--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (C) 2022 Hewlett-Packard Enterprise Development Company, L.P. */
+
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/regmap.h>
+#include <linux/mfd/syscon.h>
+
+#define GXP_MAX_I2C_ENGINE 10
+static const char * const gxp_i2c_name[] = {
+ "gxp-i2c0", "gxp-i2c1", "gxp-i2c2", "gxp-i2c3",
+ "gxp-i2c4", "gxp-i2c5", "gxp-i2c6", "gxp-i2c7",
+ "gxp-i2c8", "gxp-i2c9" };
+
+/* GXP I2C Global interrupt status/enable register*/
+#define GXP_I2CINTSTAT 0x00
+#define GXP_I2CINTEN 0x04
+
+/* GXP I2C registers */
+#define GXP_I2CSTAT 0x00
+#define MASK_STOP_EVENT 0x20
+#define MASK_ACK 0x08
+#define MASK_RW 0x04
+#define GXP_I2CEVTERR 0x01
+#define MASK_SLAVE_CMD_EVENT 0x01
+#define MASK_SLAVE_DATA_EVENT 0x02
+#define MASK_MASTER_EVENT 0x10
+#define GXP_I2CSNPDAT 0x02
+#define GXP_I2CMCMD 0x04
+#define GXP_I2CSCMD 0x06
+#define GXP_I2CSNPAA 0x09
+#define GXP_I2CADVFEAT 0x0A
+#define GXP_I2COWNADR 0x0B
+#define GXP_I2CFREQDIV 0x0C
+#define GXP_I2CFLTFAIR 0x0D
+#define GXP_I2CTMOEDG 0x0E
+#define GXP_I2CCYCTIM 0x0F
+
+/* I2CSCMD Bits */
+#define SNOOP_EVT_CLR 0x80
+#define SLAVE_EVT_CLR 0x40
+#define SNOOP_EVT_MASK 0x20
+#define SLAVE_EVT_MASK 0x10
+#define SLAVE_ACK_ENAB 0x08
+#define SLAVE_EVT_STALL 0x01
+
+/* I2CMCMD Bits */
+#define MASTER_EVT_CLR 0x80
+#define MASTER_ACK_ENAB 0x08
+#define RW_CMD 0x04
+#define STOP_CMD 0x02
+#define START_CMD 0x01
+
+/* I2CTMOEDG value */
+#define GXP_DATA_EDGE_RST_CTRL 0x0a /* 30ns */
+
+/* I2CFLTFAIR Bits */
+#define FILTER_CNT 0x30
+#define FAIRNESS_CNT 0x02
+
+enum {
+ GXP_I2C_IDLE = 0,
+ GXP_I2C_ADDR_PHASE,
+ GXP_I2C_RDATA_PHASE,
+ GXP_I2C_WDATA_PHASE,
+ GXP_I2C_ADDR_NACK,
+ GXP_I2C_DATA_NACK,
+ GXP_I2C_ERROR,
+ GXP_I2C_COMP
+};
+
+struct gxp_i2c_drvdata {
+ struct device *dev;
+ void __iomem *base;
+ struct i2c_timings t;
+ u32 engine;
+ int irq;
+ struct completion completion;
+ struct i2c_adapter adapter;
+ struct i2c_msg *curr_msg;
+ int msgs_remaining;
+ int msgs_num;
+ u8 *buf;
+ size_t buf_remaining;
+ unsigned char state;
+ struct i2c_client *slave;
+ unsigned char stopped;
+};
+
+static struct regmap *i2cg_map;
+
+static void gxp_i2c_start(struct gxp_i2c_drvdata *drvdata)
+{
+ u16 value;
+
+ drvdata->buf = drvdata->curr_msg->buf;
+ drvdata->buf_remaining = drvdata->curr_msg->len;
+
+ /* Note: Address in struct i2c_msg is 7 bits */
+ value = drvdata->curr_msg->addr << 9;
+
+ /* Read or Write */
+ value |= drvdata->curr_msg->flags & I2C_M_RD ? RW_CMD | START_CMD : START_CMD;
+
+ drvdata->state = GXP_I2C_ADDR_PHASE;
+ writew(value, drvdata->base + GXP_I2CMCMD);
+}
+
+static int gxp_i2c_master_xfer(struct i2c_adapter *adapter,
