294 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * max1111.c - +2.7V, Low-Power, Multichannel, Serial 8-bit ADCs4 *5 * Based on arch/arm/mach-pxa/corgi_ssp.c6 *7 * Copyright (C) 2004-2005 Richard Purdie8 *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 22enum chips { max1110, max1111, max1112, max1113 };23 24#define MAX1111_TX_BUF_SIZE 125#define MAX1111_RX_BUF_SIZE 226 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 36struct 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 49static 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_PM81static struct max1111_data *the_max1111;82 83int max1111_read_channel(int channel);84int 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}91EXPORT_SYMBOL(max1111_read_channel);92#endif93 94/*95 * NOTE: SPI devices do not have a default 'name' attribute, which is96 * likely to be used by hwmon applications to distinguish between97 * different devices, explicitly add a name attribute here.98 */99static 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 105static 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-bit118 * 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 126static DEVICE_ATTR_RO(name);127static MAX1111_ADC_ATTR(0);128static MAX1111_ADC_ATTR(1);129static MAX1111_ADC_ATTR(2);130static MAX1111_ADC_ATTR(3);131static MAX1111_ADC_ATTR(4);132static MAX1111_ADC_ATTR(5);133static MAX1111_ADC_ATTR(6);134static MAX1111_ADC_ATTR(7);135 136static 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 145static const struct attribute_group max1111_attr_group = {146 .attrs = max1111_attributes,147};148 149static 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 157static const struct attribute_group max1110_attr_group = {158 .attrs = max1110_attributes,159};160 161static 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 183static 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_PM248 the_max1111 = data;249#endif250 return 0;251 252err_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 258static void max1111_remove(struct spi_device *spi)259{260 struct max1111_data *data = spi_get_drvdata(spi);261 262#ifdef CONFIG_SHARPSL_PM263 the_max1111 = NULL;264#endif265 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 271static const struct spi_device_id max1111_ids[] = {272 { "max1110", max1110 },273 { "max1111", max1111 },274 { "max1112", max1112 },275 { "max1113", max1113 },276 { },277};278MODULE_DEVICE_TABLE(spi, max1111_ids);279 280static 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 289module_spi_driver(max1111_driver);290 291MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");292MODULE_DESCRIPTION("MAX1110/MAX1111/MAX1112/MAX1113 ADC Driver");293MODULE_LICENSE("GPL");294