leds-bcm6358.c (5340B)
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 */ 38struct 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 46static 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 55static 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 64static 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 75static 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 94static 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 146static 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 210static const struct of_device_id bcm6358_leds_of_match[] = { 211 { .compatible = "brcm,bcm6358-leds", }, 212 { }, 213}; 214MODULE_DEVICE_TABLE(of, bcm6358_leds_of_match); 215 216static 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 224module_platform_driver(bcm6358_leds_driver); 225 226MODULE_AUTHOR("Álvaro Fernández Rojas <noltari@gmail.com>"); 227MODULE_DESCRIPTION("LED driver for BCM6358 controllers"); 228MODULE_LICENSE("GPL v2"); 229MODULE_ALIAS("platform:leds-bcm6358");