+ struct i2c_msg *msgs, int num)
+{
+ int ret;
+ struct gxp_i2c_drvdata *drvdata = i2c_get_adapdata(adapter);
+ unsigned long time_left;
+
+ drvdata->msgs_remaining = num;
+ drvdata->curr_msg = msgs;
+ drvdata->msgs_num = num;
+ reinit_completion(&drvdata->completion);
+
+ gxp_i2c_start(drvdata);
+
+ time_left = wait_for_completion_timeout(&drvdata->completion,
+ adapter->timeout);
+ ret = num - drvdata->msgs_remaining;
+ if (time_left == 0) {
+ switch (drvdata->state) {
+ case GXP_I2C_WDATA_PHASE:
+ break;
+ case GXP_I2C_RDATA_PHASE:
+ break;
+ case GXP_I2C_ADDR_PHASE:
+ break;
+ default:
+ break;
+ }
+ return -ETIMEDOUT;
+ }
+
+ if (drvdata->state == GXP_I2C_ADDR_NACK ||
+ drvdata->state == GXP_I2C_DATA_NACK)
+ return -EIO;
+
+ return ret;
+}
+
+static u32 gxp_i2c_func(struct i2c_adapter *adap)
+{
+ if (IS_ENABLED(CONFIG_I2C_SLAVE))
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SLAVE;
+
+ return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+static int gxp_i2c_reg_slave(struct i2c_client *slave)
+{
+ struct gxp_i2c_drvdata *drvdata = i2c_get_adapdata(slave->adapter);
+
+ if (drvdata->slave)
+ return -EBUSY;
+
+ if (slave->flags & I2C_CLIENT_TEN)
+ return -EAFNOSUPPORT;
+
+ drvdata->slave = slave;
+
+ writeb(slave->addr << 1, drvdata->base + GXP_I2COWNADR);
+ writeb(SLAVE_EVT_CLR | SNOOP_EVT_MASK | SLAVE_ACK_ENAB |
+ SLAVE_EVT_STALL, drvdata->base + GXP_I2CSCMD);
+
+ return 0;
+}
+
+static int gxp_i2c_unreg_slave(struct i2c_client *slave)
+{
+ struct gxp_i2c_drvdata *drvdata = i2c_get_adapdata(slave->adapter);
+
+ WARN_ON(!drvdata->slave);
+
+ writeb(0x00, drvdata->base + GXP_I2COWNADR);
+ writeb(SNOOP_EVT_CLR | SLAVE_EVT_CLR | SNOOP_EVT_MASK |
+ SLAVE_EVT_MASK, drvdata->base + GXP_I2CSCMD);
+
+ drvdata->slave = NULL;
+
+ return 0;
+}
+#endif
+
+static const struct i2c_algorithm gxp_i2c_algo = {
+ .master_xfer = gxp_i2c_master_xfer,
+ .functionality = gxp_i2c_func,
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+ .reg_slave = gxp_i2c_reg_slave,
+ .unreg_slave = gxp_i2c_unreg_slave,
+#endif
+};
+
+static void gxp_i2c_stop(struct gxp_i2c_drvdata *drvdata)
+{
+ /* Clear event and send stop */
+ writeb(MASTER_EVT_CLR | STOP_CMD, drvdata->base + GXP_I2CMCMD);
+
+ complete(&drvdata->completion);
+}
+
+static void gxp_i2c_restart(struct gxp_i2c_drvdata *drvdata)
+{
+ u16 value;
+
+ drvdata->buf = drvdata->curr_msg->buf;
+ drvdata->buf_remaining = drvdata->curr_msg->len;
+
+ value = drvdata->curr_msg->addr << 9;
+
+ if (drvdata->curr_msg->flags & I2C_M_RD) {
+ /* Read and clear master event */
+ value |= MASTER_EVT_CLR | RW_CMD | START_CMD;
+ } else {
