gateworks-gsc.c 6.8 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277
  1. // SPDX-License-Identifier: GPL-2.0
  2. /*
  3. * The Gateworks System Controller (GSC) is a multi-function
  4. * device designed for use in Gateworks Single Board Computers.
  5. * The control interface is I2C, with an interrupt. The device supports
  6. * system functions such as push-button monitoring, multiple ADC's for
  7. * voltage and temperature monitoring, fan controller and watchdog monitor.
  8. *
  9. * Copyright (C) 2020 Gateworks Corporation
  10. */
  11. #include <linux/device.h>
  12. #include <linux/i2c.h>
  13. #include <linux/interrupt.h>
  14. #include <linux/mfd/gsc.h>
  15. #include <linux/module.h>
  16. #include <linux/mutex.h>
  17. #include <linux/of.h>
  18. #include <linux/of_platform.h>
  19. #include <linux/platform_device.h>
  20. #include <linux/regmap.h>
  21. #include <asm/unaligned.h>
  22. /*
  23. * The GSC suffers from an errata where occasionally during
  24. * ADC cycles the chip can NAK I2C transactions. To ensure we have reliable
  25. * register access we place retries around register access.
  26. */
  27. #define I2C_RETRIES 3
  28. int gsc_write(void *context, unsigned int reg, unsigned int val)
  29. {
  30. struct i2c_client *client = context;
  31. int retry, ret;
  32. for (retry = 0; retry < I2C_RETRIES; retry++) {
  33. ret = i2c_smbus_write_byte_data(client, reg, val);
  34. /*
  35. * -EAGAIN returned when the i2c host controller is busy
  36. * -EIO returned when i2c device is busy
  37. */
  38. if (ret != -EAGAIN && ret != -EIO)
  39. break;
  40. }
  41. return 0;
  42. }
  43. EXPORT_SYMBOL_GPL(gsc_write);
  44. int gsc_read(void *context, unsigned int reg, unsigned int *val)
  45. {
  46. struct i2c_client *client = context;
  47. int retry, ret;
  48. for (retry = 0; retry < I2C_RETRIES; retry++) {
  49. ret = i2c_smbus_read_byte_data(client, reg);
  50. /*
  51. * -EAGAIN returned when the i2c host controller is busy
  52. * -EIO returned when i2c device is busy
  53. */
  54. if (ret != -EAGAIN && ret != -EIO)
  55. break;
  56. }
  57. *val = ret & 0xff;
  58. return 0;
  59. }
  60. EXPORT_SYMBOL_GPL(gsc_read);
  61. /*
  62. * gsc_powerdown - API to use GSC to power down board for a specific time
  63. *
  64. * secs - number of seconds to remain powered off
  65. */
  66. static int gsc_powerdown(struct gsc_dev *gsc, unsigned long secs)
  67. {
  68. int ret;
  69. unsigned char regs[4];
  70. dev_info(&gsc->i2c->dev, "GSC powerdown for %ld seconds\n",
  71. secs);
  72. put_unaligned_le32(secs, regs);
  73. ret = regmap_bulk_write(gsc->regmap, GSC_TIME_ADD, regs, 4);
  74. if (ret)
  75. return ret;
  76. ret = regmap_update_bits(gsc->regmap, GSC_CTRL_1,
  77. BIT(GSC_CTRL_1_SLEEP_ADD),
  78. BIT(GSC_CTRL_1_SLEEP_ADD));
  79. if (ret)
  80. return ret;
  81. ret = regmap_update_bits(gsc->regmap, GSC_CTRL_1,
  82. BIT(GSC_CTRL_1_SLEEP_ACTIVATE) |
  83. BIT(GSC_CTRL_1_SLEEP_ENABLE),
  84. BIT(GSC_CTRL_1_SLEEP_ACTIVATE) |
  85. BIT(GSC_CTRL_1_SLEEP_ENABLE));
  86. return ret;
  87. }
  88. static ssize_t gsc_show(struct device *dev, struct device_attribute *attr,
  89. char *buf)
  90. {
  91. struct gsc_dev *gsc = dev_get_drvdata(dev);
  92. const char *name = attr->attr.name;
  93. int rz = 0;
  94. if (strcasecmp(name, "fw_version") == 0)
  95. rz = sprintf(buf, "%d\n", gsc->fwver);
  96. else if (strcasecmp(name, "fw_crc") == 0)
  97. rz = sprintf(buf, "0x%04x\n", gsc->fwcrc);
  98. else
  99. dev_err(dev, "invalid command: '%s'\n", name);
  100. return rz;
  101. }
  102. static ssize_t gsc_store(struct device *dev, struct device_attribute *attr,
  103. const char *buf, size_t count)
  104. {
  105. struct gsc_dev *gsc = dev_get_drvdata(dev);
  106. const char *name = attr->attr.name;
  107. long value;
  108. if (strcasecmp(name, "powerdown") == 0) {
  109. if (kstrtol(buf, 0, &value) == 0)
  110. gsc_powerdown(gsc, value);
  111. } else {
  112. dev_err(dev, "invalid command: '%s\n", name);
  113. }
  114. return count;
  115. }
  116. static struct device_attribute attr_fwver =
