/* * 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> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * publishhed by the Free Software Foundation. */ #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> #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 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; uint8_t *rx_buf; }; static int max1111_read(struct device *dev, int channel) { struct max1111_data *data = dev_get_drvdata(dev); uint8_t v1, v2; int err; data->tx_buf[0] = (channel << MAX1111_CTRL_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); return err; } v1 = data->rx_buf[0]; v2 = data->rx_buf[1]; 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) { 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 show_name(struct device *dev, struct device_attribute *attr, char *buf) { return sprintf(buf, "max1111\n"); } static ssize_t show_adc(struct device *dev, struct device_attribute *attr, char *buf) { int channel = to_sensor_dev_attr(attr)->index; int ret; ret = max1111_read(dev, channel); if (ret < 0) return ret; return sprintf(buf, "%d\n", ret); } #define MAX1111_ADC_ATTR(_id) \ SENSOR_DEVICE_ATTR(adc##_id##_in, S_IRUGO, show_adc, NULL, _id) static DEVICE_ATTR(name, S_IRUGO, show_name, NULL); static MAX1111_ADC_ATTR(0); static MAX1111_ADC_ATTR(1); static MAX1111_ADC_ATTR(2); static MAX1111_ADC_ATTR(3); static struct attribute *max1111_attributes[] = { &dev_attr_name.attr, &sensor_dev_attr_adc0_in.dev_attr.attr, &sensor_dev_attr_adc1_in.dev_attr.attr, &sensor_dev_attr_adc2_in.dev_attr.attr, &sensor_dev_attr_adc3_in.dev_attr.attr, NULL, }; static const struct attribute_group max1111_attr_group = { .attrs = max1111_attributes, }; static int setup_transfer(struct max1111_data *data) { struct spi_message *m; struct spi_transfer *x; data->tx_buf = kmalloc(MAX1111_TX_BUF_SIZE, GFP_KERNEL); if (!data->tx_buf) return -ENOMEM; data->rx_buf = kmalloc(MAX1111_RX_BUF_SIZE, GFP_KERNEL); if (!data->rx_buf) { kfree(data->tx_buf); return -ENOMEM; } m = &data->msg; x = &data->xfer[0]; spi_message_init(m); x->tx_buf = &data->tx_buf[0]; x->len = 1; spi_message_add_tail(x, m); x++; x->rx_buf = &data->rx_buf[0]; x->len = 2; spi_message_add_tail(x, m); return 0; } static int __devinit max1111_probe(struct spi_device *spi) { 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 = kzalloc(sizeof(struct max1111_data), GFP_KERNEL); if (data == NULL) { dev_err(&spi->dev, "failed to allocate memory\n"); return -ENOMEM; } err = setup_transfer(data); if (err) goto err_free_data; 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"); goto err_free_all; } 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, &max1111_attr_group); err_free_all: kfree(data->rx_buf); kfree(data->tx_buf); err_free_data: kfree(data); return err; } static int __devexit max1111_remove(struct spi_device *spi) { struct max1111_data *data = spi_get_drvdata(spi); hwmon_device_unregister(data->hwmon_dev); sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group); kfree(data->rx_buf); kfree(data->tx_buf); kfree(data); return 0; } static struct spi_driver max1111_driver = { .driver = { .name = "max1111", .owner = THIS_MODULE, }, .probe = max1111_probe, .remove = __devexit_p(max1111_remove), }; static int __init max1111_init(void) { return spi_register_driver(&max1111_driver); } module_init(max1111_init); static void __exit max1111_exit(void) { spi_unregister_driver(&max1111_driver); } module_exit(max1111_exit); MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>"); MODULE_DESCRIPTION("MAX1111 ADC Driver"); MODULE_LICENSE("GPL"); MODULE_ALIAS("spi:max1111");