+ /* Write and clear master event */
+ value |= MASTER_EVT_CLR | START_CMD;
+ }
+
+ drvdata->state = GXP_I2C_ADDR_PHASE;
+
+ writew(value, drvdata->base + GXP_I2CMCMD);
+}
+
+static void gxp_i2c_chk_addr_ack(struct gxp_i2c_drvdata *drvdata)
+{
+ u16 value;
+
+ value = readb(drvdata->base + GXP_I2CSTAT);
+ if (!(value & MASK_ACK)) {
+ /* Got no ack, stop */
+ drvdata->state = GXP_I2C_ADDR_NACK;
+ gxp_i2c_stop(drvdata);
+ return;
+ }
+
+ if (drvdata->curr_msg->flags & I2C_M_RD) {
+ /* Start to read data from slave */
+ if (drvdata->buf_remaining == 0) {
+ /* No more data to read, stop */
+ drvdata->msgs_remaining--;
+ drvdata->state = GXP_I2C_COMP;
+ gxp_i2c_stop(drvdata);
+ return;
+ }
+ drvdata->state = GXP_I2C_RDATA_PHASE;
+
+ if (drvdata->buf_remaining == 1) {
+ /* The last data, do not ack */
+ writeb(MASTER_EVT_CLR | RW_CMD,
+ drvdata->base + GXP_I2CMCMD);
+ } else {
+ /* Read data and ack it */
+ writeb(MASTER_EVT_CLR | MASTER_ACK_ENAB |
+ RW_CMD, drvdata->base + GXP_I2CMCMD);
+ }
+ } else {
+ /* Start to write first data to slave */
+ if (drvdata->buf_remaining == 0) {
+ /* No more data to write, stop */
+ drvdata->msgs_remaining--;
+ drvdata->state = GXP_I2C_COMP;
+ gxp_i2c_stop(drvdata);
+ return;
+ }
+ value = *drvdata->buf;
+ value = value << 8;
+ /* Clear master event */
+ value |= MASTER_EVT_CLR;
+ drvdata->buf++;
+ drvdata->buf_remaining--;
+ drvdata->state = GXP_I2C_WDATA_PHASE;
+ writew(value, drvdata->base + GXP_I2CMCMD);
+ }
+}
+
+static void gxp_i2c_ack_data(struct gxp_i2c_drvdata *drvdata)
+{
+ u8 value;
+
+ /* Store the data returned */
+ value = readb(drvdata->base + GXP_I2CSNPDAT);
+ *drvdata->buf = value;
+ drvdata->buf++;
+ drvdata->buf_remaining--;
+
+ if (drvdata->buf_remaining == 0) {
+ /* No more data, this message is completed. */
+ drvdata->msgs_remaining--;
+
+ if (drvdata->msgs_remaining == 0) {
+ /* No more messages, stop */
+ drvdata->state = GXP_I2C_COMP;
+ gxp_i2c_stop(drvdata);
+ return;
+ }
+ /* Move to next message and start transfer */
+ drvdata->curr_msg++;
+ gxp_i2c_restart(drvdata);
+ return;
+ }
+
+ /* Ack the slave to make it send next byte */
+ drvdata->state = GXP_I2C_RDATA_PHASE;
+ if (drvdata->buf_remaining == 1) {
+ /* The last data, do not ack */
+ writeb(MASTER_EVT_CLR | RW_CMD,
+ drvdata->base + GXP_I2CMCMD);
+ } else {
+ /* Read data and ack it */
+ writeb(MASTER_EVT_CLR | MASTER_ACK_ENAB |
+ RW_CMD, drvdata->base + GXP_I2CMCMD);
+ }
+}
+
+static void gxp_i2c_chk_data_ack(struct gxp_i2c_drvdata *drvdata)
+{
+ u16 value;
+
+ value = readb(drvdata->base + GXP_I2CSTAT);
+ if (!(value & MASK_ACK)) {
+ /* Received No ack, stop */
