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 return max1111_read(&the_max1111->spi->dev, channel); 89 } 90 EXPORT_SYMBOL(max1111_read_channel); 91 #endif 92 93 /* 94 * NOTE: SPI devices do not have a default 'name' attribute, which is 95 * likely to be used by hwmon applications to distinguish between 96 * different devices, explicitly add a name attribute here. 97 */ 98 static ssize_t show_name(struct device *dev, 99 struct device_attribute *attr, char *buf) 100 { 101 return sprintf(buf, "%s\n", to_spi_device(dev)->modalias); 102 } 103 104 static ssize_t show_adc(struct device *dev, 105 struct device_attribute *attr, char *buf) 106 { 107 struct max1111_data *data = dev_get_drvdata(dev); 108 int channel = to_sensor_dev_attr(attr)->index; 109 int ret; 110 111 ret = max1111_read(dev, channel); 112 if (ret < 0) 113 return ret; 114 115 /* 116 * Assume the reference voltage to be 2.048V or 4.096V, with an 8-bit 117 * sample. The LSB weight is 8mV or 16mV depending on the chip type. 118 */ 119 return sprintf(buf, "%d\n", ret * data->lsb); 120 } 121 122 #define MAX1111_ADC_ATTR(_id) \ 123 SENSOR_DEVICE_ATTR(in##_id##_input, S_IRUGO, show_adc, NULL, _id) 124 125 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL); 126 static MAX1111_ADC_ATTR(0); 127 static MAX1111_ADC_ATTR(1); 128 static MAX1111_ADC_ATTR(2); 129 static MAX1111_ADC_ATTR(3); 130 static MAX1111_ADC_ATTR(4); 131 static MAX1111_ADC_ATTR(5); 132 static MAX1111_ADC_ATTR(6); 133 static MAX1111_ADC_ATTR(7); 134 135 static struct attribute *max1111_attributes[] = { 136 &dev_attr_name.attr, 137 &sensor_dev_attr_in0_input.dev_attr.attr, 138 &sensor_dev_attr_in1_input.dev_attr.attr, 139 &sensor_dev_attr_in2_input.dev_attr.attr, 140 &sensor_dev_attr_in3_input.dev_attr.attr, 141 NULL, 142 }; 143 144 static const struct attribute_group max1111_attr_group = { 145 .attrs = max1111_attributes, 146 }; 147 148 static struct attribute *max1110_attributes[] = { 149 &sensor_dev_attr_in4_input.dev_attr.attr, 150 &sensor_dev_attr_in5_input.dev_attr.attr, 151 &sensor_dev_attr_in6_input.dev_attr.attr, 152 &sensor_dev_attr_in7_input.dev_attr.attr, 153 NULL, 154 }; 155 156 static const struct attribute_group max1110_attr_group = { 157 .attrs = max1110_attributes, 158 }; 159 160 static int setup_transfer(struct max1111_data *data) 161 { 162 struct spi_message *m; 163 struct spi_transfer *x; 164 165 m = &data->msg; 166 x = &data->xfer[0]; 167 168 spi_message_init(m); 169 170 x->tx_buf = &data->tx_buf[0]; 171 x->len = MAX1111_TX_BUF_SIZE; 172 spi_message_add_tail(x, m); 173 174 x++; 175 x->rx_buf = &data->rx_buf[0]; 176 x->len = MAX1111_RX_BUF_SIZE; 177 spi_message_add_tail(x, m); 178 179 return 0; 180 } 181 182 static int max1111_probe(struct spi_device *spi) 183 { 184 enum chips chip = spi_get_device_id(spi)->driver_data; 185 struct max1111_data *data; 186 int err; 187 188 spi->bits_per_word = 8; 189 spi->mode = SPI_MODE_0; 190 err = spi_setup(spi); 191 if (err < 0) 192 return err; 193 194 data = devm_kzalloc(&spi->dev, sizeof(struct max1111_data), GFP_KERNEL); 195 if (data == NULL) 196 return -ENOMEM; 197 198 switch (chip) { 199 case max1110: 200 data->lsb = 8; 201 data->sel_sh = MAX1110_CTRL_SEL_SH; 202 break; 203 case max1111: 204 data->lsb = 8; 205 data->sel_sh = MAX1111_CTRL_SEL_SH; 206 break; 207 case max1112: 208 data->lsb = 16; 209 data->sel_sh = MAX1110_CTRL_SEL_SH; 210 break; 211 case max1113: 212 data->lsb = 16; 213 data->sel_sh = MAX1111_CTRL_SEL_SH; 214 break; 215 } 216 err = setup_transfer(data); 217 if (err) 218 return err; 219 220 mutex_init(&data->drvdata_lock); 221 222 data->spi = spi; 223 spi_set_drvdata(spi, data); 224 225 err = sysfs_create_group(&spi->dev.kobj, &max1111_attr_group); 226 if (err) { 227 dev_err(&spi->dev, "failed to create attribute group\n"); 228 return err; 229 } 230 if (chip == max1110 || chip == max1112) { 231 err = sysfs_create_group(&spi->dev.kobj, &max1110_attr_group); 232 if (err) { 233 dev_err(&spi->dev, 234 "failed to create extended attribute group\n"); 235 goto err_remove; 236 } 237 } 238 239 data->hwmon_dev = hwmon_device_register(&spi->dev); 240 if (IS_ERR(data->hwmon_dev)) { 241 dev_err(&spi->dev, "failed to create hwmon device\n"); 242 err = PTR_ERR(data->hwmon_dev); 243 goto err_remove; 244 } 245 246 #ifdef CONFIG_SHARPSL_PM 247 the_max1111 = data; 248 #endif 249 return 0; 250 251 err_remove: 252 sysfs_remove_group(&spi->dev.kobj, &max1110_attr_group); 253 sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group); 254 return err; 255 } 256 257 static int max1111_remove(struct spi_device *spi) 258 { 259 struct max1111_data *data = spi_get_drvdata(spi); 260 261 hwmon_device_unregister(data->hwmon_dev); 262 sysfs_remove_group(&spi->dev.kobj, &max1110_attr_group); 263 sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group); 264 mutex_destroy(&data->drvdata_lock); 265 return 0; 266 } 267 268 static const struct spi_device_id max1111_ids[] = { 269 { "max1110", max1110 }, 270 { "max1111", max1111 }, 271 { "max1112", max1112 }, 272 { "max1113", max1113 }, 273 { }, 274 }; 275 MODULE_DEVICE_TABLE(spi, max1111_ids); 276 277 static struct spi_driver max1111_driver = { 278 .driver = { 279 .name = "max1111", 280 .owner = THIS_MODULE, 281 }, 282 .id_table = max1111_ids, 283 .probe = max1111_probe, 284 .remove = max1111_remove, 285 }; 286 287 module_spi_driver(max1111_driver); 288 289 MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>"); 290 MODULE_DESCRIPTION("MAX1110/MAX1111/MAX1112/MAX1113 ADC Driver"); 291 MODULE_LICENSE("GPL"); 292