linux/drivers/leds/leds-ns2.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * leds-ns2.c - Driver for the Network Space v2 (and parents) dual-GPIO LED
   4 *
   5 * Copyright (C) 2010 LaCie
   6 *
   7 * Author: Simon Guinot <sguinot@lacie.com>
   8 *
   9 * Based on leds-gpio.c by Raphael Assenat <raph@8d.com>
  10 */
  11
  12#include <linux/kernel.h>
  13#include <linux/platform_device.h>
  14#include <linux/slab.h>
  15#include <linux/gpio/consumer.h>
  16#include <linux/leds.h>
  17#include <linux/module.h>
  18#include <linux/of.h>
  19#include "leds.h"
  20
  21enum ns2_led_modes {
  22        NS_V2_LED_OFF,
  23        NS_V2_LED_ON,
  24        NS_V2_LED_SATA,
  25};
  26
  27/*
  28 * If the size of this structure or types of its members is changed,
  29 * the filling of array modval in function ns2_led_register must be changed
  30 * accordingly.
  31 */
  32struct ns2_led_modval {
  33        u32                     mode;
  34        u32                     cmd_level;
  35        u32                     slow_level;
  36} __packed;
  37
  38/*
  39 * The Network Space v2 dual-GPIO LED is wired to a CPLD. Three different LED
  40 * modes are available: off, on and SATA activity blinking. The LED modes are
  41 * controlled through two GPIOs (command and slow): each combination of values
  42 * for the command/slow GPIOs corresponds to a LED mode.
  43 */
  44
  45struct ns2_led {
  46        struct led_classdev     cdev;
  47        struct gpio_desc        *cmd;
  48        struct gpio_desc        *slow;
  49        bool                    can_sleep;
  50        unsigned char           sata; /* True when SATA mode active. */
  51        rwlock_t                rw_lock; /* Lock GPIOs. */
  52        int                     num_modes;
  53        struct ns2_led_modval   *modval;
  54};
  55
  56static int ns2_led_get_mode(struct ns2_led *led, enum ns2_led_modes *mode)
  57{
  58        int i;
  59        int cmd_level;
  60        int slow_level;
  61
  62        cmd_level = gpiod_get_value_cansleep(led->cmd);
  63        slow_level = gpiod_get_value_cansleep(led->slow);
  64
  65        for (i = 0; i < led->num_modes; i++) {
  66                if (cmd_level == led->modval[i].cmd_level &&
  67                    slow_level == led->modval[i].slow_level) {
  68                        *mode = led->modval[i].mode;
  69                        return 0;
  70                }
  71        }
  72
  73        return -EINVAL;
  74}
  75
  76static void ns2_led_set_mode(struct ns2_led *led, enum ns2_led_modes mode)
  77{
  78        int i;
  79        unsigned long flags;
  80
  81        for (i = 0; i < led->num_modes; i++)
  82                if (mode == led->modval[i].mode)
  83                        break;
  84
  85        if (i == led->num_modes)
  86                return;
  87
  88        write_lock_irqsave(&led->rw_lock, flags);
  89
  90        if (!led->can_sleep) {
  91                gpiod_set_value(led->cmd, led->modval[i].cmd_level);
  92                gpiod_set_value(led->slow, led->modval[i].slow_level);
  93                goto exit_unlock;
  94        }
  95
  96        gpiod_set_value_cansleep(led->cmd, led->modval[i].cmd_level);
  97        gpiod_set_value_cansleep(led->slow, led->modval[i].slow_level);
  98
  99exit_unlock:
 100        write_unlock_irqrestore(&led->rw_lock, flags);
 101}
 102
 103static void ns2_led_set(struct led_classdev *led_cdev,
 104                        enum led_brightness value)
 105{
 106        struct ns2_led *led = container_of(led_cdev, struct ns2_led, cdev);
 107        enum ns2_led_modes mode;
 108
 109        if (value == LED_OFF)
 110                mode = NS_V2_LED_OFF;
 111        else if (led->sata)
 112                mode = NS_V2_LED_SATA;
 113        else
 114                mode = NS_V2_LED_ON;
 115
 116        ns2_led_set_mode(led, mode);
 117}
 118
 119static int ns2_led_set_blocking(struct led_classdev *led_cdev,
 120                        enum led_brightness value)
 121{
 122        ns2_led_set(led_cdev, value);
 123        return 0;
 124}
 125
 126static ssize_t ns2_led_sata_store(struct device *dev,
 127                                  struct device_attribute *attr,
 128                                  const char *buff, size_t count)
 129{
 130        struct led_classdev *led_cdev = dev_get_drvdata(dev);
 131        struct ns2_led *led = container_of(led_cdev, struct ns2_led, cdev);
 132        int ret;
 133        unsigned long enable;
 134
 135        ret = kstrtoul(buff, 10, &enable);
 136        if (ret < 0)
 137                return ret;
 138
 139        enable = !!enable;
 140
 141        if (led->sata == enable)
 142                goto exit;
 143
 144        led->sata = enable;
 145
 146        if (!led_get_brightness(led_cdev))
