--- /dev/null
+/*
+ * 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>
+
+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)
+{
+ 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, "%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(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 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);
+
+ 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",
+ .owner = THIS_MODULE,
+ },
+ .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");
Code Review / kvmfornfv.git / blobdiff