--- /dev/null
+/*
+ * 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" },
+ { },
+};
+
+static struct i2c_driver spi_xcomm_driver = {
+ .driver = {
+ .name = "spi-xcomm",
+ .owner = THIS_MODULE,
+ },
+ .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");
Code Review / kvmfornfv.git / blobdiff