| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* |
| * Analog Devices AD-FMCOMMS1-EBZ board I2C-SPI bridge driver |
| * |
| * Copyright 2012 Analog Devices Inc. |
| * Author: Lars-Peter Clausen <lars@metafoo.de> |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/delay.h> |
| #include <linux/i2c.h> |
| #include <linux/spi/spi.h> |
| #include <asm/unaligned.h> |
| |
| #define SPI_XCOMM_SETTINGS_LEN_OFFSET 10 |
| #define SPI_XCOMM_SETTINGS_3WIRE BIT(6) |
| #define SPI_XCOMM_SETTINGS_CS_HIGH BIT(5) |
| #define SPI_XCOMM_SETTINGS_SAMPLE_END BIT(4) |
| #define SPI_XCOMM_SETTINGS_CPHA BIT(3) |
| #define SPI_XCOMM_SETTINGS_CPOL BIT(2) |
| #define SPI_XCOMM_SETTINGS_CLOCK_DIV_MASK 0x3 |
| #define SPI_XCOMM_SETTINGS_CLOCK_DIV_64 0x2 |
| #define SPI_XCOMM_SETTINGS_CLOCK_DIV_16 0x1 |
| #define SPI_XCOMM_SETTINGS_CLOCK_DIV_4 0x0 |
| |
| #define SPI_XCOMM_CMD_UPDATE_CONFIG 0x03 |
| #define SPI_XCOMM_CMD_WRITE 0x04 |
| |
| #define SPI_XCOMM_CLOCK 48000000 |
| |
| struct spi_xcomm { |
| struct i2c_client *i2c; |
| |
| uint16_t settings; |
| uint16_t chipselect; |
| |
| unsigned int current_speed; |
| |
| uint8_t buf[63]; |
| }; |
| |
| static int spi_xcomm_sync_config(struct spi_xcomm *spi_xcomm, unsigned int len) |
| { |
| uint16_t settings; |
| uint8_t *buf = spi_xcomm->buf; |
| |
| settings = spi_xcomm->settings; |
| settings |= len << SPI_XCOMM_SETTINGS_LEN_OFFSET; |
| |
| buf[0] = SPI_XCOMM_CMD_UPDATE_CONFIG; |
| put_unaligned_be16(settings, &buf[1]); |
| put_unaligned_be16(spi_xcomm->chipselect, &buf[3]); |
| |
| return i2c_master_send(spi_xcomm->i2c, buf, 5); |
| } |
| |
| static void spi_xcomm_chipselect(struct spi_xcomm *spi_xcomm, |
| struct spi_device *spi, int is_active) |
| { |
| unsigned long cs = spi->chip_select; |
| uint16_t chipselect = spi_xcomm->chipselect; |
| |
| if (is_active) |
| chipselect |= BIT(cs); |
| else |
| chipselect &= ~BIT(cs); |
| |
| spi_xcomm->chipselect = chipselect; |
| } |
| |
| static int spi_xcomm_setup_transfer(struct spi_xcomm *spi_xcomm, |
| struct spi_device *spi, struct spi_transfer *t, unsigned int *settings) |
| { |
| if (t->len > 62) |
| return -EINVAL; |
| |
| if (t->speed_hz != spi_xcomm->current_speed) { |
| unsigned int divider; |
| |
| divider = DIV_ROUND_UP(SPI_XCOMM_CLOCK, t->speed_hz); |
| if (divider >= 64) |
| *settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_64; |
| else if (divider >= 16) |
| *settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_16; |
| else |
| *settings |= SPI_XCOMM_SETTINGS_CLOCK_DIV_4; |
| |
| spi_xcomm->current_speed = t->speed_hz; |
| } |
| |
| if (spi->mode & SPI_CPOL) |
| *settings |= SPI_XCOMM_SETTINGS_CPOL; |
| else |
| *settings &= ~SPI_XCOMM_SETTINGS_CPOL; |
| |
| if (spi->mode & SPI_CPHA) |
| *settings &= ~SPI_XCOMM_SETTINGS_CPHA; |
| else |
| *settings |= SPI_XCOMM_SETTINGS_CPHA; |
| |
| if (spi->mode & SPI_3WIRE) |
| *settings |= SPI_XCOMM_SETTINGS_3WIRE; |
| else |
| *settings &= ~SPI_XCOMM_SETTINGS_3WIRE; |
| |
| return 0; |
| } |
| |
| static int spi_xcomm_txrx_bufs(struct spi_xcomm *spi_xcomm, |
| struct spi_device *spi, struct spi_transfer *t) |
| { |
| int ret; |
| |
| if (t->tx_buf) { |
| spi_xcomm->buf[0] = SPI_XCOMM_CMD_WRITE; |
| memcpy(spi_xcomm->buf + 1, t->tx_buf, t->len); |
| |
| ret = i2c_master_send(spi_xcomm->i2c, spi_xcomm->buf, t->len + 1); |
