1 /* 2 * max1111.c - +2.7V, Low-Power, Multichannel, Serial 8-bit ADCs 3 * 4 * Based on arch/arm/mach-pxa/corgi_ssp.c 5 * 6 * Copyright (C) 2004-2005 Richard Purdie 7 * 8 * Copyright (C) 2008 Marvell International Ltd. 9 * Eric Miao <eric.miao@marvell.com> 10 * 11 * This program is free software; you can redistribute it and/or modify 12 * it under the terms of the GNU General Public License version 2 as 13 * publishhed by the Free Software Foundation. 14 */ 15 16 #include <linux/module.h> 17 #include <linux/kernel.h> 18 #include <linux/init.h> 19 #include <linux/err.h> 20 #include <linux/hwmon.h> 21 #include <linux/hwmon-sysfs.h> 22 #include <linux/spi/spi.h> 23 #include <linux/slab.h> 24 25 enum chips { max1110, max1111, max1112, max1113 }; 26 27 #define MAX1111_TX_BUF_SIZE 1 28 #define MAX1111_RX_BUF_SIZE 2 29 30 /* MAX1111 Commands */ 31 #define MAX1111_CTRL_PD0 (1u << 0) 32 #define MAX1111_CTRL_PD1 (1u << 1) 33 #define MAX1111_CTRL_SGL (1u << 2) 34 #define MAX1111_CTRL_UNI (1u << 3) 35 #define MAX1110_CTRL_SEL_SH (4) 36 #define MAX1111_CTRL_SEL_SH (5) /* NOTE: bit 4 is ignored */ 37 #define MAX1111_CTRL_STR (1u << 7) 38 39 struct max1111_data { 40 struct spi_device *spi; 41 struct device *hwmon_dev; 42 struct spi_message msg; 43 struct spi_transfer xfer[2]; 44 uint8_t tx_buf[MAX1111_TX_BUF_SIZE]; 45 uint8_t rx_buf[MAX1111_RX_BUF_SIZE]; 46 struct mutex drvdata_lock; 47 /* protect msg, xfer and buffers from multiple access */ 48 int sel_sh; 49 int lsb; 50 }; 51 52 static int max1111_read(struct device *dev, int channel) 53 { 54 struct max1111_data *data = dev_get_drvdata(dev); 55 uint8_t v1, v2; 56 int err; 57 58 /* writing to drvdata struct is not thread safe, wait on mutex */ 59 mutex_lock(&data->drvdata_lock); 60 61 data->tx_buf[0] = (channel << data->sel_sh) | 62 MAX1111_CTRL_PD0 | MAX1111_CTRL_PD1 | 63 MAX1111_CTRL_SGL | MAX1111_CTRL_UNI | MAX1111_CTRL_STR; 64 65 err = spi_sync(data->spi, &data->msg); 66 if (err < 0) { 67 dev_err(dev, "spi_sync failed with %d\n", err); 68 mutex_unlock(&data->drvdata_lock); 69 return err; 70 } 71 72 v1 = data->rx_buf[0]; 73 v2 = data->rx_buf[1]; 74 75 mutex_unlock(&data->drvdata_lock); 76 77 if ((v1 & 0xc0) || (v2 & 0x3f)) 78 return -EINVAL; 79 80 return (v1 << 2) | (v2 >> 6); 81 } 82 83 #ifdef CONFIG_SHARPSL_PM 84 static struct max1111_data *the_max1111; 85 86 int max1111_read_channel(int channel) 87 { 88 if (!the_max1111 || !the_max1111->spi) 89 return -ENODEV; 90 91 return max1111_read(&the_max1111->spi->dev, channel); 92 } 93 EXPORT_SYMBOL(max1111_read_channel); 94 #endif 95 96 /* 97 * NOTE: SPI devices do not have a default 'name' attribute, which is 98 * likely to be used by hwmon applications to distinguish between 99 * different devices, explicitly add a name attribute here. 100 */ 101 static ssize_t show_name(struct device *dev, 102 struct device_attribute *attr, char *buf) 103 { 104 return sprintf(buf, "%s\n", to_spi_device(dev)->modalias); 105 } 106 107 static ssize_t show_adc(struct device *dev, 108 struct device_attribute *attr, char *buf) 109 { 110 struct max1111_data *data = dev_get_drvdata(dev); 111 int channel = to_sensor_dev_attr(attr)->index; 112 int ret; 113 114 ret = max1111_read(dev, channel); 115 if (ret < 0) 116 return ret; 117 118 /* 119 * Assume the reference voltage to be 2.048V or 4.096V, with an 8-bit 120 * sample. The LSB weight is 8mV or 16mV depending on the chip type. 121 */ 122 return sprintf(buf, "%d\n", ret * data->lsb); 123 } 124 125 #define MAX1111_ADC_ATTR(_id) \ 126 SENSOR_DEVICE_ATTR(in##_id##_input, S_IRUGO, show_adc, NULL, _id) 127 128 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL); 129 static MAX1111_ADC_ATTR(0); 130 static MAX1111_ADC_ATTR(1); 131 static MAX1111_ADC_ATTR(2); 132 static MAX1111_ADC_ATTR(3); 133 static MAX1111_ADC_ATTR(4); 134 static MAX1111_ADC_ATTR(5); 135 static MAX1111_ADC_ATTR(6); 136 static MAX1111_ADC_ATTR(7); 137 138 static struct attribute *max1111_attributes[] = { 139 &dev_attr_name.attr, 140 &sensor_dev_attr_in0_input.dev_attr.attr, 141 &sensor_dev_attr_in1_input.dev_attr.attr, 142 &sensor_dev_attr_in2_input.dev_attr.attr, 143 &sensor_dev_attr_in3_input.dev_attr.attr, 144 NULL, 145 }; 146 147 static const struct attribute_group max1111_attr_group = { 148 .attrs = max1111_attributes, 149 }; 150 151 static struct attribute *max1110_attributes[] = { 152 &sensor_dev_attr_in4_input.dev_attr.attr, 153 &sensor_dev_attr_in5_input.dev_attr.attr, 154 &sensor_dev_attr_in6_input.dev_attr.attr, 155 &sensor_dev_attr_in7_input.dev_attr.attr, 156 NULL, 157 }; 158 159 static const struct attribute_group max1110_attr_group = { 160 .attrs = max1110_attributes, 161 }; 162 163 static int setup_transfer(struct max1111_data *data) 164 { 165 struct spi_message *m; 166 struct spi_transfer *x; 167 168 m = &data->msg; 169 x = &data->xfer[0]; 170 171 spi_message_init(m); 172 173 x->tx_buf = &data->tx_buf[0]; 174 x->len = MAX1111_TX_BUF_SIZE; 175 spi_message_add_tail(x, m); 176 177 x++; 178 x->rx_buf = &data->rx_buf[0]; 179 x->len = MAX1111_RX_BUF_SIZE; 180 spi_message_add_tail(x, m); 181 182 return 0; 183 } 184 185 static int max1111_probe(struct spi_device *spi) 186 { 187 enum chips chip = spi_get_device_id(spi)->driver_data; 188 struct max1111_data *data; 189 int err; 190 191 spi->bits_per_word = 8; 192 spi->mode = SPI_MODE_0; 193 err = spi_setup(spi); 194 if (err < 0) 195 return err; 196 197 data = devm_kzalloc(&spi->dev, sizeof(struct max1111_data), GFP_KERNEL); 198 if (data == NULL) 199 return -ENOMEM; 200 201 switch (chip) { 202 case max1110: 203 data->lsb = 8; 204 data->sel_sh = MAX1110_CTRL_SEL_SH; 205 break; 206 case max1111: 207 data->lsb = 8; 208 data->sel_sh = MAX1111_CTRL_SEL_SH; 209 break; 210 case max1112: 211 data->lsb = 16; 212 data->sel_sh = MAX1110_CTRL_SEL_SH; 213 break; 214 case max1113: 215 data->lsb = 16; 216 data->sel_sh = MAX1111_CTRL_SEL_SH; 217 break; 218 } 219 err = setup_transfer(data); 220 if (err) 221 return err; 222 223 mutex_init(&data->drvdata_lock); 224 225 data->spi = spi; 226 spi_set_drvdata(spi, data); 227 228 err = sysfs_create_group(&spi->dev.kobj, &max1111_attr_group); 229 if (err) { 230 dev_err(&spi->dev, "failed to create attribute group\n"); 231 return err; 232 } 233 if (chip == max1110 || chip == max1112) { 234 err = sysfs_create_group(&spi->dev.kobj, &max1110_attr_group); 235 if (err) { 236 dev_err(&spi->dev, 237 "failed to create extended attribute group\n"); 238 goto err_remove; 239 } 240 } 241 242 data->hwmon_dev = hwmon_device_register(&spi->dev); 243 if (IS_ERR(data->hwmon_dev)) { 244 dev_err(&spi->dev, "failed to create hwmon device\n"); 245 err = PTR_ERR(data->hwmon_dev); 246 goto err_remove; 247 } 248 249 #ifdef CONFIG_SHARPSL_PM 250 the_max1111 = data; 251 #endif 252 return 0; 253 254 err_remove: 255 sysfs_remove_group(&spi->dev.kobj, &max1110_attr_group); 256 sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group); 257 return err; 258 } 259 260 static int max1111_remove(struct spi_device *spi) 261 { 262 struct max1111_data *data = spi_get_drvdata(spi); 263 264 #ifdef CONFIG_SHARPSL_PM 265 the_max1111 = NULL; 266 #endif 267 hwmon_device_unregister(data->hwmon_dev); 268 sysfs_remove_group(&spi->dev.kobj, &max1110_attr_group); 269 sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group); 270 mutex_destroy(&data->drvdata_lock); 271 return 0; 272 } 273 274 static const struct spi_device_id max1111_ids[] = { 275 { "max1110", max1110 }, 276 { "max1111", max1111 }, 277 { "max1112", max1112 }, 278 { "max1113", max1113 }, 279 { }, 280 }; 281 MODULE_DEVICE_TABLE(spi, max1111_ids); 282 283 static struct spi_driver max1111_driver = { 284 .driver = { 285 .name = "max1111", 286 }, 287 .id_table = max1111_ids, 288 .probe = max1111_probe, 289 .remove = max1111_remove, 290 }; 291 292 module_spi_driver(max1111_driver); 293 294 MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>"); 295 MODULE_DESCRIPTION("MAX1110/MAX1111/MAX1112/MAX1113 ADC Driver"); 296 MODULE_LICENSE("GPL"); 297