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 enum led_default_state state; 100 unsigned long val; 101 int rc; 102 103 led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL); 104 if (!led) 105 return -ENOMEM; 106 107 led->pin = reg; 108 led->mem = mem; 109 led->lock = lock; 110 111 if (of_property_read_bool(nc, "active-low")) 112 led->active_low = true; 113 114 init_data.fwnode = of_fwnode_handle(nc); 115 116 state = led_init_default_state_get(init_data.fwnode); 117 switch (state) { 118 case LEDS_DEFSTATE_ON: 119 led->cdev.brightness = LED_FULL; 120 break; 121 case LEDS_DEFSTATE_KEEP: 122 val = bcm6358_led_read(led->mem + BCM6358_REG_MODE); 123 val &= BIT(led->pin); 124 if ((led->active_low && !val) || (!led->active_low && val)) 125 led->cdev.brightness = LED_FULL; 126 else 127 led->cdev.brightness = LED_OFF; 128 break; 129 default: 130 led->cdev.brightness = LED_OFF; 131 } 132 133 bcm6358_led_set(&led->cdev, led->cdev.brightness); 134 135 led->cdev.brightness_set = bcm6358_led_set; 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", ®)) 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"); 230