[PATCH v7 5/6] i2c: Add support for Intel LJCA USB I2C driver

Ye Xiang
2023-03-25T15:49:22Z

This patch implements the I2C function of Intel USB-I2C/GPIO/SPI adapter
device named "La Jolla Cove Adapter" (LJCA). It communicate with LJCA
I2c module with specific protocol through interfaces exported by LJCA USB
driver.

Signed-off-by: Ye Xiang <xiang.ye@intel.com>
---
drivers/i2c/busses/Kconfig | 11 ++
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-ljca.c | 355 ++++++++++++++++++++++++++++++++++
3 files changed, 367 insertions(+)
create mode 100644 drivers/i2c/busses/i2c-ljca.c

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 25eb4e8fd22f..37fed62797a9 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -1261,6 +1261,17 @@ config I2C_DLN2
This driver can also be built as a module. If so, the module
will be called i2c-dln2.

+config I2C_LJCA
+ tristate "I2C functionality of Intel La Jolla Cove Adapter"
+ depends on USB_LJCA
+ default USB_LJCA
+ help
+ If you say yes to this option, I2C functionality support of Intel
+ La Jolla Cove Adapter (LJCA) will be included.
+
+ This driver can also be built as a module. If so, the module
+ will be called i2c-ljca.
+
config I2C_CP2615
tristate "Silicon Labs CP2615 USB sound card and I2C adapter"
depends on USB
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index af56fe2c75c0..4af5b06ef288 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -133,6 +133,7 @@ obj-$(CONFIG_I2C_GXP) += i2c-gxp.o
# External I2C/SMBus adapter drivers
obj-$(CONFIG_I2C_DIOLAN_U2C) += i2c-diolan-u2c.o
obj-$(CONFIG_I2C_DLN2) += i2c-dln2.o
+obj-$(CONFIG_I2C_LJCA) += i2c-ljca.o
obj-$(CONFIG_I2C_CP2615) += i2c-cp2615.o
obj-$(CONFIG_I2C_PARPORT) += i2c-parport.o
obj-$(CONFIG_I2C_PCI1XXXX) += i2c-mchp-pci1xxxx.o
diff --git a/drivers/i2c/busses/i2c-ljca.c b/drivers/i2c/busses/i2c-ljca.c
new file mode 100644
index 000000000000..1c96f2be104d
--- /dev/null
+++ b/drivers/i2c/busses/i2c-ljca.c
@@ -0,0 +1,355 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Intel La Jolla Cove Adapter USB-I2C driver
+ *
+ * Copyright (c) 2023, Intel Corporation.
+ */
+
+#include <linux/auxiliary_bus.h>
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/dev_printk.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/usb/ljca.h>
+
+/* I2C commands */
+enum ljca_i2c_cmd {
+ LJCA_I2C_INIT = 1,
+ LJCA_I2C_XFER,
+ LJCA_I2C_START,
+ LJCA_I2C_STOP,
+ LJCA_I2C_READ,
+ LJCA_I2C_WRITE,
+};
+
+enum ljca_xfer_type {
+ LJCA_I2C_READ_XFER_TYPE,
+ LJCA_I2C_WRITE_XFER_TYPE,
+};
+
+/* I2C r/w Flags */
+#define LJCA_I2C_SLAVE_TRANSFER_WRITE 0
+#define LJCA_I2C_SLAVE_TRANSFER_READ 1
+
+/* I2C init flags */
+#define LJCA_I2C_INIT_FLAG_MODE BIT(0)
+#define LJCA_I2C_INIT_FLAG_MODE_POLLING FIELD_PREP(LJCA_I2C_INIT_FLAG_MODE, 0)
+#define LJCA_I2C_INIT_FLAG_MODE_INTERRUPT FIELD_PREP(LJCA_I2C_INIT_FLAG_MODE, 1)
+
+#define LJCA_I2C_INIT_FLAG_ADDR_16BIT BIT(0)
+
+#define LJCA_I2C_INIT_FLAG_FREQ GENMASK(2, 1)
+#define LJCA_I2C_INIT_FLAG_FREQ_100K FIELD_PREP(LJCA_I2C_INIT_FLAG_FREQ, 0)
+#define LJCA_I2C_INIT_FLAG_FREQ_400K FIELD_PREP(LJCA_I2C_INIT_FLAG_FREQ, 1)
+#define LJCA_I2C_INIT_FLAG_FREQ_1M FIELD_PREP(LJCA_I2C_INIT_FLAG_FREQ, 2)
+
+/* I2C Transfer */
+struct i2c_xfer {
+ u8 id;
+ u8 slave;
+ u16 flag; /* speed, 8/16bit addr, addr increase, etc */
+ u16 addr;
+ u16 len;
+ u8 data[];
+} __packed;
+
+/* I2C raw commands: Init/Start/Read/Write/Stop */
+struct i2c_rw_packet {
+ u8 id;
+ __le16 len;
+ u8 data[];
+} __packed;
+
+#define LJCA_I2C_BUF_SIZE 60
+#define LJCA_I2C_MAX_XFER_SIZE (LJCA_I2C_BUF_SIZE - sizeof(struct i2c_rw_packet))
+
+struct ljca_i2c_dev {
+ struct auxiliary_device *auxdev;
+ struct ljca_i2c_info *i2c_info;
+ struct i2c_adapter adap;
+
+ u8 obuf[LJCA_I2C_BUF_SIZE];
+ u8 ibuf[LJCA_I2C_BUF_SIZE];
+};
+
+static u8 ljca_i2c_format_slave_addr(u8 slave_addr, u8 type)
+{
+ return (slave_addr << 1) | (type == LJCA_I2C_READ_XFER_TYPE) ?