| if (ret < 0) |
| return ret; |
| else if (ret != t->len + 1) |
| return -EIO; |
| } else if (t->rx_buf) { |
| ret = i2c_master_recv(spi_xcomm->i2c, t->rx_buf, t->len); |
| if (ret < 0) |
| return ret; |
| else if (ret != t->len) |
| return -EIO; |
| } |
| |
| return t->len; |
| } |
| |
| static int spi_xcomm_transfer_one(struct spi_master *master, |
| struct spi_message *msg) |
| { |
| struct spi_xcomm *spi_xcomm = spi_master_get_devdata(master); |
| unsigned int settings = spi_xcomm->settings; |
| struct spi_device *spi = msg->spi; |
| unsigned cs_change = 0; |
| struct spi_transfer *t; |
| bool is_first = true; |
| int status = 0; |
| bool is_last; |
| |
| spi_xcomm_chipselect(spi_xcomm, spi, true); |
| |
| list_for_each_entry(t, &msg->transfers, transfer_list) { |
| |
| if (!t->tx_buf && !t->rx_buf && t->len) { |
| status = -EINVAL; |
| break; |
| } |
| |
| status = spi_xcomm_setup_transfer(spi_xcomm, spi, t, &settings); |
| if (status < 0) |
| break; |
| |
| is_last = list_is_last(&t->transfer_list, &msg->transfers); |
| cs_change = t->cs_change; |
| |
| if (cs_change ^ is_last) |
| settings |= BIT(5); |
| else |
| settings &= ~BIT(5); |
| |
| if (t->rx_buf) { |
| spi_xcomm->settings = settings; |
| status = spi_xcomm_sync_config(spi_xcomm, t->len); |
| if (status < 0) |
| break; |
| } else if (settings != spi_xcomm->settings || is_first) { |
| spi_xcomm->settings = settings; |
| status = spi_xcomm_sync_config(spi_xcomm, 0); |
| if (status < 0) |
| break; |
| } |
| |
| if (t->len) { |
| status = spi_xcomm_txrx_bufs(spi_xcomm, spi, t); |
| |
| if (status < 0) |
| break; |
| |
| if (status > 0) |
| msg->actual_length += status; |
| } |
| status = 0; |
| |
| if (t->delay_usecs) |
| udelay(t->delay_usecs); |
| |
| is_first = false; |
| } |
| |
| if (status != 0 || !cs_change) |
| spi_xcomm_chipselect(spi_xcomm, spi, false); |
| |
| msg->status = status; |
| spi_finalize_current_message(master); |
| |
| return status; |
| } |
| |
| static int spi_xcomm_probe(struct i2c_client *i2c, |
| const struct i2c_device_id *id) |
| { |
| struct spi_xcomm *spi_xcomm; |
| struct spi_master *master; |
| int ret; |
| |
| master = spi_alloc_master(&i2c->dev, sizeof(*spi_xcomm)); |
| if (!master) |
| return -ENOMEM; |
| |
| spi_xcomm = spi_master_get_devdata(master); |
| spi_xcomm->i2c = i2c; |
| |
| master->num_chipselect = 16; |
| master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_3WIRE; |
| master->bits_per_word_mask = SPI_BPW_MASK(8); |
| master->flags = SPI_MASTER_HALF_DUPLEX; |
| master->transfer_one_message = spi_xcomm_transfer_one; |
| master->dev.of_node = i2c->dev.of_node; |
| i2c_set_clientdata(i2c, master); |
| |
| ret = devm_spi_register_master(&i2c->dev, master); |
| if (ret < 0) |
| spi_master_put(master); |
| |
| return ret; |
| } |
| |
| static const struct i2c_device_id spi_xcomm_ids[] = { |
| { "spi-xcomm" }, |
| { }, |
| }; |
| MODULE_DEVICE_TABLE(i2c, spi_xcomm_ids); |
| |
| static struct i2c_driver spi_xcomm_driver = { |
| .driver = { |
| .name = "spi-xcomm", |
| }, |
| .id_table = spi_xcomm_ids, |
| .probe = spi_xcomm_probe, |
| }; |
| module_i2c_driver(spi_xcomm_driver); |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); |
| MODULE_DESCRIPTION("Analog Devices AD-FMCOMMS1-EBZ board I2C-SPI bridge driver"); |