+ drvdata->state = GXP_I2C_DATA_NACK;
+ gxp_i2c_stop(drvdata);
+ return;
+ }
+
+ /* Got ack, check if there is more data to write */
+ if (drvdata->buf_remaining == 0) {
+ /* No more data, this message is completed */
+ drvdata->msgs_remaining--;
+
+ if (drvdata->msgs_remaining == 0) {
+ /* No more messages, stop */
+ drvdata->state = GXP_I2C_COMP;
+ gxp_i2c_stop(drvdata);
+ return;
+ }
+ /* Move to next message and start transfer */
+ drvdata->curr_msg++;
+ gxp_i2c_restart(drvdata);
+ return;
+ }
+
+ /* Write data to slave */
+ value = *drvdata->buf;
+ value = value << 8;
+
+ /* Clear master event */
+ value |= MASTER_EVT_CLR;
+ drvdata->buf++;
+ drvdata->buf_remaining--;
+ drvdata->state = GXP_I2C_WDATA_PHASE;
+ writew(value, drvdata->base + GXP_I2CMCMD);
+}
+
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+static bool gxp_i2c_slave_irq_handler(struct gxp_i2c_drvdata *drvdata)
+{
+ u8 value;
+ u8 buf;
+ int ret;
+
+ value = readb(drvdata->base + GXP_I2CEVTERR);
+
+ /* Received start or stop event */
+ if (value & MASK_SLAVE_CMD_EVENT) {
+ value = readb(drvdata->base + GXP_I2CSTAT);
+ /* Master sent stop */
+ if (value & MASK_STOP_EVENT) {
+ if (drvdata->stopped == 0)
+ i2c_slave_event(drvdata->slave, I2C_SLAVE_STOP, &buf);
+ writeb(SLAVE_EVT_CLR | SNOOP_EVT_MASK |
+ SLAVE_ACK_ENAB | SLAVE_EVT_STALL, drvdata->base + GXP_I2CSCMD);
+ drvdata->stopped = 1;
+ } else {
+ /* Master sent start and wants to read */
+ drvdata->stopped = 0;
+ if (value & MASK_RW) {
+ i2c_slave_event(drvdata->slave,
+ I2C_SLAVE_READ_REQUESTED, &buf);
+ value = buf << 8 | (SLAVE_EVT_CLR | SNOOP_EVT_MASK |
+ SLAVE_EVT_STALL);
+ writew(value, drvdata->base + GXP_I2CSCMD);
+ } else {
+ /* Master wants to write to us */
+ ret = i2c_slave_event(drvdata->slave,
+ I2C_SLAVE_WRITE_REQUESTED, &buf);
+ if (!ret) {
+ /* Ack next byte from master */
+ writeb(SLAVE_EVT_CLR | SNOOP_EVT_MASK |
+ SLAVE_ACK_ENAB | SLAVE_EVT_STALL,
+ drvdata->base + GXP_I2CSCMD);
+ } else {
+ /* Nack next byte from master */
+ writeb(SLAVE_EVT_CLR | SNOOP_EVT_MASK |
+ SLAVE_EVT_STALL, drvdata->base + GXP_I2CSCMD);
+ }
+ }
+ }
+ } else if (value & MASK_SLAVE_DATA_EVENT) {
+ value = readb(drvdata->base + GXP_I2CSTAT);
+ /* Master wants to read */
+ if (value & MASK_RW) {
+ /* Master wants another byte */
+ if (value & MASK_ACK) {
+ i2c_slave_event(drvdata->slave,
+ I2C_SLAVE_READ_PROCESSED, &buf);
+ value = buf << 8 | (SLAVE_EVT_CLR | SNOOP_EVT_MASK |
+ SLAVE_EVT_STALL);
+ writew(value, drvdata->base + GXP_I2CSCMD);
+ } else {
+ /* No more bytes needed */
+ writew(SLAVE_EVT_CLR | SNOOP_EVT_MASK |
+ SLAVE_ACK_ENAB | SLAVE_EVT_STALL,
+ drvdata->base + GXP_I2CSCMD);
