[PATCH v3 2/3] i2c: designware: Support per-variant reg/bit offsets and intr handling

[Aniket Limaye <a-limaye@ti.com>]

Every DW_IC_* register offset and CON-register bit position is currently
baked in as a compile-time constant, which only works while there is a
single register layout.

- Make DW_IC_* a logical enum (enum dw_ic_reg_id) and the regmap
  internally translates to physical offsets.
- Add a struct to hold the CON-register bitfield positions.
- Fold the read-to-clear interrupt-acknowledgment pattern into a new
  i2c_dw_ack_intr() helper, driven by a per-variant dev->intr_clr[].

All of these are selected at probe time via the new
i2c_dw_select_variant().

Only one variant exists at this point (DW_apb_i2c), so this is a
mechanical, behavior-preserving change. It lays the groundwork for
adding a second register layout without duplicating the whole driver.

Signed-off-by: Aniket Limaye <a-limaye@ti.com>

---

Changes in v3:
- Revert to special handling for the max_register in regmap for
  MODEL_AMD_NAVI_GPU instead of unconditionally including
  AMD_UCSI_INTR_REG in the legal regmap range.
- Link to v2: https://lore.kernel.org/all/20260925-tda54-upstream-i2c-v2-2-261785e58493@ti.com/

Changes in v2:
- Move the Reg ID -> Offset mapping inside the regmap functions such
  that existing calls to reg_read/write are unaltered. This does change
  the reg_read()/reg_write() functions to take reg IDs as input rather
  than their physical offsets, which also requires updates to the
  xe_i2c.c driver to handle the same mapping.
- Link to v1: https://lore.kernel.org/r/20260919-tda54-upstream-i2c-v1-2-b0b9f77be18b@ti.com/
---
 drivers/gpu/drm/xe/regs/xe_i2c_regs.h       |   3 +-
 drivers/i2c/busses/i2c-designware-amdisp.c  |   1 +
 drivers/i2c/busses/i2c-designware-common.c  |  71 +++++++++++---
 drivers/i2c/busses/i2c-designware-core.h    |  52 ++++++++++-
 drivers/i2c/busses/i2c-designware-master.c  |  54 +++++------
 drivers/i2c/busses/i2c-designware-pcidrv.c  |   2 +
 drivers/i2c/busses/i2c-designware-platdrv.c |   2 +
 drivers/i2c/busses/i2c-designware-slave.c   |  26 +++---
 include/linux/designware_i2c.h              | 137 +++++++++++++++++++---------
 9 files changed, 252 insertions(+), 96 deletions(-)

diff --git a/drivers/gpu/drm/xe/regs/xe_i2c_regs.h b/drivers/gpu/drm/xe/regs/xe_i2c_regs.h
index 37550e4a20f8..86449efb4a98 100644
--- a/drivers/gpu/drm/xe/regs/xe_i2c_regs.h
+++ b/drivers/gpu/drm/xe/regs/xe_i2c_regs.h
@@ -2,6 +2,7 @@
 #ifndef _XE_I2C_REGS_H_
 #define _XE_I2C_REGS_H_
 
+#include <linux/designware_i2c.h>
 #include <linux/pci_regs.h>
 
 #include "xe_reg_defs.h"
@@ -20,6 +21,6 @@
 #define I2C_CONFIG_CMD			XE_REG(I2C_CONFIG_SPACE_OFFSET + PCI_COMMAND)
 #define I2C_CONFIG_PMCSR		XE_REG(I2C_CONFIG_SPACE_OFFSET + 0x84)
 
-#define I2C_REG(reg)			XE_REG((reg) + I2C_MEM_SPACE_OFFSET)
+#define I2C_REG(reg)			XE_REG(dw_i2c_reg_offsets[reg] + I2C_MEM_SPACE_OFFSET)
 
 #endif /* _XE_I2C_REGS_H_ */
diff --git a/drivers/i2c/busses/i2c-designware-amdisp.c b/drivers/i2c/busses/i2c-designware-amdisp.c
index 9f0ec0fae6f2..f7aa075c9977 100644
--- a/drivers/i2c/busses/i2c-designware-amdisp.c
+++ b/drivers/i2c/busses/i2c-designware-amdisp.c
@@ -46,6 +46,7 @@ static int amd_isp_dw_i2c_plat_probe(struct platform_device *pdev)
 	isp_i2c_dev->flags |= ACCESS_POLLING;
 	platform_set_drvdata(pdev, isp_i2c_dev);
 
