max1111.c 6.8 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * max1111.c - +2.7V, Low-Power, Multichannel, Serial 8-bit ADCs
  4. *
  5. * Based on arch/arm/mach-pxa/corgi_ssp.c
  6. *
  7. * Copyright (C) 2004-2005 Richard Purdie
  8. *
  9. * Copyright (C) 2008 Marvell International Ltd.
  10. * Eric Miao <[email protected]>
  11. */
  12. #include <linux/module.h>
  13. #include <linux/kernel.h>
  14. #include <linux/init.h>
  15. #include <linux/err.h>
  16. #include <linux/hwmon.h>
  17. #include <linux/hwmon-sysfs.h>
  18. #include <linux/spi/spi.h>
  19. #include <linux/slab.h>
  20. enum chips { max1110, max1111, max1112, max1113 };
  21. #define MAX1111_TX_BUF_SIZE 1
  22. #define MAX1111_RX_BUF_SIZE 2
  23. /* MAX1111 Commands */
  24. #define MAX1111_CTRL_PD0 (1u << 0)
  25. #define MAX1111_CTRL_PD1 (1u << 1)
  26. #define MAX1111_CTRL_SGL (1u << 2)
  27. #define MAX1111_CTRL_UNI (1u << 3)
  28. #define MAX1110_CTRL_SEL_SH (4)
  29. #define MAX1111_CTRL_SEL_SH (5) /* NOTE: bit 4 is ignored */
  30. #define MAX1111_CTRL_STR (1u << 7)
  31. struct max1111_data {
  32. struct spi_device *spi;
  33. struct device *hwmon_dev;
  34. struct spi_message msg;
  35. struct spi_transfer xfer[2];
  36. uint8_t tx_buf[MAX1111_TX_BUF_SIZE];
  37. uint8_t rx_buf[MAX1111_RX_BUF_SIZE];
  38. struct mutex drvdata_lock;
  39. /* protect msg, xfer and buffers from multiple access */
  40. int sel_sh;
  41. int lsb;
  42. };
  43. static int max1111_read(struct device *dev, int channel)
  44. {
  45. struct max1111_data *data = dev_get_drvdata(dev);
  46. uint8_t v1, v2;
  47. int err;
  48. /* writing to drvdata struct is not thread safe, wait on mutex */
  49. mutex_lock(&data->drvdata_lock);
  50. data->tx_buf[0] = (channel << data->sel_sh) |
  51. MAX1111_CTRL_PD0 | MAX1111_CTRL_PD1 |
  52. MAX1111_CTRL_SGL | MAX1111_CTRL_UNI | MAX1111_CTRL_STR;
  53. err = spi_sync(data->spi, &data->msg);
  54. if (err < 0) {
  55. dev_err(dev, "spi_sync failed with %d\n", err);
  56. mutex_unlock(&data->drvdata_lock);
  57. return err;
  58. }
  59. v1 = data->rx_buf[0];
  60. v2 = data->rx_buf[1];
  61. mutex_unlock(&data->drvdata_lock);
  62. if ((v1 & 0xc0) || (v2 & 0x3f))
  63. return -EINVAL;
  64. return (v1 << 2) | (v2 >> 6);
  65. }
  66. #ifdef CONFIG_SHARPSL_PM
  67. static struct max1111_data *the_max1111;
  68. int max1111_read_channel(int channel)
  69. {
  70. if (!the_max1111 || !the_max1111->spi)
  71. return -ENODEV;
  72. return max1111_read(&the_max1111->spi->dev, channel);
  73. }
  74. EXPORT_SYMBOL(max1111_read_channel);
  75. #endif
  76. /*
  77. * NOTE: SPI devices do not have a default 'name' attribute, which is
  78. * likely to be used by hwmon applications to distinguish between
  79. * different devices, explicitly add a name attribute here.
  80. */
  81. static ssize_t name_show(struct device *dev,
  82. struct device_attribute *attr, char *buf)
  83. {
  84. return sprintf(buf, "%s\n", to_spi_device(dev)->modalias);
  85. }
  86. static ssize_t show_adc(struct device *dev,
  87. struct device_attribute *attr, char *buf)
  88. {
  89. struct max1111_data *data = dev_get_drvdata(dev);
  90. int channel = to_sensor_dev_attr(attr)->index;
  91. int ret;
  92. ret = max1111_read(dev, channel);
  93. if (ret < 0)
  94. return ret;
  95. /*
  96. * Assume the reference voltage to be 2.048V or 4.096V, with an 8-bit
  97. * sample. The LSB weight is 8mV or 16mV depending on the chip type.