  117. __ATTR(fw_version, 0440, gsc_show, NULL);
  118. static struct device_attribute attr_fwcrc =
  119. __ATTR(fw_crc, 0440, gsc_show, NULL);
  120. static struct device_attribute attr_pwrdown =
  121. __ATTR(powerdown, 0220, NULL, gsc_store);
  122. static struct attribute *gsc_attrs[] = {
  123. &attr_fwver.attr,
  124. &attr_fwcrc.attr,
  125. &attr_pwrdown.attr,
  126. NULL,
  127. };
  128. static struct attribute_group attr_group = {
  129. .attrs = gsc_attrs,
  130. };
  131. static const struct of_device_id gsc_of_match[] = {
  132. { .compatible = "gw,gsc", },
  133. { }
  134. };
  135. MODULE_DEVICE_TABLE(of, gsc_of_match);
  136. static struct regmap_bus gsc_regmap_bus = {
  137. .reg_read = gsc_read,
  138. .reg_write = gsc_write,
  139. };
  140. static const struct regmap_config gsc_regmap_config = {
  141. .reg_bits = 8,
  142. .val_bits = 8,
  143. .cache_type = REGCACHE_NONE,
  144. .max_register = GSC_WP,
  145. };
  146. static const struct regmap_irq gsc_irqs[] = {
  147. REGMAP_IRQ_REG(GSC_IRQ_PB, 0, BIT(GSC_IRQ_PB)),
  148. REGMAP_IRQ_REG(GSC_IRQ_KEY_ERASED, 0, BIT(GSC_IRQ_KEY_ERASED)),
  149. REGMAP_IRQ_REG(GSC_IRQ_EEPROM_WP, 0, BIT(GSC_IRQ_EEPROM_WP)),
  150. REGMAP_IRQ_REG(GSC_IRQ_RESV, 0, BIT(GSC_IRQ_RESV)),
  151. REGMAP_IRQ_REG(GSC_IRQ_GPIO, 0, BIT(GSC_IRQ_GPIO)),
  152. REGMAP_IRQ_REG(GSC_IRQ_TAMPER, 0, BIT(GSC_IRQ_TAMPER)),
  153. REGMAP_IRQ_REG(GSC_IRQ_WDT_TIMEOUT, 0, BIT(GSC_IRQ_WDT_TIMEOUT)),
  154. REGMAP_IRQ_REG(GSC_IRQ_SWITCH_HOLD, 0, BIT(GSC_IRQ_SWITCH_HOLD)),
  155. };
  156. static const struct regmap_irq_chip gsc_irq_chip = {
  157. .name = "gateworks-gsc",
  158. .irqs = gsc_irqs,
  159. .num_irqs = ARRAY_SIZE(gsc_irqs),
  160. .num_regs = 1,
  161. .status_base = GSC_IRQ_STATUS,
  162. .mask_base = GSC_IRQ_ENABLE,
  163. .mask_invert = true,
  164. .ack_base = GSC_IRQ_STATUS,
  165. .ack_invert = true,
  166. };
  167. static int gsc_probe(struct i2c_client *client)
  168. {
  169. struct device *dev = &client->dev;
  170. struct gsc_dev *gsc;
  171. struct regmap_irq_chip_data *irq_data;
  172. int ret;
  173. unsigned int reg;
  174. gsc = devm_kzalloc(dev, sizeof(*gsc), GFP_KERNEL);
  175. if (!gsc)
  176. return -ENOMEM;
  177. gsc->dev = &client->dev;
  178. gsc->i2c = client;
  179. i2c_set_clientdata(client, gsc);
  180. gsc->regmap = devm_regmap_init(dev, &gsc_regmap_bus, client,
  181. &gsc_regmap_config);
  182. if (IS_ERR(gsc->regmap))
  183. return PTR_ERR(gsc->regmap);
  184. if (regmap_read(gsc->regmap, GSC_FW_VER, &reg))
  185. return -EIO;
  186. gsc->fwver = reg;
  187. regmap_read(gsc->regmap, GSC_FW_CRC, &reg);
  188. gsc->fwcrc = reg;
  189. regmap_read(gsc->regmap, GSC_FW_CRC + 1, &reg);
  190. gsc->fwcrc |= reg << 8;
  191. gsc->i2c_hwmon = devm_i2c_new_dummy_device(dev, client->adapter,
  192. GSC_HWMON);
  193. if (IS_ERR(gsc->i2c_hwmon)) {
  194. dev_err(dev, "Failed to allocate I2C device for HWMON\n");
  195. return PTR_ERR(gsc->i2c_hwmon);
  196. }
  197. ret = devm_regmap_add_irq_chip(dev, gsc->regmap, client->irq,
  198. IRQF_ONESHOT | IRQF_SHARED |
  199. IRQF_TRIGGER_LOW, 0,
  200. &gsc_irq_chip, &irq_data);
  201. if (ret)
  202. return ret;
  203. dev_info(dev, "Gateworks System Controller v%d: fw 0x%04x\n",
  204. gsc->fwver, gsc->fwcrc);
  205. ret = sysfs_create_group(&dev->kobj, &attr_group);
  206. if (ret)
  207. dev_err(dev, "failed to create sysfs attrs\n");
  208. ret = devm_of_platform_populate(dev);
  209. if (ret) {
  210. sysfs_remove_group(&dev->kobj, &attr_group);
  211. return ret;
  212. }
  213. return 0;
  214. }
  215. static int gsc_remove(struct i2c_client *client)
  216. {
  217. sysfs_remove_group(&client->dev.kobj, &attr_group);
  218. return 0;
  219. }
  220. static struct i2c_driver gsc_driver = {
  221. .driver = {
  222. .name = "gateworks-gsc",
  223. .of_match_table = gsc_of_match,
  224. },
  225. .probe_new = gsc_probe,
  226. .remove = gsc_remove,
  227. };
  228. module_i2c_driver(gsc_driver);
  229. MODULE_AUTHOR("Tim Harvey <tharvey@gateworks.com>");
  230. MODULE_DESCRIPTION("I2C Core interface for GSC");
  231. MODULE_LICENSE("GPL v2");