drivers/leds/leds-ns2.c

   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
  21 enum 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  */
  32 struct 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
  45 struct 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
  56 static 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
  76 static 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
  99 exit_unlock:
 100         write_unlock_irqrestore(&led->rw_lock, flags);
 101 }
 102
 103 static 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
 119 static 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
 126 static 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
 154 exit:
 155         return count;
 156 }
 157
 158 static 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
 167 static DEVICE_ATTR(sata, 0644, ns2_led_sata_show, ns2_led_sata_store);
 168
 169 static struct attribute *ns2_led_attrs[] = {
 170         &dev_attr_sata.attr,
 171         NULL
 172 };
 173 ATTRIBUTE_GROUPS(ns2_led);
 174
 175 static 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
 238 static 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
 265 static const struct of_device_id of_ns2_leds_match[] = {
 266         { .compatible = "lacie,ns2-leds", },
 267         {},
 268 };
 269 MODULE_DEVICE_TABLE(of, of_ns2_leds_match);
 270
 271 static 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
 279 module_platform_driver(ns2_led_driver);
 280
 281 MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>");
 282 MODULE_DESCRIPTION("Network Space v2 LED driver");
 283 MODULE_LICENSE("GPL");
 284 MODULE_ALIAS("platform:leds-ns2");