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 struct resource *mem_r; 155 void __iomem *mem; 156 spinlock_t *lock; /* memory lock */ 157 unsigned long val; 158 u32 clk_div; 159 160 mem_r = platform_get_resource(pdev, IORESOURCE_MEM, 0); 161 if (!mem_r) 162 return -EINVAL; 163 164 mem = devm_ioremap_resource(dev, mem_r); 165 if (IS_ERR(mem)) 166 return PTR_ERR(mem); 167 168 lock = devm_kzalloc(dev, sizeof(*lock), GFP_KERNEL); 169 if (!lock) 170 return -ENOMEM; 171 172 spin_lock_init(lock); 173 174 val = bcm6358_led_busy(mem); 175 val &= ~(BCM6358_SLED_POLARITY | BCM6358_SLED_CLKDIV_MASK); 176 if (of_property_read_bool(np, "brcm,clk-dat-low")) 177 val |= BCM6358_SLED_POLARITY; 178 of_property_read_u32(np, "brcm,clk-div", &clk_div); 179 switch (clk_div) { 180 case 8: 181 val |= BCM6358_SLED_CLKDIV_8; 182 break; 183 case 4: 184 val |= BCM6358_SLED_CLKDIV_4; 185 break; 186 case 2: 187 val |= BCM6358_SLED_CLKDIV_2; 188 break; 189 default: 190 val |= BCM6358_SLED_CLKDIV_1; 191 break; 192 } 193 bcm6358_led_write(mem + BCM6358_REG_CTRL, val); 194 195 for_each_available_child_of_node(np, child) { 196 int rc; 197 u32 reg; 198 199 if (of_property_read_u32(child, "reg", ®)) 200 continue; 201 202 if (reg >= BCM6358_SLED_MAX_COUNT) { 203 dev_err(dev, "invalid LED (%u >= %d)\n", reg, 204 BCM6358_SLED_MAX_COUNT); 205 continue; 206 } 207 208 rc = bcm6358_led(dev, child, reg, mem, lock); 209 if (rc < 0) { 210 of_node_put(child); 211 return rc; 212 } 213 } 214 215 return 0; 216 } 217 218 static const struct of_device_id bcm6358_leds_of_match[] = { 219 { .compatible = "brcm,bcm6358-leds", }, 220 { }, 221 }; 222 MODULE_DEVICE_TABLE(of, bcm6358_leds_of_match); 223 224 static struct platform_driver bcm6358_leds_driver = { 225 .probe = bcm6358_leds_probe, 226 .driver = { 227 .name = "leds-bcm6358", 228 .of_match_table = bcm6358_leds_of_match, 229 }, 230 }; 231 232 module_platform_driver(bcm6358_leds_driver); 233 234 MODULE_AUTHOR("Álvaro Fernández Rojas <noltari@gmail.com>"); 235 MODULE_DESCRIPTION("LED driver for BCM6358 controllers"); 236 MODULE_LICENSE("GPL v2"); 237 MODULE_ALIAS("platform:leds-bcm6358"); 238