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 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 MAX1111_CTRL_SEL_SH (5) /* NOTE: bit 4 is ignored */ 33 #define MAX1111_CTRL_STR (1u << 7) 34 35 struct max1111_data { 36 struct spi_device *spi; 37 struct device *hwmon_dev; 38 struct spi_message msg; 39 struct spi_transfer xfer[2]; 40 uint8_t *tx_buf; 41 uint8_t *rx_buf; 42 }; 43 44 static int max1111_read(struct device *dev, int channel) 45 { 46 struct max1111_data *data = dev_get_drvdata(dev); 47 uint8_t v1, v2; 48 int err; 49 50 data->tx_buf[0] = (channel << MAX1111_CTRL_SEL_SH) | 51 MAX1111_CTRL_PD0 | MAX1111_CTRL_PD1 | 52 MAX1111_CTRL_SGL | MAX1111_CTRL_UNI | MAX1111_CTRL_STR; 53 54 err = spi_sync(data->spi, &data->msg); 55 if (err < 0) { 56 dev_err(dev, "spi_sync failed with %d\n", err); 57 return err; 58 } 59 60 v1 = data->rx_buf[0]; 61 v2 = data->rx_buf[1]; 62 63 if ((v1 & 0xc0) || (v2 & 0x3f)) 64 return -EINVAL; 65 66 return (v1 << 2) | (v2 >> 6); 67 } 68 69 #ifdef CONFIG_SHARPSL_PM 70 static struct max1111_data *the_max1111; 71 72 int max1111_read_channel(int channel) 73 { 74 return max1111_read(&the_max1111->spi->dev, channel); 75 } 76 EXPORT_SYMBOL(max1111_read_channel); 77 #endif 78 79 /* 80 * NOTE: SPI devices do not have a default 'name' attribute, which is 81 * likely to be used by hwmon applications to distinguish between 82 * different devices, explicitly add a name attribute here. 83 */ 84 static ssize_t show_name(struct device *dev, 85 struct device_attribute *attr, char *buf) 86 { 87 return sprintf(buf, "max1111\n"); 88 } 89 90 static ssize_t show_adc(struct device *dev, 91 struct device_attribute *attr, char *buf) 92 { 93 int channel = to_sensor_dev_attr(attr)->index; 94 int ret; 95 96 ret = max1111_read(dev, channel); 97 if (ret < 0) 98 return ret; 99 100 return sprintf(buf, "%d\n", ret); 101 } 102 103 #define MAX1111_ADC_ATTR(_id) \ 104 SENSOR_DEVICE_ATTR(adc##_id##_in, S_IRUGO, show_adc, NULL, _id) 105 106 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL); 107 static MAX1111_ADC_ATTR(0); 108 static MAX1111_ADC_ATTR(1); 109 static MAX1111_ADC_ATTR(2); 110 static MAX1111_ADC_ATTR(3); 111 112 static struct attribute *max1111_attributes[] = { 113 &dev_attr_name.attr, 114 &sensor_dev_attr_adc0_in.dev_attr.attr, 115 &sensor_dev_attr_adc1_in.dev_attr.attr, 116 &sensor_dev_attr_adc2_in.dev_attr.attr, 117 &sensor_dev_attr_adc3_in.dev_attr.attr, 118 NULL, 119 }; 120 121 static const struct attribute_group max1111_attr_group = { 122 .attrs = max1111_attributes, 123 }; 124 125 static int setup_transfer(struct max1111_data *data) 126 { 127 struct spi_message *m; 128 struct spi_transfer *x; 129 130 data->tx_buf = kmalloc(MAX1111_TX_BUF_SIZE, GFP_KERNEL); 131 if (!data->tx_buf) 132 return -ENOMEM; 133 134 data->rx_buf = kmalloc(MAX1111_RX_BUF_SIZE, GFP_KERNEL); 135 if (!data->rx_buf) { 136 kfree(data->tx_buf); 137 return -ENOMEM; 138 } 139 140 m = &data->msg; 141 x = &data->xfer[0]; 142 143 spi_message_init(m); 144 145 x->tx_buf = &data->tx_buf[0]; 146 x->len = 1; 147 spi_message_add_tail(x, m); 148 149 x++; 150 x->rx_buf = &data->rx_buf[0]; 151 x->len = 2; 152 spi_message_add_tail(x, m); 153 154 return 0; 155 } 156 157 static int __devinit max1111_probe(struct spi_device *spi) 158 { 159 struct max1111_data *data; 160 int err; 161 162 spi->bits_per_word = 8; 163 spi->mode = SPI_MODE_0; 164 err = spi_setup(spi); 165 if (err < 0) 166 return err; 167 168 data = kzalloc(sizeof(struct max1111_data), GFP_KERNEL); 169 if (data == NULL) { 170 dev_err(&spi->dev, "failed to allocate memory\n"); 171 return -ENOMEM; 172 } 173 174 err = setup_transfer(data); 175 if (err) 176 goto err_free_data; 177 178 data->spi = spi; 179 spi_set_drvdata(spi, data); 180 181 err = sysfs_create_group(&spi->dev.kobj, &max1111_attr_group); 182 if (err) { 183 dev_err(&spi->dev, "failed to create attribute group\n"); 184 goto err_free_all; 185 } 186 187 data->hwmon_dev = hwmon_device_register(&spi->dev); 188 if (IS_ERR(data->hwmon_dev)) { 189 dev_err(&spi->dev, "failed to create hwmon device\n"); 190 err = PTR_ERR(data->hwmon_dev); 191 goto err_remove; 192 } 193 194 #ifdef CONFIG_SHARPSL_PM 195 the_max1111 = data; 196 #endif 197 return 0; 198 199 err_remove: 200 sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group); 201 err_free_all: 202 kfree(data->rx_buf); 203 kfree(data->tx_buf); 204 err_free_data: 205 kfree(data); 206 return err; 207 } 208 209 static int __devexit max1111_remove(struct spi_device *spi) 210 { 211 struct max1111_data *data = spi_get_drvdata(spi); 212 213 hwmon_device_unregister(data->hwmon_dev); 214 sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group); 215 kfree(data->rx_buf); 216 kfree(data->tx_buf); 217 kfree(data); 218 return 0; 219 } 220 221 static struct spi_driver max1111_driver = { 222 .driver = { 223 .name = "max1111", 224 .owner = THIS_MODULE, 225 }, 226 .probe = max1111_probe, 227 .remove = __devexit_p(max1111_remove), 228 }; 229 230 static int __init max1111_init(void) 231 { 232 return spi_register_driver(&max1111_driver); 233 } 234 module_init(max1111_init); 235 236 static void __exit max1111_exit(void) 237 { 238 spi_unregister_driver(&max1111_driver); 239 } 240 module_exit(max1111_exit); 241 242 MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>"); 243 MODULE_DESCRIPTION("MAX1111 ADC Driver"); 244 MODULE_LICENSE("GPL"); 245 MODULE_ALIAS("spi:max1111"); 246