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251 lines
5.8 KiB
251 lines
5.8 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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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 <[email protected]> |
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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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spi_transfer_delay_exec(t); |
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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 <[email protected]>"); |
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MODULE_DESCRIPTION("Analog Devices AD-FMCOMMS1-EBZ board I2C-SPI bridge driver");
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