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* API bus driver for ADT7316/7/8 ADT7516/7/9 digital temperature
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* Copyright 2010 Analog Devices Inc.
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* Licensed under the GPL-2 or later.
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#include <linux/device.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/interrupt.h>
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#include <linux/spi/spi.h>
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#define ADT7316_SPI_MAX_FREQ_HZ 5000000
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#define ADT7316_SPI_CMD_READ 0x91
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#define ADT7316_SPI_CMD_WRITE 0x90
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* adt7316 register access by SPI
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static int adt7316_spi_multi_read(void *client, u8 reg, u8 count, u8 *data)
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struct spi_device *spi_dev = client;
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if (count > ADT7316_REG_MAX_ADDR)
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count = ADT7316_REG_MAX_ADDR;
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cmd[0] = ADT7316_SPI_CMD_WRITE;
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ret = spi_write(spi_dev, cmd, 2);
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dev_err(&spi_dev->dev, "SPI fail to select reg\n");
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cmd[0] = ADT7316_SPI_CMD_READ;
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ret = spi_write_then_read(spi_dev, cmd, 1, data, count);
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dev_err(&spi_dev->dev, "SPI read data error\n");
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static int adt7316_spi_multi_write(void *client, u8 reg, u8 count, u8 *data)
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struct spi_device *spi_dev = client;
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u8 buf[ADT7316_REG_MAX_ADDR + 2];
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if (count > ADT7316_REG_MAX_ADDR)
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count = ADT7316_REG_MAX_ADDR;
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buf[0] = ADT7316_SPI_CMD_WRITE;
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for (i = 0; i < count; i++)
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ret = spi_write(spi_dev, buf, count + 2);
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dev_err(&spi_dev->dev, "SPI write error\n");
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static int adt7316_spi_read(void *client, u8 reg, u8 *data)
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return adt7316_spi_multi_read(client, reg, 1, data);
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static int adt7316_spi_write(void *client, u8 reg, u8 val)
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return adt7316_spi_multi_write(client, reg, 1, &val);
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* device probe and remove
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static int __devinit adt7316_spi_probe(struct spi_device *spi_dev)
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struct adt7316_bus bus = {
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.irq_flags = IRQF_TRIGGER_LOW,
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.read = adt7316_spi_read,
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.write = adt7316_spi_write,
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.multi_read = adt7316_spi_multi_read,
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.multi_write = adt7316_spi_multi_write,
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/* don't exceed max specified SPI CLK frequency */
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if (spi_dev->max_speed_hz > ADT7316_SPI_MAX_FREQ_HZ) {
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dev_err(&spi_dev->dev, "SPI CLK %d Hz?\n",
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spi_dev->max_speed_hz);
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/* switch from default I2C protocol to SPI protocol */
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adt7316_spi_write(spi_dev, 0, 0);
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adt7316_spi_write(spi_dev, 0, 0);
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adt7316_spi_write(spi_dev, 0, 0);
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return adt7316_probe(&spi_dev->dev, &bus, spi_dev->modalias);
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static int __devexit adt7316_spi_remove(struct spi_device *spi_dev)
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return adt7316_remove(&spi_dev->dev);
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static const struct spi_device_id adt7316_spi_id[] = {
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MODULE_DEVICE_TABLE(spi, adt7316_spi_id);
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static int adt7316_spi_suspend(struct spi_device *spi_dev, pm_message_t message)
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return adt7316_disable(&spi_dev->dev);
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static int adt7316_spi_resume(struct spi_device *spi_dev)
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return adt7316_enable(&spi_dev->dev);
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# define adt7316_spi_suspend NULL
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# define adt7316_spi_resume NULL
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static struct spi_driver adt7316_driver = {
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.bus = &spi_bus_type,
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.owner = THIS_MODULE,
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.probe = adt7316_spi_probe,
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.remove = __devexit_p(adt7316_spi_remove),
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.suspend = adt7316_spi_suspend,
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.resume = adt7316_spi_resume,
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.id_table = adt7316_spi_id,
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static __init int adt7316_spi_init(void)
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return spi_register_driver(&adt7316_driver);
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static __exit void adt7316_spi_exit(void)
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spi_unregister_driver(&adt7316_driver);
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MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
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MODULE_DESCRIPTION("SPI bus driver for Analog Devices ADT7316/7/8 and"
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"ADT7516/7/9 digital temperature sensor, ADC and DAC");
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MODULE_LICENSE("GPL v2");
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module_init(adt7316_spi_init);
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module_exit(adt7316_spi_exit);