/* * Analog Devices AD-FMCOMMS1-EBZ board I2C-SPI bridge driver * * Copyright 2012 Analog Devices Inc. * Author: Lars-Peter Clausen <lars@metafoo.de> * * Licensed under the GPL-2 or later. */ #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");