[PATCH net-next v2 2/6] net: txgbe: Implement I2C bus master driver

Jiawen Wu
2023-04-11T09:29:24Z

Implement I2C bus driver to send and receive I2C messages.

This I2C license the IP of Synopsys Designware, but without interrupt
support on the hardware design. It seems that polling mode needs to be
added in Synopsys Designware I2C driver. But currently it can only be
driven by this I2C bus master driver.

Signed-off-by: Jiawen Wu <jiawenwu@trustnetic.com>
---
drivers/net/ethernet/wangxun/Kconfig | 1 +
.../net/ethernet/wangxun/txgbe/txgbe_phy.c | 153 ++++++++++++++++++
.../net/ethernet/wangxun/txgbe/txgbe_type.h | 23 +++
3 files changed, 177 insertions(+)

diff --git a/drivers/net/ethernet/wangxun/Kconfig b/drivers/net/ethernet/wangxun/Kconfig
index c9d88673d306..8cbf0dd48a2c 100644
--- a/drivers/net/ethernet/wangxun/Kconfig
+++ b/drivers/net/ethernet/wangxun/Kconfig
@@ -41,6 +41,7 @@ config TXGBE
tristate "Wangxun(R) 10GbE PCI Express adapters support"
depends on PCI
select LIBWX
+ select I2C
help
This driver supports Wangxun(R) 10GbE PCI Express family of
adapters.
diff --git a/drivers/net/ethernet/wangxun/txgbe/txgbe_phy.c b/drivers/net/ethernet/wangxun/txgbe/txgbe_phy.c
index 86d5e0647d5e..2721da1625e0 100644
--- a/drivers/net/ethernet/wangxun/txgbe/txgbe_phy.c
+++ b/drivers/net/ethernet/wangxun/txgbe/txgbe_phy.c
@@ -2,9 +2,12 @@
/* Copyright (c) 2015 - 2023 Beijing WangXun Technology Co., Ltd. */

#include <linux/gpio/property.h>
+#include <linux/iopoll.h>
+#include <linux/i2c.h>
#include <linux/pci.h>

#include "../libwx/wx_type.h"
+#include "../libwx/wx_hw.h"
#include "txgbe_type.h"
#include "txgbe_phy.h"

@@ -67,6 +70,142 @@ static int txgbe_swnodes_register(struct txgbe *txgbe)
return software_node_register_node_group(nodes->group);
}

+static void txgbe_i2c_start(struct wx *wx, u16 dev_addr)
+{
+ wr32(wx, TXGBE_I2C_ENABLE, 0);
+
+ wr32(wx, TXGBE_I2C_CON,
+ (TXGBE_I2C_CON_MASTER_MODE |
+ TXGBE_I2C_CON_SPEED(1) |
+ TXGBE_I2C_CON_RESTART_EN |
+ TXGBE_I2C_CON_SLAVE_DISABLE));
+ wr32(wx, TXGBE_I2C_TAR, dev_addr);
+ wr32(wx, TXGBE_I2C_SS_SCL_HCNT, 600);
+ wr32(wx, TXGBE_I2C_SS_SCL_LCNT, 600);
+ wr32(wx, TXGBE_I2C_RX_TL, 0); /* 1byte for rx full signal */
+ wr32(wx, TXGBE_I2C_TX_TL, 4);
+ wr32(wx, TXGBE_I2C_SCL_STUCK_TIMEOUT, 0xFFFFFF);
+ wr32(wx, TXGBE_I2C_SDA_STUCK_TIMEOUT, 0xFFFFFF);
+
+ wr32(wx, TXGBE_I2C_INTR_MASK, 0);
+ wr32(wx, TXGBE_I2C_ENABLE, 1);
+}
+
+static int txgbe_i2c_poll_intr(struct wx *wx, u16 intr)
+{
+ u16 val;
+
+ return read_poll_timeout(rd32, val, (val & intr) == intr,
+ 100, 1000, false, wx,
+ TXGBE_I2C_RAW_INTR_STAT);
+}
+
+static int txgbe_read_i2c_bytes(struct wx *wx, u8 dev_addr, struct i2c_msg *msg)
+{
+ int err, i;
+
+ txgbe_i2c_start(wx, msg->addr);
+
+ for (i = 0; i < msg->len; i++) {
+ /* wait tx empty */
+ err = txgbe_i2c_poll_intr(wx, TXGBE_I2C_INTR_STAT_TEMP);
+ if (err)
+ return err;
+
+ /* read data */
+ wr32(wx, TXGBE_I2C_DATA_CMD,
+ (dev_addr + i) | TXGBE_I2C_DATA_CMD_STOP);
+ wr32(wx, TXGBE_I2C_DATA_CMD,
+ TXGBE_I2C_DATA_CMD_READ | TXGBE_I2C_DATA_CMD_STOP);
+
+ /* wait for read complete */
+ err = txgbe_i2c_poll_intr(wx, TXGBE_I2C_INTR_STAT_RFUL);
+ if (err)
+ return err;
+
+ msg->buf[i] = 0xFF & rd32(wx, TXGBE_I2C_DATA_CMD);
+ }
+
+ return 0;
+}
+
+static int txgbe_write_i2c_bytes(struct wx *wx, struct i2c_msg *msg)
+{
+ int err, i;
+
+ txgbe_i2c_start(wx, msg->addr);
+
+ for (i = 0; i < msg->len; i++) {
+ /* wait tx empty */
+ err = txgbe_i2c_poll_intr(wx, TXGBE_I2C_INTR_STAT_TEMP);
+ if (err)
+ return err;
+
+ /* write data */
+ wr32(wx, TXGBE_I2C_DATA_CMD, msg->buf[i]);
+ if (i == (msg->len - 1))
+ wr32(wx, TXGBE_I2C_DATA_CMD, TXGBE_I2C_DATA_CMD_STOP);
+ }
+
+ return 0;
+}
+
+static int txgbe_i2c_xfer(struct i2c_adapter *i2c_adap,
+ struct i2c_msg *msg, int num_msgs)
+{
+ struct wx *wx = i2c_get_adapdata(i2c_adap);
+ u8 dev_addr = msg[0].buf[0];
+ int i, ret;
+
+ for (i = 0; i < num_msgs; i++) {
+ if (msg[i].flags & I2C_M_RD)
+ ret = txgbe_read_i2c_bytes(wx, dev_addr, &msg[i]);
+ else
+ ret = txgbe_write_i2c_bytes(wx, &msg[i]);
+
+ if (ret)
+ return ret;
+ }
+
+ return num_msgs;
+}
+
+static u32 txgbe_i2c_func(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C;
+}
+
+static const struct i2c_algorithm txgbe_i2c_algo = {
+ .master_xfer = txgbe_i2c_xfer,
+ .functionality = txgbe_i2c_func,
+};
+
+static int txgbe_i2c_adapter_add(struct txgbe *txgbe)
+{
+ struct pci_dev *pdev = txgbe->wx->pdev;
+ struct i2c_adapter *i2c_adap;
+ int ret;
+
+ i2c_adap = devm_kzalloc(&pdev->dev, sizeof(*i2c_adap), GFP_KERNEL);
+ if (!i2c_adap)
+ return -ENOMEM;
+
+ i2c_adap->owner = THIS_MODULE;
+ i2c_adap->algo = &txgbe_i2c_algo;
+ i2c_adap->dev.parent = &pdev->dev;
+ i2c_adap->dev.fwnode = software_node_fwnode(txgbe->nodes.group[SWNODE_I2C]);
+ strscpy(i2c_adap->name, "txgbe_i2c", sizeof(i2c_adap->name));
+
+ i2c_set_adapdata(i2c_adap, txgbe->wx);
+ ret = i2c_add_adapter(i2c_adap);
+ if (ret)
+ return ret;
+
+ txgbe->i2c_adap = i2c_adap;
+
+ return 0;
+}
+
int txgbe_init_phy(struct txgbe *txgbe)
{
int ret;
@@ -77,10 +216,24 @@ int txgbe_init_phy(struct txgbe *txgbe)
return ret;
}

