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210 lines
4.9 KiB
210 lines
4.9 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* mcp3021.c - driver for Microchip MCP3021 and MCP3221 |
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* |
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* Copyright (C) 2008-2009, 2012 Freescale Semiconductor, Inc. |
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* Author: Mingkai Hu <[email protected]> |
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* Reworked by Sven Schuchmann <[email protected]> |
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* DT support added by Clemens Gruber <[email protected]> |
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* |
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* This driver export the value of analog input voltage to sysfs, the |
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* voltage unit is mV. Through the sysfs interface, lm-sensors tool |
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* can also display the input voltage. |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/hwmon.h> |
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#include <linux/slab.h> |
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#include <linux/i2c.h> |
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#include <linux/err.h> |
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#include <linux/device.h> |
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#include <linux/of.h> |
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#include <linux/of_device.h> |
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/* Vdd / reference voltage in millivolt */ |
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#define MCP3021_VDD_REF_MAX 5500 |
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#define MCP3021_VDD_REF_MIN 2700 |
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#define MCP3021_VDD_REF_DEFAULT 3300 |
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/* output format */ |
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#define MCP3021_SAR_SHIFT 2 |
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#define MCP3021_SAR_MASK 0x3ff |
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#define MCP3021_OUTPUT_RES 10 /* 10-bit resolution */ |
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#define MCP3221_SAR_SHIFT 0 |
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#define MCP3221_SAR_MASK 0xfff |
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#define MCP3221_OUTPUT_RES 12 /* 12-bit resolution */ |
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enum chips { |
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mcp3021, |
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mcp3221 |
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}; |
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/* |
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* Client data (each client gets its own) |
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*/ |
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struct mcp3021_data { |
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struct device *hwmon_dev; |
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u32 vdd; /* supply and reference voltage in millivolt */ |
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u16 sar_shift; |
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u16 sar_mask; |
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u8 output_res; |
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}; |
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static int mcp3021_read16(struct i2c_client *client) |
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{ |
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struct mcp3021_data *data = i2c_get_clientdata(client); |
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int ret; |
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u16 reg; |
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__be16 buf; |
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ret = i2c_master_recv(client, (char *)&buf, 2); |
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if (ret < 0) |
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return ret; |
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if (ret != 2) |
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return -EIO; |
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/* The output code of the MCP3021 is transmitted with MSB first. */ |
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reg = be16_to_cpu(buf); |
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/* |
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* The ten-bit output code is composed of the lower 4-bit of the |
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* first byte and the upper 6-bit of the second byte. |
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*/ |
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reg = (reg >> data->sar_shift) & data->sar_mask; |
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return reg; |
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} |
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static inline u16 volts_from_reg(struct mcp3021_data *data, u16 val) |
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{ |
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return DIV_ROUND_CLOSEST(data->vdd * val, 1 << data->output_res); |
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} |
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static ssize_t in0_input_show(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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struct i2c_client *client = to_i2c_client(dev); |
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struct mcp3021_data *data = i2c_get_clientdata(client); |
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int reg, in_input; |
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reg = mcp3021_read16(client); |
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if (reg < 0) |
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return reg; |
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in_input = volts_from_reg(data, reg); |
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return sprintf(buf, "%d\n", in_input); |
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} |
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static DEVICE_ATTR_RO(in0_input); |
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static const struct i2c_device_id mcp3021_id[]; |
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static int mcp3021_probe(struct i2c_client *client) |
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{ |
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int err; |
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struct mcp3021_data *data = NULL; |
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struct device_node *np = client->dev.of_node; |
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) |
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return -ENODEV; |
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data = devm_kzalloc(&client->dev, sizeof(struct mcp3021_data), |
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GFP_KERNEL); |
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if (!data) |
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return -ENOMEM; |
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i2c_set_clientdata(client, data); |
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if (np) { |
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if (!of_property_read_u32(np, "reference-voltage-microvolt", |
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&data->vdd)) |
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data->vdd /= 1000; |
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else |
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data->vdd = MCP3021_VDD_REF_DEFAULT; |
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} else { |
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u32 *pdata = dev_get_platdata(&client->dev); |
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if (pdata) |
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data->vdd = *pdata; |
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else |
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data->vdd = MCP3021_VDD_REF_DEFAULT; |
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} |
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switch (i2c_match_id(mcp3021_id, client)->driver_data) { |
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case mcp3021: |
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data->sar_shift = MCP3021_SAR_SHIFT; |
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data->sar_mask = MCP3021_SAR_MASK; |
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data->output_res = MCP3021_OUTPUT_RES; |
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break; |
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case mcp3221: |
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data->sar_shift = MCP3221_SAR_SHIFT; |
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data->sar_mask = MCP3221_SAR_MASK; |
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data->output_res = MCP3221_OUTPUT_RES; |
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break; |
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} |
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if (data->vdd > MCP3021_VDD_REF_MAX || data->vdd < MCP3021_VDD_REF_MIN) |
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return -EINVAL; |
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err = sysfs_create_file(&client->dev.kobj, &dev_attr_in0_input.attr); |
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if (err) |
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return err; |
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data->hwmon_dev = hwmon_device_register(&client->dev); |
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if (IS_ERR(data->hwmon_dev)) { |
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err = PTR_ERR(data->hwmon_dev); |
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goto exit_remove; |
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} |
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return 0; |
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exit_remove: |
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sysfs_remove_file(&client->dev.kobj, &dev_attr_in0_input.attr); |
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return err; |
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} |
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static int mcp3021_remove(struct i2c_client *client) |
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{ |
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struct mcp3021_data *data = i2c_get_clientdata(client); |
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hwmon_device_unregister(data->hwmon_dev); |
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sysfs_remove_file(&client->dev.kobj, &dev_attr_in0_input.attr); |
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return 0; |
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} |
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static const struct i2c_device_id mcp3021_id[] = { |
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{ "mcp3021", mcp3021 }, |
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{ "mcp3221", mcp3221 }, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(i2c, mcp3021_id); |
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#ifdef CONFIG_OF |
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static const struct of_device_id of_mcp3021_match[] = { |
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{ .compatible = "microchip,mcp3021", .data = (void *)mcp3021 }, |
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{ .compatible = "microchip,mcp3221", .data = (void *)mcp3221 }, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(of, of_mcp3021_match); |
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#endif |
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static struct i2c_driver mcp3021_driver = { |
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.driver = { |
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.name = "mcp3021", |
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.of_match_table = of_match_ptr(of_mcp3021_match), |
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}, |
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.probe_new = mcp3021_probe, |
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.remove = mcp3021_remove, |
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.id_table = mcp3021_id, |
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}; |
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module_i2c_driver(mcp3021_driver); |
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MODULE_AUTHOR("Mingkai Hu <[email protected]>"); |
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MODULE_DESCRIPTION("Microchip MCP3021/MCP3221 driver"); |
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MODULE_LICENSE("GPL");
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