+ }
+ } else {
+ /* Master wants to write to us */
+ value = readb(drvdata->base + GXP_I2CSNPDAT);
+ buf = (uint8_t)value;
+ ret = i2c_slave_event(drvdata->slave,
+ I2C_SLAVE_WRITE_RECEIVED, &buf);
+ if (!ret) {
+ /* Ack next byte from master */
+ writeb(SLAVE_EVT_CLR | SNOOP_EVT_MASK |
+ SLAVE_ACK_ENAB | SLAVE_EVT_STALL,
+ drvdata->base + GXP_I2CSCMD);
+ } else {
+ /* Nack next byte from master */
+ writeb(SLAVE_EVT_CLR | SNOOP_EVT_MASK |
+ SLAVE_EVT_STALL, drvdata->base + GXP_I2CSCMD);
+ }
+ }
+ } else {
+ return false;
+ }
+
+ return true;
+}
+#endif
+
+static irqreturn_t gxp_i2c_irq_handler(int irq, void *_drvdata)
+{
+ struct gxp_i2c_drvdata *drvdata = (struct gxp_i2c_drvdata *)_drvdata;
+ u32 value;
+
+ /* Check if the interrupt is for the current engine */
+ regmap_read(i2cg_map, GXP_I2CINTSTAT, &value);
+ if (!(value & BIT(drvdata->engine)))
+ return IRQ_NONE;
+
+ value = readb(drvdata->base + GXP_I2CEVTERR);
+
+ /* Error */
+ if (value & ~(MASK_MASTER_EVENT | MASK_SLAVE_CMD_EVENT |
+ MASK_SLAVE_DATA_EVENT)) {
+ /* Clear all events */
+ writeb(0x00, drvdata->base + GXP_I2CEVTERR);
+ drvdata->state = GXP_I2C_ERROR;
+ gxp_i2c_stop(drvdata);
+ return IRQ_HANDLED;
+ }
+
+ if (IS_ENABLED(CONFIG_I2C_SLAVE)) {
+ /* Slave mode */
+ if (value & (MASK_SLAVE_CMD_EVENT | MASK_SLAVE_DATA_EVENT)) {
+ if (gxp_i2c_slave_irq_handler(drvdata))
+ return IRQ_HANDLED;
+ return IRQ_NONE;
+ }
+ }
+
+ /* Master mode */
+ switch (drvdata->state) {
+ case GXP_I2C_ADDR_PHASE:
+ gxp_i2c_chk_addr_ack(drvdata);
+ break;
+
+ case GXP_I2C_RDATA_PHASE:
+ gxp_i2c_ack_data(drvdata);
+ break;
+
+ case GXP_I2C_WDATA_PHASE:
+ gxp_i2c_chk_data_ack(drvdata);
+ break;
+ }
+
+ return IRQ_HANDLED;
+}
+
+static void gxp_i2c_init(struct gxp_i2c_drvdata *drvdata)
+{
+ drvdata->state = GXP_I2C_IDLE;
+ writeb(2000000 / drvdata->t.bus_freq_hz,
+ drvdata->base + GXP_I2CFREQDIV);
+ writeb(FILTER_CNT | FAIRNESS_CNT,
+ drvdata->base + GXP_I2CFLTFAIR);
+ writeb(GXP_DATA_EDGE_RST_CTRL, drvdata->base + GXP_I2CTMOEDG);
+ writeb(0x00, drvdata->base + GXP_I2CCYCTIM);
+ writeb(0x00, drvdata->base + GXP_I2CSNPAA);
+ writeb(0x00, drvdata->base + GXP_I2CADVFEAT);
+ writeb(SNOOP_EVT_CLR | SLAVE_EVT_CLR | SNOOP_EVT_MASK |
+ SLAVE_EVT_MASK, drvdata->base + GXP_I2CSCMD);
+ writeb(MASTER_EVT_CLR, drvdata->base + GXP_I2CMCMD);
+ writeb(0x00, drvdata->base + GXP_I2CEVTERR);
+ writeb(0x00, drvdata->base + GXP_I2COWNADR);
+}
+
+static int gxp_i2c_probe(struct platform_device *pdev)
+{
+ struct gxp_i2c_drvdata *drvdata;
+ int rc;
+ struct i2c_adapter *adapter;
+
+ if (!i2cg_map) {
+ i2cg_map = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
