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![Javier Martinez Canillas](/assets/img/avatar_default.png)
The I2C core always reports the MODALIAS uevent as "i2c:<client name" regardless if the driver was matched using the I2C id_table or the of_match_table. So the driver needs to export the I2C table and this be built into the module or udev won't have the necessary information to auto load the correct module when the device is added. Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com> Signed-off-by: Mark Brown <broonie@kernel.org>
253 lines
5.8 KiB
C
253 lines
5.8 KiB
C
/*
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* Analog Devices AD-FMCOMMS1-EBZ board I2C-SPI bridge driver
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*
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* Copyright 2012 Analog Devices Inc.
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* Author: Lars-Peter Clausen <lars@metafoo.de>
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*
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* Licensed under the GPL-2 or later.
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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/delay.h>
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#include <linux/i2c.h>
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#include <linux/spi/spi.h>
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#include <asm/unaligned.h>
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#define SPI_XCOMM_SETTINGS_LEN_OFFSET 10
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#define SPI_XCOMM_SETTINGS_3WIRE BIT(6)
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#define SPI_XCOMM_SETTINGS_CS_HIGH BIT(5)
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#define SPI_XCOMM_SETTINGS_SAMPLE_END BIT(4)
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#define SPI_XCOMM_SETTINGS_CPHA BIT(3)
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#define SPI_XCOMM_SETTINGS_CPOL BIT(2)
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#define SPI_XCOMM_SETTINGS_CLOCK_DIV_MASK 0x3
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#define SPI_XCOMM_SETTINGS_CLOCK_DIV_64 0x2
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#define SPI_XCOMM_SETTINGS_CLOCK_DIV_16 0x1
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#define SPI_XCOMM_SETTINGS_CLOCK_DIV_4 0x0
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#define SPI_XCOMM_CMD_UPDATE_CONFIG 0x03
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#define SPI_XCOMM_CMD_WRITE 0x04
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#define SPI_XCOMM_CLOCK 48000000
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struct spi_xcomm {
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struct i2c_client *i2c;
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uint16_t settings;
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uint16_t chipselect;
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unsigned int current_speed;
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uint8_t buf[63];
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};
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static int spi_xcomm_sync_config(struct spi_xcomm *spi_xcomm, unsigned int len)
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{
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uint16_t settings;
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uint8_t *buf = spi_xcomm->buf;
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settings = spi_xcomm->settings;
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settings |= len << SPI_XCOMM_SETTINGS_LEN_OFFSET;
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buf[0] = SPI_XCOMM_CMD_UPDATE_CONFIG;
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put_unaligned_be16(settings, &buf[1]);
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put_unaligned_be16(spi_xcomm->chipselect, &buf[3]);
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return i2c_master_send(spi_xcomm->i2c, buf, 5);
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}
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static void spi_xcomm_chipselect(struct spi_xcomm *spi_xcomm,
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struct spi_device *spi, int is_active)
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{
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unsigned long cs = spi->chip_select;
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uint16_t chipselect = spi_xcomm->chipselect;
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if (is_active)
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chipselect |= BIT(cs);
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else
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chipselect &= ~BIT(cs);
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spi_xcomm->chipselect = chipselect;
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}
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static int spi_xcomm_setup_transfer(struct spi_xcomm *spi_xcomm,
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struct spi_device *spi, struct spi_transfer *t, unsigned int *settings)
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{
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if (t->len > 62)
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return -EINVAL;
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if (t->speed_hz != spi_xcomm->current_speed) {
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unsigned int divider;
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divider = DIV_ROUND_UP(SPI_XCOMM_CLOCK, t->speed_hz);
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if (divider >= 64)
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*settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_64;
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else if (divider >= 16)
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*settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_16;
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else
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*settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_4;
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spi_xcomm->current_speed = t->speed_hz;
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}
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if (spi->mode & SPI_CPOL)
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*settings |= SPI_XCOMM_SETTINGS_CPOL;
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else
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*settings &= ~SPI_XCOMM_SETTINGS_CPOL;
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if (spi->mode & SPI_CPHA)
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*settings &= ~SPI_XCOMM_SETTINGS_CPHA;
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else
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*settings |= SPI_XCOMM_SETTINGS_CPHA;
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if (spi->mode & SPI_3WIRE)
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*settings |= SPI_XCOMM_SETTINGS_3WIRE;
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else
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*settings &= ~SPI_XCOMM_SETTINGS_3WIRE;
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return 0;
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}
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static int spi_xcomm_txrx_bufs(struct spi_xcomm *spi_xcomm,
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struct spi_device *spi, struct spi_transfer *t)
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{
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int ret;
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if (t->tx_buf) {
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spi_xcomm->buf[0] = SPI_XCOMM_CMD_WRITE;
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memcpy(spi_xcomm->buf + 1, t->tx_buf, t->len);
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ret = i2c_master_send(spi_xcomm->i2c, spi_xcomm->buf, t->len + 1);
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if (ret < 0)