+	i2c_dw_select_variant(isp_i2c_dev);
 	isp_i2c_dev->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(isp_i2c_dev->base))
 		return dev_err_probe(&pdev->dev, PTR_ERR(isp_i2c_dev->base),
diff --git a/drivers/i2c/busses/i2c-designware-common.c b/drivers/i2c/busses/i2c-designware-common.c
index a1eca6cd4b75..bd25b9c582c1 100644
--- a/drivers/i2c/busses/i2c-designware-common.c
+++ b/drivers/i2c/busses/i2c-designware-common.c
@@ -72,11 +72,55 @@ static const char *const abort_sources[] = {
 		"incorrect slave-transmitter mode configuration",
 };
 
+static const struct dw_i2c_con_bits dw_i2c_con_bits = {
+	.master			= DW_IC_CON_MASTER,
+	.speed_std		= DW_IC_CON_SPEED_STD,
+	.speed_fast		= DW_IC_CON_SPEED_FAST,
+	.speed_high		= DW_IC_CON_SPEED_HIGH,
+	.speed_mask		= DW_IC_CON_SPEED_MASK,
+	.bit10_slave		= DW_IC_CON_10BITADDR_SLAVE,
+	.bit10_master		= DW_IC_CON_10BITADDR_MASTER,
+	.restart_en		= DW_IC_CON_RESTART_EN,
+	.slave_disable		= DW_IC_CON_SLAVE_DISABLE,
+	.stop_det_ifaddressed	= DW_IC_CON_STOP_DET_IFADDRESSED,
+	.tx_empty_ctrl		= DW_IC_CON_TX_EMPTY_CTRL,
+	.rx_fifo_full_hld_ctrl	= DW_IC_CON_RX_FIFO_FULL_HLD_CTRL,
+	.bus_clear_ctrl		= DW_IC_CON_BUS_CLEAR_CTRL,
+};
+
+/* "snps,designware-i2c": dedicated read-to-clear register ID per logical interrupt */
+static const u32 dw_i2c_intr_clr[DW_INTR_IDX_MAX] = {
+	[DW_INTR_IDX_INTR]      = DW_IC_CLR_INTR,
+	[DW_INTR_IDX_RX_UNDER]  = DW_IC_CLR_RX_UNDER,
+	[DW_INTR_IDX_RX_OVER]   = DW_IC_CLR_RX_OVER,
+	[DW_INTR_IDX_TX_OVER]   = DW_IC_CLR_TX_OVER,
+	[DW_INTR_IDX_RD_REQ]    = DW_IC_CLR_RD_REQ,
+	[DW_INTR_IDX_TX_ABRT]   = DW_IC_CLR_TX_ABRT,
+	[DW_INTR_IDX_RX_DONE]   = DW_IC_CLR_RX_DONE,
+	[DW_INTR_IDX_ACTIVITY]  = DW_IC_CLR_ACTIVITY,
+	[DW_INTR_IDX_STOP_DET]  = DW_IC_CLR_STOP_DET,
+	[DW_INTR_IDX_START_DET] = DW_IC_CLR_START_DET,
+	[DW_INTR_IDX_GEN_CALL]  = DW_IC_CLR_GEN_CALL,
+};
+
+/**
+ * i2c_dw_select_variant() - Pick the register offset table, CON-register bit
+ * layout and interrupt-ack mapping matching this device's IP variant
+ * @dev: device private data
+ */
+void i2c_dw_select_variant(struct dw_i2c_dev *dev)
+{
+	dev->regs = dw_i2c_reg_offsets;
+	dev->con_bits = &dw_i2c_con_bits;
+	dev->intr_clr = dw_i2c_intr_clr;
+}
+EXPORT_SYMBOL_GPL(i2c_dw_select_variant);
+
 static int dw_reg_read(void *context, unsigned int reg, unsigned int *val)
 {
 	struct dw_i2c_dev *dev = context;
 
-	*val = readl(dev->base + reg);
+	*val = readl(dev->base + dev->regs[reg]);
 
 	return 0;
 }
@@ -85,7 +129,7 @@ static int dw_reg_write(void *context, unsigned int reg, unsigned int val)
 {
 	struct dw_i2c_dev *dev = context;
 
-	writel(val, dev->base + reg);
+	writel(val, dev->base + dev->regs[reg]);
 
 	return 0;
 }
@@ -94,7 +138,7 @@ static int dw_reg_read_swab(void *context, unsigned int reg, unsigned int *val)
 {
 	struct dw_i2c_dev *dev = context;
 