+ LJCA_I2C_SLAVE_TRANSFER_READ :
+ LJCA_I2C_SLAVE_TRANSFER_WRITE;
+}
+
+static int ljca_i2c_init(struct ljca_i2c_dev *ljca_i2c, u8 id)
+{
+ struct i2c_rw_packet *w_packet = (struct i2c_rw_packet *)ljca_i2c->obuf;
+
+ memset(w_packet, 0, sizeof(*w_packet));
+ w_packet->id = id;
+ w_packet->data[0] = LJCA_I2C_INIT_FLAG_FREQ_400K;
+ w_packet->len = cpu_to_le16(sizeof(*w_packet->data));
+
+ return ljca_transfer(ljca_i2c->i2c_info->ljca, LJCA_I2C_INIT, w_packet,
+ struct_size(w_packet, data, 1), NULL, NULL);
+}
+
+static int ljca_i2c_start(struct ljca_i2c_dev *ljca_i2c, u8 slave_addr, enum ljca_xfer_type type)
+{
+ struct i2c_rw_packet *w_packet = (struct i2c_rw_packet *)ljca_i2c->obuf;
+ struct i2c_rw_packet *r_packet = (struct i2c_rw_packet *)ljca_i2c->ibuf;
+ unsigned int ibuf_len = LJCA_I2C_BUF_SIZE;
+ int ret;
+ s16 rp_len;
+
+ memset(w_packet, 0, sizeof(*w_packet));
+ w_packet->id = ljca_i2c->i2c_info->id;
+ w_packet->data[0] = ljca_i2c_format_slave_addr(slave_addr, type);
+ w_packet->len = cpu_to_le16(sizeof(*w_packet->data));
+
+ ret = ljca_transfer(ljca_i2c->i2c_info->ljca, LJCA_I2C_START, w_packet,
+ struct_size(w_packet, data, 1), r_packet, &ibuf_len);
+ if (ret)
+ return ret;
+
+ if (ibuf_len < sizeof(*r_packet))
+ return -EIO;
+
+ rp_len = le16_to_cpu(r_packet->len);
+ if (rp_len < 0 || r_packet->id != w_packet->id) {
+ dev_err(&ljca_i2c->adap.dev, "i2c start failed len:%d id:%d %d\n", rp_len,
+ r_packet->id, w_packet->id);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int ljca_i2c_stop(struct ljca_i2c_dev *ljca_i2c, u8 slave_addr)
+{
+ struct i2c_rw_packet *w_packet = (struct i2c_rw_packet *)ljca_i2c->obuf;
+ struct i2c_rw_packet *r_packet = (struct i2c_rw_packet *)ljca_i2c->ibuf;
+ unsigned int ibuf_len = LJCA_I2C_BUF_SIZE;
+ int ret;
+ s16 rp_len;
+
+ memset(w_packet, 0, sizeof(*w_packet));
+ w_packet->id = ljca_i2c->i2c_info->id;
+ w_packet->data[0] = 0;
+ w_packet->len = cpu_to_le16(sizeof(*w_packet->data));
+
+ ret = ljca_transfer(ljca_i2c->i2c_info->ljca, LJCA_I2C_STOP, w_packet,
+ struct_size(w_packet, data, 1), r_packet, &ibuf_len);
+ if (ret)
+ return ret;
+
+ if (ibuf_len < sizeof(*r_packet))
+ return -EIO;
+
+ rp_len = le16_to_cpu(r_packet->len);
+ if (rp_len < 0 || r_packet->id != w_packet->id) {
+ dev_err(&ljca_i2c->adap.dev, "i2c stop failed len:%d id:%d %d\n", rp_len,
+ r_packet->id, w_packet->id);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int ljca_i2c_pure_read(struct ljca_i2c_dev *ljca_i2c, u8 *data, u8 len)
+{
+ struct i2c_rw_packet *w_packet = (struct i2c_rw_packet *)ljca_i2c->obuf;