  98. */
  99. return sprintf(buf, "%d\n", ret * data->lsb);
  100. }
  101. #define MAX1111_ADC_ATTR(_id) \
  102. SENSOR_DEVICE_ATTR(in##_id##_input, S_IRUGO, show_adc, NULL, _id)
  103. static DEVICE_ATTR_RO(name);
  104. static MAX1111_ADC_ATTR(0);
  105. static MAX1111_ADC_ATTR(1);
  106. static MAX1111_ADC_ATTR(2);
  107. static MAX1111_ADC_ATTR(3);
  108. static MAX1111_ADC_ATTR(4);
  109. static MAX1111_ADC_ATTR(5);
  110. static MAX1111_ADC_ATTR(6);
  111. static MAX1111_ADC_ATTR(7);
  112. static struct attribute *max1111_attributes[] = {
  113. &dev_attr_name.attr,
  114. &sensor_dev_attr_in0_input.dev_attr.attr,
  115. &sensor_dev_attr_in1_input.dev_attr.attr,
  116. &sensor_dev_attr_in2_input.dev_attr.attr,
  117. &sensor_dev_attr_in3_input.dev_attr.attr,
  118. NULL,
  119. };
  120. static const struct attribute_group max1111_attr_group = {
  121. .attrs = max1111_attributes,
  122. };
  123. static struct attribute *max1110_attributes[] = {
  124. &sensor_dev_attr_in4_input.dev_attr.attr,
  125. &sensor_dev_attr_in5_input.dev_attr.attr,
  126. &sensor_dev_attr_in6_input.dev_attr.attr,
  127. &sensor_dev_attr_in7_input.dev_attr.attr,
  128. NULL,
  129. };
  130. static const struct attribute_group max1110_attr_group = {
  131. .attrs = max1110_attributes,
  132. };
  133. static int setup_transfer(struct max1111_data *data)
  134. {
  135. struct spi_message *m;
  136. struct spi_transfer *x;
  137. m = &data->msg;
  138. x = &data->xfer[0];
  139. spi_message_init(m);
  140. x->tx_buf = &data->tx_buf[0];
  141. x->len = MAX1111_TX_BUF_SIZE;
  142. spi_message_add_tail(x, m);
  143. x++;
  144. x->rx_buf = &data->rx_buf[0];
  145. x->len = MAX1111_RX_BUF_SIZE;
  146. spi_message_add_tail(x, m);
  147. return 0;
  148. }
  149. static int max1111_probe(struct spi_device *spi)
  150. {
  151. enum chips chip = spi_get_device_id(spi)->driver_data;
  152. struct max1111_data *data;
  153. int err;
  154. spi->bits_per_word = 8;
  155. spi->mode = SPI_MODE_0;
  156. err = spi_setup(spi);
  157. if (err < 0)
  158. return err;
  159. data = devm_kzalloc(&spi->dev, sizeof(struct max1111_data), GFP_KERNEL);
  160. if (data == NULL)
  161. return -ENOMEM;
  162. switch (chip) {
  163. case max1110:
  164. data->lsb = 8;
  165. data->sel_sh = MAX1110_CTRL_SEL_SH;
  166. break;
  167. case max1111:
  168. data->lsb = 8;
  169. data->sel_sh = MAX1111_CTRL_SEL_SH;
  170. break;
  171. case max1112:
  172. data->lsb = 16;
  173. data->sel_sh = MAX1110_CTRL_SEL_SH;
  174. break;
  175. case max1113:
  176. data->lsb = 16;
  177. data->sel_sh = MAX1111_CTRL_SEL_SH;
  178. break;
  179. }
  180. err = setup_transfer(data);
  181. if (err)
  182. return err;
  183. mutex_init(&data->drvdata_lock);
  184. data->spi = spi;
  185. spi_set_drvdata(spi, data);
  186. err = sysfs_create_group(&spi->dev.kobj, &max1111_attr_group);
  187. if (err) {
  188. dev_err(&spi->dev, "failed to create attribute group\n");
  189. return err;
  190. }
  191. if (chip == max1110 || chip == max1112) {
  192. err = sysfs_create_group(&spi->dev.kobj, &max1110_attr_group);
  193. if (err) {
  194. dev_err(&spi->dev,
  195. "failed to create extended attribute group\n");
  196. goto err_remove;
  197. }
  198. }
  199. data->hwmon_dev = hwmon_device_register(&spi->dev);
  200. if (IS_ERR(data->hwmon_dev)) {
  201. dev_err(&spi->dev, "failed to create hwmon device\n");
  202. err = PTR_ERR(data->hwmon_dev);
  203. goto err_remove;
  204. }
  205. #ifdef CONFIG_SHARPSL_PM
  206. the_max1111 = data;
  207. #endif
  208. return 0;
  209. err_remove:
  210. sysfs_remove_group(&spi->dev.kobj, &max1110_attr_group);
  211. sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group);
  212. return err;
  213. }
  214. static void max1111_remove(struct spi_device *spi)
  215. {
  216. struct max1111_data *data = spi_get_drvdata(spi);
  217. #ifdef CONFIG_SHARPSL_PM
  218. the_max1111 = NULL;
  219. #endif
  220. hwmon_device_unregister(data->hwmon_dev);
  221. sysfs_remove_group(&spi->dev.kobj, &max1110_attr_group);
  222. sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group);
  223. mutex_destroy(&data->drvdata_lock);
  224. }
  225. static const struct spi_device_id max1111_ids[] = {
  226. { "max1110", max1110 },
  227. { "max1111", max1111 },
  228. { "max1112", max1112 },
  229. { "max1113", max1113 },
  230. { },
  231. };
  232. MODULE_DEVICE_TABLE(spi, max1111_ids);
  233. static struct spi_driver max1111_driver = {
  234. .driver = {
  235. .name = "max1111",
  236. },
  237. .id_table = max1111_ids,
  238. .probe = max1111_probe,
  239. .remove = max1111_remove,
  240. };
  241. module_spi_driver(max1111_driver);
  242. MODULE_AUTHOR("Eric Miao <[email protected]>");
  243. MODULE_DESCRIPTION("MAX1110/MAX1111/MAX1112/MAX1113 ADC Driver");
  244. MODULE_LICENSE("GPL");