+ ret = txgbe_i2c_adapter_add(txgbe);
+ if (ret) {
+ wx_err(txgbe->wx, "failed to init i2c interface: %d\n", ret);
+ goto err;
+ }
+
return 0;
+
+err:
+ txgbe_remove_phy(txgbe);
+
+ return ret;
}

void txgbe_remove_phy(struct txgbe *txgbe)
{
+ if (txgbe->i2c_adap)
+ i2c_del_adapter(txgbe->i2c_adap);
+
software_node_unregister_node_group(txgbe->nodes.group);
}
diff --git a/drivers/net/ethernet/wangxun/txgbe/txgbe_type.h b/drivers/net/ethernet/wangxun/txgbe/txgbe_type.h
index d30684378f4e..6c02af196157 100644
--- a/drivers/net/ethernet/wangxun/txgbe/txgbe_type.h
+++ b/drivers/net/ethernet/wangxun/txgbe/txgbe_type.h
@@ -55,6 +55,28 @@
#define TXGBE_TS_CTL 0x10300
#define TXGBE_TS_CTL_EVAL_MD BIT(31)

+/* I2C registers */
+#define TXGBE_I2C_CON 0x14900 /* I2C Control */
+#define TXGBE_I2C_CON_SLAVE_DISABLE BIT(6)
+#define TXGBE_I2C_CON_RESTART_EN BIT(5)
+#define TXGBE_I2C_CON_SPEED(_v) FIELD_PREP(GENMASK(2, 1), _v)
+#define TXGBE_I2C_CON_MASTER_MODE BIT(0)
+#define TXGBE_I2C_TAR 0x14904 /* I2C Target Address */
+#define TXGBE_I2C_DATA_CMD 0x14910 /* I2C Rx/Tx Data Buf and Cmd */
+#define TXGBE_I2C_DATA_CMD_STOP BIT(9)
+#define TXGBE_I2C_DATA_CMD_READ BIT(8)
+#define TXGBE_I2C_SS_SCL_HCNT 0x14914
+#define TXGBE_I2C_SS_SCL_LCNT 0x14918
+#define TXGBE_I2C_INTR_MASK 0x14930 /* I2C Interrupt Mask */
+#define TXGBE_I2C_RAW_INTR_STAT 0x14934 /* I2C Raw Interrupt Status */
+#define TXGBE_I2C_INTR_STAT_RFUL BIT(2)
+#define TXGBE_I2C_INTR_STAT_TEMP BIT(4)
+#define TXGBE_I2C_RX_TL 0x14938 /* I2C Receive FIFO Threshold */
+#define TXGBE_I2C_TX_TL 0x1493C /* I2C TX FIFO Threshold */
+#define TXGBE_I2C_ENABLE 0x1496C /* I2C Enable */
+#define TXGBE_I2C_SCL_STUCK_TIMEOUT 0x149AC
+#define TXGBE_I2C_SDA_STUCK_TIMEOUT 0x149B0
+
/* Part Number String Length */
#define TXGBE_PBANUM_LENGTH 32

@@ -139,6 +161,7 @@ struct txgbe_nodes {
struct txgbe {
struct wx *wx;
struct txgbe_nodes nodes;
+ struct i2c_adapter *i2c_adap;
};

#endif /* _TXGBE_TYPE_H_ */
--
2.27.0