+ struct i2c_rw_packet *r_packet = (struct i2c_rw_packet *)ljca_i2c->ibuf;
+ unsigned int ibuf_len = LJCA_I2C_BUF_SIZE;
+ int ret;
+ s16 rp_len;
+
+ if (len > LJCA_I2C_MAX_XFER_SIZE)
+ return -EINVAL;
+
+ memset(w_packet, 0, sizeof(*w_packet));
+ w_packet->id = ljca_i2c->i2c_info->id;
+ w_packet->len = cpu_to_le16(len);
+ w_packet->data[0] = 0;
+
+ ret = ljca_transfer(ljca_i2c->i2c_info->ljca, LJCA_I2C_READ, w_packet,
+ struct_size(w_packet, data, 1), r_packet, &ibuf_len);
+ if (ret)
+ return ret;
+
+ if (ibuf_len < sizeof(*r_packet))
+ return -EIO;
+
+ rp_len = le16_to_cpu(r_packet->len);
+ if (rp_len != len || r_packet->id != w_packet->id) {
+ dev_err(&ljca_i2c->adap.dev, "i2c raw read failed len:%d id:%d %d\n", rp_len,
+ r_packet->id, w_packet->id);
+ return -EIO;
+ }
+
+ memcpy(data, r_packet->data, len);
+
+ return 0;
+}
+
+static int ljca_i2c_read(struct ljca_i2c_dev *ljca_i2c, u8 slave_addr, u8 *data,
+ u8 len)
+{
+ int ret;
+
+ ret = ljca_i2c_start(ljca_i2c, slave_addr, LJCA_I2C_READ_XFER_TYPE);
+ if (ret)
+ goto out_stop;
+
+ ret = ljca_i2c_pure_read(ljca_i2c, data, len);
+
+out_stop:
+ ljca_i2c_stop(ljca_i2c, slave_addr);
+
+ return ret;
+}
+
+static int ljca_i2c_pure_write(struct ljca_i2c_dev *ljca_i2c, u8 *data, u8 len)
+{
+ struct i2c_rw_packet *w_packet = (struct i2c_rw_packet *)ljca_i2c->obuf;
+ struct i2c_rw_packet *r_packet = (struct i2c_rw_packet *)ljca_i2c->ibuf;
+ unsigned int ibuf_len = LJCA_I2C_BUF_SIZE;
+ s16 rplen;
+ int ret;
+
+ if (len > LJCA_I2C_MAX_XFER_SIZE)
+ return -EINVAL;
+
+ memset(w_packet, 0, sizeof(*w_packet));
+ w_packet->id = ljca_i2c->i2c_info->id;
+ w_packet->len = cpu_to_le16(len);
+ memcpy(w_packet->data, data, len);
+
+ ret = ljca_transfer(ljca_i2c->i2c_info->ljca, LJCA_I2C_WRITE, w_packet,
+ struct_size(w_packet, data, len), r_packet, &ibuf_len);
+ if (ret)
+ return ret;
+
+ if (ibuf_len < sizeof(*r_packet))
+ return -EIO;
+
+ rplen = le16_to_cpu(r_packet->len);
+ if (rplen != len || r_packet->id != w_packet->id) {
+ dev_err(&ljca_i2c->adap.dev, "i2c write failed len:%d id:%d/%d\n", rplen,
+ r_packet->id, w_packet->id);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int ljca_i2c_write(struct ljca_i2c_dev *ljca_i2c, u8 slave_addr, u8 *data, u8 len)
+{
+ int ret;
+
+ if (!data)
+ return -EINVAL;
+
+ ret = ljca_i2c_start(ljca_i2c, slave_addr, LJCA_I2C_WRITE_XFER_TYPE);
+ if (ret)
+ goto out_stop;
+
+ ret = ljca_i2c_pure_write(ljca_i2c, data, len);
+
+out_stop:
+ ljca_i2c_stop(ljca_i2c, slave_addr);
+
+ return ret;
+}
+
+static int ljca_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msg, int num)