-	*val = swab32(readl(dev->base + reg));
+	*val = swab32(readl(dev->base + dev->regs[reg]));
 
 	return 0;
 }
@@ -103,7 +147,7 @@ static int dw_reg_write_swab(void *context, unsigned int reg, unsigned int val)
 {
 	struct dw_i2c_dev *dev = context;
 
-	writel(swab32(val), dev->base + reg);
+	writel(swab32(val), dev->base + dev->regs[reg]);
 
 	return 0;
 }
@@ -111,9 +155,10 @@ static int dw_reg_write_swab(void *context, unsigned int reg, unsigned int val)
 static int dw_reg_read_word(void *context, unsigned int reg, unsigned int *val)
 {
 	struct dw_i2c_dev *dev = context;
+	unsigned int offset = dev->regs[reg];
 
-	*val = readw(dev->base + reg) |
-		(readw(dev->base + reg + DW_IC_REG_STEP_BYTES) << DW_IC_REG_WORD_SHIFT);
+	*val = readw(dev->base + offset) |
+		(readw(dev->base + offset + DW_IC_REG_STEP_BYTES) << DW_IC_REG_WORD_SHIFT);
 
 	return 0;
 }
@@ -121,9 +166,10 @@ static int dw_reg_read_word(void *context, unsigned int reg, unsigned int *val)
 static int dw_reg_write_word(void *context, unsigned int reg, unsigned int val)
 {
 	struct dw_i2c_dev *dev = context;
+	unsigned int offset = dev->regs[reg];
 
-	writew(val, dev->base + reg);
-	writew(val >> DW_IC_REG_WORD_SHIFT, dev->base + reg + DW_IC_REG_STEP_BYTES);
+	writew(val, dev->base + offset);
+	writew(val >> DW_IC_REG_WORD_SHIFT, dev->base + offset + DW_IC_REG_STEP_BYTES);
 
 	return 0;
 }
@@ -143,7 +189,7 @@ static int i2c_dw_init_regmap(struct dw_i2c_dev *dev)
 	struct regmap_config map_cfg = {
 		.reg_bits = 32,
 		.val_bits = 32,
-		.reg_stride = 4,
+		.reg_stride = 1,
 		.disable_locking = true,
 		.reg_read = dw_reg_read,
 		.reg_write = dw_reg_write,
@@ -163,7 +209,7 @@ static int i2c_dw_init_regmap(struct dw_i2c_dev *dev)
 	if (ret)
 		return ret;
 
-	reg = readl(dev->base + DW_IC_COMP_TYPE);
+	reg = readl(dev->base + dev->regs[DW_IC_COMP_TYPE]);
 	i2c_dw_release_lock(dev);
 
 	if ((dev->flags & MODEL_MASK) == MODEL_AMD_NAVI_GPU)
@@ -845,7 +891,6 @@ u32 i2c_dw_func(struct i2c_adapter *adap)
 
 void i2c_dw_disable(struct dw_i2c_dev *dev)
 {
-	unsigned int dummy;
 	int ret;
 
 	ret = i2c_dw_acquire_lock(dev);
@@ -857,7 +902,7 @@ void i2c_dw_disable(struct dw_i2c_dev *dev)
 
 	/* Disable all interrupts */
 	__i2c_dw_write_intr_mask(dev, 0);
-	regmap_read(dev->map, DW_IC_CLR_INTR, &dummy);
+	i2c_dw_ack_intr(dev, DW_INTR_IDX_INTR);
 
 	i2c_dw_release_lock(dev);
 }
@@ -1055,7 +1100,7 @@ void i2c_dw_shutdown(struct dw_i2c_dev *dev)
 	 * disable bit while the controller is still enabled.
 	 */
 	regmap_read(dev->map, DW_IC_CON, &con);
-	con |= DW_IC_CON_SLAVE_DISABLE;
+	con |= dev->con_bits->slave_disable;
 	regmap_write(dev->map, DW_IC_CON, con);
 
 	i2c_dw_disable(dev);
diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
index 2c929a6e8da2..4c782594ab4e 100644
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -43,6 +43,42 @@
 #define DW_IC_SDA_HOLD_MIN_VERS			0x3131312A /* "111*" == v1.11* */
 #define DW_IC_COMP_TYPE_VALUE			0x44570140 /* "DW" + 0x0140 */
 
