1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright 2008 4 * Guennadi Liakhovetski, DENX Software Engineering, <lg@denx.de> 5 * 6 * LED driver for the DAC124S085 SPI DAC 7 */ 8 9 #include <linux/leds.h> 10 #include <linux/module.h> 11 #include <linux/mutex.h> 12 #include <linux/slab.h> 13 #include <linux/spi/spi.h> 14 15 struct dac124s085_led { 16 struct led_classdev ldev; 17 struct spi_device *spi; 18 int id; 19 char name[sizeof("dac124s085-3")]; 20 21 struct mutex mutex; 22 }; 23 24 struct dac124s085 { 25 struct dac124s085_led leds[4]; 26 }; 27 28 #define REG_WRITE (0 << 12) 29 #define REG_WRITE_UPDATE (1 << 12) 30 #define ALL_WRITE_UPDATE (2 << 12) 31 #define POWER_DOWN_OUTPUT (3 << 12) 32 33 static int dac124s085_set_brightness(struct led_classdev *ldev, 34 enum led_brightness brightness) 35 { 36 struct dac124s085_led *led = container_of(ldev, struct dac124s085_led, 37 ldev); 38 u16 word; 39 int ret; 40 41 mutex_lock(&led->mutex); 42 word = cpu_to_le16(((led->id) << 14) | REG_WRITE_UPDATE | 43 (brightness & 0xfff)); 44 ret = spi_write(led->spi, (const u8 *)&word, sizeof(word)); 45 mutex_unlock(&led->mutex); 46 47 return ret; 48 } 49 50 static int dac124s085_probe(struct spi_device *spi) 51 { 52 struct dac124s085 *dac; 53 struct dac124s085_led *led; 54 int i, ret; 55 56 dac = devm_kzalloc(&spi->dev, sizeof(*dac), GFP_KERNEL); 57 if (!dac) 58 return -ENOMEM; 59 60 spi->bits_per_word = 16; 61 62 for (i = 0; i < ARRAY_SIZE(dac->leds); i++) { 63 led = dac->leds + i; 64 led->id = i; 65 led->spi = spi; 66 snprintf(led->name, sizeof(led->name), "dac124s085-%d", i); 67 mutex_init(&led->mutex); 68 led->ldev.name = led->name; 69 led->ldev.brightness = LED_OFF; 70 led->ldev.max_brightness = 0xfff; 71 led->ldev.brightness_set_blocking = dac124s085_set_brightness; 72 ret = led_classdev_register(&spi->dev, &led->ldev); 73 if (ret < 0) 74 goto eledcr; 75 } 76 77 spi_set_drvdata(spi, dac); 78 79 return 0; 80 81 eledcr: 82 while (i--) 83 led_classdev_unregister(&dac->leds[i].ldev); 84 85 return ret; 86 } 87 88 static int dac124s085_remove(struct spi_device *spi) 89 { 90 struct dac124s085 *dac = spi_get_drvdata(spi); 91 int i; 92 93 for (i = 0; i < ARRAY_SIZE(dac->leds); i++) 94 led_classdev_unregister(&dac->leds[i].ldev); 95 96 return 0; 97 } 98 99 static struct spi_driver dac124s085_driver = { 100 .probe = dac124s085_probe, 101 .remove = dac124s085_remove, 102 .driver = { 103 .name = "dac124s085", 104 }, 105 }; 106 107 module_spi_driver(dac124s085_driver); 108 109 MODULE_AUTHOR("Guennadi Liakhovetski <lg@denx.de>"); 110 MODULE_DESCRIPTION("DAC124S085 LED driver"); 111 MODULE_LICENSE("GPL v2"); 112 MODULE_ALIAS("spi:dac124s085"); 113