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return ret;
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else if (ret != t->len + 1)
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return -EIO;
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} else if (t->rx_buf) {
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ret = i2c_master_recv(spi_xcomm->i2c, t->rx_buf, t->len);
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if (ret < 0)
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return ret;
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else if (ret != t->len)
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return -EIO;
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}
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return t->len;
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}
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static int spi_xcomm_transfer_one(struct spi_master *master,
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struct spi_message *msg)
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{
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struct spi_xcomm *spi_xcomm = spi_master_get_devdata(master);
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unsigned int settings = spi_xcomm->settings;
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struct spi_device *spi = msg->spi;
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unsigned cs_change = 0;
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struct spi_transfer *t;
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bool is_first = true;
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int status = 0;
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bool is_last;
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spi_xcomm_chipselect(spi_xcomm, spi, true);
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list_for_each_entry(t, &msg->transfers, transfer_list) {
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if (!t->tx_buf && !t->rx_buf && t->len) {
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status = -EINVAL;
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break;
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}
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status = spi_xcomm_setup_transfer(spi_xcomm, spi, t, &settings);
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if (status < 0)
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break;
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is_last = list_is_last(&t->transfer_list, &msg->transfers);
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cs_change = t->cs_change;
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if (cs_change ^ is_last)
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settings |= BIT(5);
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else
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settings &= ~BIT(5);
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if (t->rx_buf) {
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spi_xcomm->settings = settings;
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status = spi_xcomm_sync_config(spi_xcomm, t->len);
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if (status < 0)
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break;
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} else if (settings != spi_xcomm->settings || is_first) {
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spi_xcomm->settings = settings;
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status = spi_xcomm_sync_config(spi_xcomm, 0);
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if (status < 0)
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break;
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}
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if (t->len) {
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status = spi_xcomm_txrx_bufs(spi_xcomm, spi, t);
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if (status < 0)
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break;
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if (status > 0)
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msg->actual_length += status;
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}
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status = 0;
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if (t->delay_usecs)
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udelay(t->delay_usecs);
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is_first = false;
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}
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if (status != 0 || !cs_change)
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spi_xcomm_chipselect(spi_xcomm, spi, false);
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msg->status = status;
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spi_finalize_current_message(master);
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return status;
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}
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static int spi_xcomm_probe(struct i2c_client *i2c,
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const struct i2c_device_id *id)
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{
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struct spi_xcomm *spi_xcomm;
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struct spi_master *master;
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int ret;
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master = spi_alloc_master(&i2c->dev, sizeof(*spi_xcomm));
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if (!master)
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return -ENOMEM;
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spi_xcomm = spi_master_get_devdata(master);
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spi_xcomm->i2c = i2c;
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master->num_chipselect = 16;
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master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_3WIRE;
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master->bits_per_word_mask = SPI_BPW_MASK(8);
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master->flags = SPI_MASTER_HALF_DUPLEX;
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master->transfer_one_message = spi_xcomm_transfer_one;
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master->dev.of_node = i2c->dev.of_node;
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i2c_set_clientdata(i2c, master);
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ret = devm_spi_register_master(&i2c->dev, master);
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if (ret < 0)
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spi_master_put(master);
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return ret;
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}
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static const struct i2c_device_id spi_xcomm_ids[] = {
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{ "spi-xcomm" },
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{ },
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};
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MODULE_DEVICE_TABLE(i2c, spi_xcomm_ids);
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static struct i2c_driver spi_xcomm_driver = {
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.driver = {
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.name = "spi-xcomm",
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},
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.id_table = spi_xcomm_ids,
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.probe = spi_xcomm_probe,
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};
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module_i2c_driver(spi_xcomm_driver);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
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MODULE_DESCRIPTION("Analog Devices AD-FMCOMMS1-EBZ board I2C-SPI bridge driver");
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