+/*
+ * Bit positions within the CON register that could differ between IP
+ * variants.
+ */
+struct dw_i2c_con_bits {
+	u32 master;
+	u32 speed_std;
+	u32 speed_fast;
+	u32 speed_high;
+	u32 speed_mask;
+	u32 bit10_slave;
+	u32 bit10_master;
+	u32 restart_en;
+	u32 slave_disable;
+	u32 stop_det_ifaddressed;
+	u32 tx_empty_ctrl;
+	u32 rx_fifo_full_hld_ctrl;
+	u32 bus_clear_ctrl;
+};
+
+/* Logical interrupt IDs for i2c_dw_ack_intr() */
+enum dw_i2c_intr_idx {
+	DW_INTR_IDX_INTR,
+	DW_INTR_IDX_RX_UNDER,
+	DW_INTR_IDX_RX_OVER,
+	DW_INTR_IDX_TX_OVER,
+	DW_INTR_IDX_RD_REQ,
+	DW_INTR_IDX_TX_ABRT,
+	DW_INTR_IDX_RX_DONE,
+	DW_INTR_IDX_ACTIVITY,
+	DW_INTR_IDX_STOP_DET,
+	DW_INTR_IDX_START_DET,
+	DW_INTR_IDX_GEN_CALL,
+	DW_INTR_IDX_MAX,
+};
+
 #define DW_IC_INTR_DEFAULT_MASK			(DW_IC_INTR_RX_FULL | \
 						 DW_IC_INTR_TX_ABRT | \
 						 DW_IC_INTR_STOP_DET)
@@ -126,6 +162,9 @@ struct reset_control;
  * struct dw_i2c_dev - private i2c-designware data
  * @dev: driver model device node
  * @map: IO registers map
+ * @regs: logical-to-physical register offset table for the active IP variant
+ * @con_bits: CON register bit-layout for the active IP variant
+ * @intr_clr: logical intr number to reg table for the active IP variant
  * @sysmap: System controller registers map
  * @base: IO registers pointer
  * @ext: Extended IO registers pointer
@@ -189,6 +228,9 @@ struct reset_control;
 struct dw_i2c_dev {
 	struct device		*dev;
 	struct regmap		*map;
+	const u32		*regs;
+	const struct dw_i2c_con_bits *con_bits;
+	const u32		*intr_clr;
 	struct regmap		*sysmap;
 	void __iomem		*base;
 	void __iomem		*ext;
@@ -255,7 +297,6 @@ struct dw_i2c_dev {
  * Enable UCSI interrupt by writing 0xd at register
  * offset 0x474 specified in hardware specification.
  */
-#define AMD_UCSI_INTR_REG			0x474
 #define AMD_UCSI_INTR_EN			0xd
 
 #define TXGBE_TX_FIFO_DEPTH			4
@@ -265,6 +306,7 @@ struct i2c_dw_semaphore_callbacks {
 	int	(*probe)(struct dw_i2c_dev *dev);
 };
 
+void i2c_dw_select_variant(struct dw_i2c_dev *dev);
 u32 i2c_dw_scl_hcnt(struct dw_i2c_dev *dev, unsigned int reg, u32 ic_clk,
 		    u32 tSYMBOL, u32 tf, int offset);
 u32 i2c_dw_scl_lcnt(struct dw_i2c_dev *dev, unsigned int reg, u32 ic_clk,
@@ -310,6 +352,14 @@ static inline void __i2c_dw_read_intr_mask(struct dw_i2c_dev *dev,
 		*intr_mask = dev->sw_mask;
 }
 
+/* Acknowledge a logical interrupt via dev->intr_clr[]: reg ID */
+static inline void i2c_dw_ack_intr(struct dw_i2c_dev *dev, enum dw_i2c_intr_idx intr)
+{
+	unsigned int dummy;
+
+	regmap_read(dev->map, dev->intr_clr[intr], &dummy);
+}
+
 void __i2c_dw_disable(struct dw_i2c_dev *dev);
 void i2c_dw_disable(struct dw_i2c_dev *dev);
 
diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c
index a1bcc3797e4f..329f958ded3e 100644
--- a/drivers/i2c/busses/i2c-designware-master.c
+++ b/drivers/i2c/busses/i2c-designware-master.c
@@ -133,14 +133,14 @@ static int i2c_dw_set_timings_master(struct dw_i2c_dev *dev)
 		fp_str, dev->fs_hcnt, dev->fs_lcnt);
 
