// SPDX-License-Identifier: GPL-2.0-only /* * max1111.c - +2.7V, Low-Power, Multichannel, Serial 8-bit ADCs * * Based on arch/arm/mach-pxa/corgi_ssp.c * * Copyright (C) 2004-2005 Richard Purdie * * Copyright (C) 2008 Marvell International Ltd. * Eric Miao <eric.miao@marvell.com> */ #include <linux/module.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/err.h> #include <linux/hwmon.h> #include <linux/hwmon-sysfs.h> #include <linux/spi/spi.h> #include <linux/slab.h> enum chips { max1110, max1111, max1112, max1113 }; #define MAX1111_TX_BUF_SIZE 1 #define MAX1111_RX_BUF_SIZE 2 /* MAX1111 Commands */ #define MAX1111_CTRL_PD0 (1u << 0) #define MAX1111_CTRL_PD1 (1u << 1) #define MAX1111_CTRL_SGL (1u << 2) #define MAX1111_CTRL_UNI (1u << 3) #define MAX1110_CTRL_SEL_SH (4) #define MAX1111_CTRL_SEL_SH (5) /* NOTE: bit 4 is ignored */ #define MAX1111_CTRL_STR (1u << 7) struct max1111_data { struct spi_device *spi; struct device *hwmon_dev; struct spi_message msg; struct spi_transfer xfer[2]; uint8_t tx_buf[MAX1111_TX_BUF_SIZE]; uint8_t rx_buf[MAX1111_RX_BUF_SIZE]; struct mutex drvdata_lock; /* protect msg, xfer and buffers from multiple access */ int sel_sh; int lsb; }; static int max1111_read(struct device *dev, int channel) { struct max1111_data *data = dev_get_drvdata(dev); uint8_t v1, v2; int err; /* writing to drvdata struct is not thread safe, wait on mutex */ mutex_lock(&data->drvdata_lock); data->tx_buf[0] = (channel << data->sel_sh) | MAX1111_CTRL_PD0 | MAX1111_CTRL_PD1 | MAX1111_CTRL_SGL | MAX1111_CTRL_UNI | MAX1111_CTRL_STR; err = spi_sync(data->spi, &data->msg); if (err < 0) { dev_err(dev, "spi_sync failed with %d\n", err); mutex_unlock(&data->drvdata_lock); return err; } v1 = data->rx_buf[0]; v2 = data->rx_buf[1]; mutex_unlock(&data->drvdata_lock); if ((v1 & 0xc0) || (v2 & 0x3f)) return -EINVAL; return (v1 << 2) | (v2 >> 6); } #ifdef CONFIG_SHARPSL_PM static struct max1111_data *the_max1111; int max1111_read_channel(int channel) { if (!the_max1111 || !the_max1111->spi) return -ENODEV; return max1111_read(&the_max1111->spi->dev, channel); } EXPORT_SYMBOL(max1111_read_channel); #endif /* * NOTE: SPI devices do not have a default 'name' attribute, which is * likely to be used by hwmon applications to distinguish between * different devices, explicitly add a name attribute here. */ static ssize_t name_show(struct device *dev, struct device_attribute *attr, char *buf) { return sprintf(buf, "%s\n", to_spi_device(dev)->modalias); } static ssize_t show_adc(struct device *dev, struct device_attribute *attr, char *buf) { struct max1111_data *data = dev_get_drvdata(dev); int channel = to_sensor_dev_attr(attr)->index; int ret; ret = max1111_read(dev, channel); if (ret < 0) return ret; /* * Assume the reference voltage to be 2.048V or 4.096V, with an 8-bit * sample. The LSB weight is 8mV or 16mV depending on the chip type. */ return sprintf(buf, "%d\n", ret * data->lsb); } #define MAX1111_ADC_ATTR(_id) \ SENSOR_DEVICE_ATTR(in##_id##_input, S_IRUGO, show_adc, NULL, _id) static DEVICE_ATTR_RO(name); static MAX1111_ADC_ATTR(0); static MAX1111_ADC_ATTR(1); static MAX1111_ADC_ATTR(2); static MAX1111_ADC_ATTR(3); static MAX1111_ADC_ATTR(4); static MAX1111_ADC_ATTR(5); static MAX1111_ADC_ATTR(6); static MAX1111_ADC_ATTR(7); static struct attribute *max1111_attributes[] = { &dev_attr_name.attr, &sensor_dev_attr_in0_input.dev_attr.attr, &sensor_dev_attr_in1_input.dev_attr.attr, &sensor_dev_attr_in2_input.dev_attr.attr, &sensor_dev_attr_in3_input.dev_attr.attr, NULL, }; static const struct attribute_group max1111_attr_group = { .attrs = max1111_attributes, }; static struct attribute *max1110_attributes[] = { &sensor_dev_attr_in4_input.dev_attr.attr, &sensor_dev_attr_in5_input.dev_attr.attr, &sensor_dev_attr_in6_input.dev_attr.attr, &sensor_dev_attr_in7_input.dev_attr.attr, NULL, }; static const struct attribute_group max1110_attr_group = { .attrs = max1110_attributes, }; static int setup_transfer(struct max1111_data *data) { struct spi_message *m; struct spi_transfer *x; m = &data->msg; x = &data->xfer[0]; spi_message_init(m); x->tx_buf = &data->tx_buf[0]; x->len = MAX1111_TX_BUF_SIZE; spi_message_add_tail(x, m); x++; x->rx_buf = &data->rx_buf[0]; x->len = MAX1111_RX_BUF_SIZE; spi_message_add_tail(x, m); return 0; } static int max1111_probe(struct spi_device *spi) { enum chips chip = spi_get_device_id(spi)->driver_data; struct max1111_data *data; int err; spi->bits_per_word = 8; spi->mode = SPI_MODE_0; err = spi_setup(spi); if (err < 0) return err; data = devm_kzalloc(&spi->dev, sizeof(struct max1111_data), GFP_KERNEL); if (data == NULL) return -ENOMEM; switch (chip) { case max1110: data->lsb = 8; data->sel_sh = MAX1110_CTRL_SEL_SH; break; case max1111: data->lsb = 8; data->sel_sh = MAX1111_CTRL_SEL_SH; break; case max1112: data->lsb = 16; data->sel_sh = MAX1110_CTRL_SEL_SH; break; case max1113: data->lsb = 16; data->sel_sh = MAX1111_CTRL_SEL_SH; break; } err = setup_transfer(data); if (err) return err; mutex_init(&data->drvdata_lock); data->spi = spi; spi_set_drvdata(spi, data); err = sysfs_create_group(&spi->dev.kobj, &max1111_attr_group); if (err) { dev_err(&spi->dev, "failed to create attribute group\n"); return err; } if (chip == max1110 || chip == max1112) { err = sysfs_create_group(&spi->dev.kobj, &max1110_attr_group); if (err) { dev_err(&spi->dev, "failed to create extended attribute group\n"); goto err_remove; } } data->hwmon_dev = hwmon_device_register(&spi->dev); if (IS_ERR(data->hwmon_dev)) { dev_err(&spi->dev, "failed to create hwmon device\n"); err = PTR_ERR(data->hwmon_dev); goto err_remove; } #ifdef CONFIG_SHARPSL_PM the_max1111 = data; #endif return 0; err_remove: sysfs_remove_group(&spi->dev.kobj, &max1110_attr_group); sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group); return err; } static int max1111_remove(struct spi_device *spi) { struct max1111_data *data = spi_get_drvdata(spi); #ifdef CONFIG_SHARPSL_PM the_max1111 = NULL; #endif hwmon_device_unregister(data->hwmon_dev); sysfs_remove_group(&spi->dev.kobj, &max1110_attr_group); sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group); mutex_destroy(&data->drvdata_lock); return 0; } static const struct spi_device_id max1111_ids[] = { { "max1110", max1110 }, { "max1111", max1111 }, { "max1112", max1112 }, { "max1113", max1113 }, { }, }; MODULE_DEVICE_TABLE(spi, max1111_ids); static struct spi_driver max1111_driver = { .driver = { .name = "max1111", }, .id_table = max1111_ids, .probe = max1111_probe, .remove = max1111_remove, }; module_spi_driver(max1111_driver); MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>"); MODULE_DESCRIPTION("MAX1110/MAX1111/MAX1112/MAX1113 ADC Driver"); MODULE_LICENSE("GPL");