+{
+ struct ljca_i2c_dev *ljca_i2c;
+ struct i2c_msg *cur_msg;
+ int i, ret;
+
+ ljca_i2c = i2c_get_adapdata(adapter);
+ if (!ljca_i2c)
+ return -EINVAL;
+
+ for (i = 0; i < num; i++) {
+ cur_msg = &msg[i];
+ if (cur_msg->flags & I2C_M_RD)
+ ret = ljca_i2c_read(ljca_i2c, cur_msg->addr, cur_msg->buf, cur_msg->len);
+ else
+ ret = ljca_i2c_write(ljca_i2c, cur_msg->addr, cur_msg->buf, cur_msg->len);
+
+ if (ret)
+ return ret;
+ }
+
+ return num;
+}
+
+static u32 ljca_i2c_func(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_adapter_quirks ljca_i2c_quirks = {
+ .max_read_len = LJCA_I2C_MAX_XFER_SIZE,
+ .max_write_len = LJCA_I2C_MAX_XFER_SIZE,
+};
+
+static const struct i2c_algorithm ljca_i2c_algo = {
+ .master_xfer = ljca_i2c_xfer,
+ .functionality = ljca_i2c_func,
+};
+
+static int ljca_i2c_probe(struct auxiliary_device *auxdev,
+ const struct auxiliary_device_id *aux_dev_id)
+{
+ struct ljca_i2c_dev *ljca_i2c;
+ int ret;
+
+ ljca_i2c = devm_kzalloc(&auxdev->dev, sizeof(*ljca_i2c), GFP_KERNEL);
+ if (!ljca_i2c)
+ return -ENOMEM;
+
+ ljca_i2c->auxdev = auxdev;
+ ljca_i2c->i2c_info = dev_get_platdata(&auxdev->dev);
+ ljca_i2c->adap.owner = THIS_MODULE;
+ ljca_i2c->adap.class = I2C_CLASS_HWMON;
+ ljca_i2c->adap.algo = &ljca_i2c_algo;
+ ljca_i2c->adap.quirks = &ljca_i2c_quirks;
+ ljca_i2c->adap.dev.parent = &auxdev->dev;
+ device_set_node(&ljca_i2c->adap.dev, dev_fwnode(&auxdev->dev));
+ i2c_set_adapdata(&ljca_i2c->adap, ljca_i2c);
+ snprintf(ljca_i2c->adap.name, sizeof(ljca_i2c->adap.name), "%s-%s-%d",
+ dev_name(&auxdev->dev), dev_name(auxdev->dev.parent),
+ ljca_i2c->i2c_info->id);
+
+ auxiliary_set_drvdata(auxdev, ljca_i2c);
+
+ ret = ljca_i2c_init(ljca_i2c, ljca_i2c->i2c_info->id);
+ if (ret) {
+ dev_err(&auxdev->dev, "i2c init failed id:%d\n", ljca_i2c->i2c_info->id);
+ return -EIO;
+ }
+
+ return devm_i2c_add_adapter(&auxdev->dev, &ljca_i2c->adap);
+}
+
+#define LJCA_I2C_DRV_NAME "ljca.ljca-i2c"
+static const struct auxiliary_device_id ljca_i2c_id_table[] = {
+ { LJCA_I2C_DRV_NAME, 0 },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(auxiliary, ljca_i2c_id_table);
+
+static struct auxiliary_driver ljca_i2c_driver = {
+ .probe = ljca_i2c_probe,
+ .id_table = ljca_i2c_id_table,
+};
+module_auxiliary_driver(ljca_i2c_driver);
+
+MODULE_AUTHOR("Ye Xiang <xiang.ye@intel.com>");
+MODULE_AUTHOR("Wang Zhifeng <zhifeng.wang@intel.com>");
+MODULE_AUTHOR("Zhang Lixu <lixu.zhang@intel.com>");
+MODULE_DESCRIPTION("Intel La Jolla Cove Adapter USB-I2C driver");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(LJCA);
--
2.34.1