 	/* Check is high speed possible and fall back to fast mode if not */
-	if ((dev->master_cfg & DW_IC_CON_SPEED_MASK) ==
-		DW_IC_CON_SPEED_HIGH) {
+	if ((dev->master_cfg & dev->con_bits->speed_mask) ==
+		dev->con_bits->speed_high) {
 		if ((comp_param1 & DW_IC_COMP_PARAM_1_SPEED_MODE_MASK)
 			!= DW_IC_COMP_PARAM_1_SPEED_MODE_HIGH) {
 			dev_err(dev->dev, "High Speed not supported!\n");
 			t->bus_freq_hz = I2C_MAX_FAST_MODE_FREQ;
-			dev->master_cfg &= ~DW_IC_CON_SPEED_MASK;
-			dev->master_cfg |= DW_IC_CON_SPEED_FAST;
+			dev->master_cfg &= ~dev->con_bits->speed_mask;
+			dev->master_cfg |= dev->con_bits->speed_fast;
 			dev->hs_hcnt = 0;
 			dev->hs_lcnt = 0;
 		} else if (!dev->hs_hcnt || !dev->hs_lcnt) {
@@ -200,7 +200,7 @@ static void i2c_dw_xfer_init(struct dw_i2c_dev *dev)
 
 	/* If the slave address is ten bit address, enable 10BITADDR */
 	if (msgs[dev->msg_write_idx].flags & I2C_M_TEN) {
-		ic_con = DW_IC_CON_10BITADDR_MASTER;
+		ic_con = dev->con_bits->bit10_master;
 		/*
 		 * If I2C_DYNAMIC_TAR_UPDATE is set, the 10-bit addressing
 		 * mode has to be enabled via bit 12 of IC_TAR register.
@@ -210,7 +210,7 @@ static void i2c_dw_xfer_init(struct dw_i2c_dev *dev)
 		ic_tar = DW_IC_TAR_10BITADDR_MASTER;
 	}
 
-	regmap_update_bits(dev->map, DW_IC_CON, DW_IC_CON_10BITADDR_MASTER,
+	regmap_update_bits(dev->map, DW_IC_CON, dev->con_bits->bit10_master,
 			   ic_con);
 
 	/*
@@ -230,7 +230,7 @@ static void i2c_dw_xfer_init(struct dw_i2c_dev *dev)
 	regmap_read(dev->map, DW_IC_ENABLE_STATUS, &dummy);
 
 	/* Clear and enable interrupts */
-	regmap_read(dev->map, DW_IC_CLR_INTR, &dummy);
+	i2c_dw_ack_intr(dev, DW_INTR_IDX_INTR);
 	__i2c_dw_write_intr_mask(dev, DW_IC_INTR_MASTER_MASK);
 }
 
@@ -399,8 +399,8 @@ i2c_dw_xfer_msg(struct dw_i2c_dev *dev)
 			 * IC_RESTART_EN are set, we must manually
 			 * set restart bit between messages.
 			 */
-			if ((dev->master_cfg & DW_IC_CON_RESTART_EN) &&
-					(dev->msg_write_idx > 0))
+			if (dev->master_cfg & dev->con_bits->restart_en &&
+			    dev->msg_write_idx > 0)
 				need_restart = true;
 		}
 
@@ -574,7 +574,7 @@ i2c_dw_read(struct dw_i2c_dev *dev)
 
 static u32 i2c_dw_read_clear_intrbits(struct dw_i2c_dev *dev)
 {
-	unsigned int stat, dummy;
+	unsigned int stat;
 
