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