 147                goto exit;
 148
 149        if (enable)
 150                ns2_led_set_mode(led, NS_V2_LED_SATA);
 151        else
 152                ns2_led_set_mode(led, NS_V2_LED_ON);
 153
 154exit:
 155        return count;
 156}
 157
 158static ssize_t ns2_led_sata_show(struct device *dev,
 159                                 struct device_attribute *attr, char *buf)
 160{
 161        struct led_classdev *led_cdev = dev_get_drvdata(dev);
 162        struct ns2_led *led = container_of(led_cdev, struct ns2_led, cdev);
 163
 164        return sprintf(buf, "%d\n", led->sata);
 165}
 166
 167static DEVICE_ATTR(sata, 0644, ns2_led_sata_show, ns2_led_sata_store);
 168
 169static struct attribute *ns2_led_attrs[] = {
 170        &dev_attr_sata.attr,
 171        NULL
 172};
 173ATTRIBUTE_GROUPS(ns2_led);
 174
 175static int ns2_led_register(struct device *dev, struct fwnode_handle *node,
 176                            struct ns2_led *led)
 177{
 178        struct led_init_data init_data = {};
 179        struct ns2_led_modval *modval;
 180        enum ns2_led_modes mode;
 181        int nmodes, ret;
 182
 183        led->cmd = devm_fwnode_gpiod_get_index(dev, node, "cmd", 0, GPIOD_ASIS,
 184                                               fwnode_get_name(node));
 185        if (IS_ERR(led->cmd))
 186                return PTR_ERR(led->cmd);
 187
 188        led->slow = devm_fwnode_gpiod_get_index(dev, node, "slow", 0,
 189                                                GPIOD_ASIS,
 190                                                fwnode_get_name(node));
 191        if (IS_ERR(led->slow))
 192                return PTR_ERR(led->slow);
 193
 194        ret = fwnode_property_count_u32(node, "modes-map");
 195        if (ret < 0 || ret % 3) {
 196                dev_err(dev, "Missing or malformed modes-map for %pfw\n", node);
 197                return -EINVAL;
 198        }
 199
 200        nmodes = ret / 3;
 201        modval = devm_kcalloc(dev, nmodes, sizeof(*modval), GFP_KERNEL);
 202        if (!modval)
 203                return -ENOMEM;
 204
 205        fwnode_property_read_u32_array(node, "modes-map", (void *)modval,
 206                                       nmodes * 3);
 207
 208        rwlock_init(&led->rw_lock);
 209
 210        led->cdev.blink_set = NULL;
 211        led->cdev.flags |= LED_CORE_SUSPENDRESUME;
 212        led->cdev.groups = ns2_led_groups;
 213        led->can_sleep = gpiod_cansleep(led->cmd) || gpiod_cansleep(led->slow);
 214        if (led->can_sleep)
 215                led->cdev.brightness_set_blocking = ns2_led_set_blocking;
 216        else
 217                led->cdev.brightness_set = ns2_led_set;
 218        led->num_modes = nmodes;
 219        led->modval = modval;
 220
 221        ret = ns2_led_get_mode(led, &mode);
 222        if (ret < 0)
 223                return ret;
 224
 225        /* Set LED initial state. */
 226        led->sata = (mode == NS_V2_LED_SATA) ? 1 : 0;
 227        led->cdev.brightness = (mode == NS_V2_LED_OFF) ? LED_OFF : LED_FULL;
 228
 229        init_data.fwnode = node;
 230
 231        ret = devm_led_classdev_register_ext(dev, &led->cdev, &init_data);
 232        if (ret)
 233                dev_err(dev, "Failed to register LED for node %pfw\n", node);
 234
 235        return ret;
 236}
 237
 238static int ns2_led_probe(struct platform_device *pdev)
 239{
 240        struct device *dev = &pdev->dev;
 241        struct fwnode_handle *child;
 242        struct ns2_led *leds;
 243        int count;
 244        int ret;
 245
 246        count = device_get_child_node_count(dev);
 247        if (!count)
 248                return -ENODEV;
 249
 250        leds = devm_kzalloc(dev, array_size(sizeof(*leds), count), GFP_KERNEL);
 251        if (!leds)
 252                return -ENOMEM;
 253
 254        device_for_each_child_node(dev, child) {
 255                ret = ns2_led_register(dev, child, leds++);
 256                if (ret) {
 257                        fwnode_handle_put(child);
 258                        return ret;
 259                }
 260        }
 261
 262        return 0;
 263}
 264
 265static const struct of_device_id of_ns2_leds_match[] = {
 266        { .compatible = "lacie,ns2-leds", },
 267        {},
 268};
 269MODULE_DEVICE_TABLE(of, of_ns2_leds_match);
 270
 271static struct platform_driver ns2_led_driver = {
 272        .probe          = ns2_led_probe,
 273        .driver         = {
 274                .name           = "leds-ns2",
 275                .of_match_table = of_ns2_leds_match,
 276        },
 277};
 278
 279module_platform_driver(ns2_led_driver);
 280
 281MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>");
 282MODULE_DESCRIPTION("Network Space v2 LED driver");
 283MODULE_LICENSE("GPL");
 284MODULE_ALIAS("platform:leds-ns2");
 285