199
 200                 rc = bcm6358_led(dev, child, reg, mem, lock);
 201                 if (rc < 0) {
 202                         of_node_put(child);
 203                         return rc;
 204                 }
 205         }
 206
 207         return 0;
 208 }
 209
 210 static const struct of_device_id bcm6358_leds_of_match[] = {
 211         { .compatible = "brcm,bcm6358-leds", },
 212         { },
 213 };
 214 MODULE_DEVICE_TABLE(of, bcm6358_leds_of_match);
 215
 216 static struct platform_driver bcm6358_leds_driver = {
 217         .probe = bcm6358_leds_probe,
 218         .driver = {
 219                 .name = "leds-bcm6358",
 220                 .of_match_table = bcm6358_leds_of_match,
 221         },
 222 };
 223
 224 module_platform_driver(bcm6358_leds_driver);
 225
 226 MODULE_AUTHOR("Álvaro Fernández Rojas <noltari@gmail.com>");
 227 MODULE_DESCRIPTION("LED driver for BCM6358 controllers");
 228 MODULE_LICENSE("GPL v2");
 229 MODULE_ALIAS("platform:leds-bcm6358");