+ "hpe,sysreg");
+ if (IS_ERR(i2cg_map)) {
+ return dev_err_probe(&pdev->dev, IS_ERR(i2cg_map),
+ "failed to map i2cg_handle\n");
+ }
+
+ /* Disable interrupt */
+ regmap_update_bits(i2cg_map, GXP_I2CINTEN, 0x00000FFF, 0);
+ }
+
+ drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata),
+ GFP_KERNEL);
+ if (!drvdata)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, drvdata);
+ drvdata->dev = &pdev->dev;
+ init_completion(&drvdata->completion);
+
+ drvdata->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(drvdata->base))
+ return PTR_ERR(drvdata->base);
+
+ /* Use physical memory address to determine which I2C engine this is. */
+ drvdata->engine = ((size_t)drvdata->base & 0xf00) >> 8;
+
+ if (drvdata->engine >= GXP_MAX_I2C_ENGINE) {
+ return dev_err_probe(&pdev->dev, -EINVAL, "i2c engine% is unsupported\n",
+ drvdata->engine);
+ }
+
+ rc = platform_get_irq(pdev, 0);
+ if (rc < 0)
+ return rc;
+
+ drvdata->irq = rc;
+ rc = devm_request_irq(&pdev->dev, drvdata->irq, gxp_i2c_irq_handler,
+ IRQF_SHARED, gxp_i2c_name[drvdata->engine], drvdata);
+ if (rc < 0)
+ return dev_err_probe(&pdev->dev, rc, "irq request failed\n");
+
+ i2c_parse_fw_timings(&pdev->dev, &drvdata->t, true);
+
+ gxp_i2c_init(drvdata);
+
+ /* Enable interrupt */
+ regmap_update_bits(i2cg_map, GXP_I2CINTEN, BIT(drvdata->engine),
+ BIT(drvdata->engine));
+
+ adapter = &drvdata->adapter;
+ i2c_set_adapdata(adapter, drvdata);
+
+ adapter->owner = THIS_MODULE;
+ strscpy(adapter->name, "HPE GXP I2C adapter", sizeof(adapter->name));
+ adapter->algo = &gxp_i2c_algo;
+ adapter->dev.parent = &pdev->dev;
+ adapter->dev.of_node = pdev->dev.of_node;
+
+ rc = i2c_add_adapter(adapter);
+ if (rc)
+ return dev_err_probe(&pdev->dev, rc, "i2c add adapter failed\n");
+
+ return 0;
+}
+
+static int gxp_i2c_remove(struct platform_device *pdev)
+{
+ struct gxp_i2c_drvdata *drvdata = platform_get_drvdata(pdev);
+
+ /* Disable interrupt */
+ regmap_update_bits(i2cg_map, GXP_I2CINTEN, BIT(drvdata->engine), 0);
+ i2c_del_adapter(&drvdata->adapter);
+
+ return 0;
+}
+
+static const struct of_device_id gxp_i2c_of_match[] = {
+ { .compatible = "hpe,gxp-i2c" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, gxp_i2c_of_match);
+
+static struct platform_driver gxp_i2c_driver = {
+ .probe = gxp_i2c_probe,
+ .remove = gxp_i2c_remove,
+ .driver = {
+ .name = "gxp-i2c",
+ .of_match_table = gxp_i2c_of_match,
+ },
+};
+module_platform_driver(gxp_i2c_driver);
+
+MODULE_AUTHOR("Nick Hawkins <nick.hawkins@hpe.com>");
+MODULE_DESCRIPTION("HPE GXP I2C bus driver");
+MODULE_LICENSE("GPL");
projects / platform / kernel / linux-rpi.git / commitdiff