 	/*
 	 * The IC_INTR_STAT register just indicates "enabled" interrupts.
@@ -603,32 +603,32 @@ static u32 i2c_dw_read_clear_intrbits(struct dw_i2c_dev *dev)
 	 * Instead, use the separately-prepared IC_CLR_* registers.
 	 */
 	if (stat & DW_IC_INTR_RX_UNDER)
-		regmap_read(dev->map, DW_IC_CLR_RX_UNDER, &dummy);
+		i2c_dw_ack_intr(dev, DW_INTR_IDX_RX_UNDER);
 	if (stat & DW_IC_INTR_RX_OVER)
-		regmap_read(dev->map, DW_IC_CLR_RX_OVER, &dummy);
+		i2c_dw_ack_intr(dev, DW_INTR_IDX_RX_OVER);
 	if (stat & DW_IC_INTR_TX_OVER)
-		regmap_read(dev->map, DW_IC_CLR_TX_OVER, &dummy);
+		i2c_dw_ack_intr(dev, DW_INTR_IDX_TX_OVER);
 	if (stat & DW_IC_INTR_RD_REQ)
-		regmap_read(dev->map, DW_IC_CLR_RD_REQ, &dummy);
+		i2c_dw_ack_intr(dev, DW_INTR_IDX_RD_REQ);
 	if (stat & DW_IC_INTR_TX_ABRT) {
 		/*
 		 * The IC_TX_ABRT_SOURCE register is cleared whenever
 		 * the IC_CLR_TX_ABRT is read.  Preserve it beforehand.
 		 */
 		regmap_read(dev->map, DW_IC_TX_ABRT_SOURCE, &dev->abort_source);
-		regmap_read(dev->map, DW_IC_CLR_TX_ABRT, &dummy);
+		i2c_dw_ack_intr(dev, DW_INTR_IDX_TX_ABRT);
 	}
 	if (stat & DW_IC_INTR_RX_DONE)
-		regmap_read(dev->map, DW_IC_CLR_RX_DONE, &dummy);
+		i2c_dw_ack_intr(dev, DW_INTR_IDX_RX_DONE);
 	if (stat & DW_IC_INTR_ACTIVITY)
-		regmap_read(dev->map, DW_IC_CLR_ACTIVITY, &dummy);
+		i2c_dw_ack_intr(dev, DW_INTR_IDX_ACTIVITY);
 	if ((stat & DW_IC_INTR_STOP_DET) &&
 	    ((dev->rx_outstanding == 0) || (stat & DW_IC_INTR_RX_FULL)))
-		regmap_read(dev->map, DW_IC_CLR_STOP_DET, &dummy);
+		i2c_dw_ack_intr(dev, DW_INTR_IDX_STOP_DET);
 	if (stat & DW_IC_INTR_START_DET)
-		regmap_read(dev->map, DW_IC_CLR_START_DET, &dummy);
+		i2c_dw_ack_intr(dev, DW_INTR_IDX_START_DET);
 	if (stat & DW_IC_INTR_GEN_CALL)
-		regmap_read(dev->map, DW_IC_CLR_GEN_CALL, &dummy);
+		i2c_dw_ack_intr(dev, DW_INTR_IDX_GEN_CALL);
 
 	return stat;
 }
@@ -940,20 +940,20 @@ void i2c_dw_configure_master(struct dw_i2c_dev *dev)
 	if ((dev->flags & MODEL_MASK) != MODEL_AMD_NAVI_GPU)
 		dev->functionality |= I2C_FUNC_PROTOCOL_MANGLING;
 
-	dev->master_cfg = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE |
-			  DW_IC_CON_RESTART_EN;
+	dev->master_cfg = dev->con_bits->master | dev->con_bits->slave_disable |
+			  dev->con_bits->restart_en;
 
 	dev->mode = DW_IC_MASTER;
 
 	switch (t->bus_freq_hz) {
 	case I2C_MAX_STANDARD_MODE_FREQ:
-		dev->master_cfg |= DW_IC_CON_SPEED_STD;
+		dev->master_cfg |= dev->con_bits->speed_std;
 		break;
 	case I2C_MAX_HIGH_SPEED_MODE_FREQ:
-		dev->master_cfg |= DW_IC_CON_SPEED_HIGH;
+		dev->master_cfg |= dev->con_bits->speed_high;
 		break;
 	default:
-		dev->master_cfg |= DW_IC_CON_SPEED_FAST;
+		dev->master_cfg |= dev->con_bits->speed_fast;
 	}
 }
 EXPORT_SYMBOL_GPL(i2c_dw_configure_master);
@@ -1042,8 +1042,8 @@ int i2c_dw_probe_master(struct dw_i2c_dev *dev)
 	if (ret)
 		return ret;
 
-	if (ic_con & DW_IC_CON_BUS_CLEAR_CTRL)
-		dev->master_cfg |= DW_IC_CON_BUS_CLEAR_CTRL;
+	if (ic_con & dev->con_bits->bus_clear_ctrl)
+		dev->master_cfg |= dev->con_bits->bus_clear_ctrl;
 
 	return i2c_dw_init_recovery_info(dev);
 }
diff --git a/drivers/i2c/busses/i2c-designware-pcidrv.c b/drivers/i2c/busses/i2c-designware-pcidrv.c
index 468287922363..fc73106fb0f9 100644
--- a/drivers/i2c/busses/i2c-designware-pcidrv.c
+++ b/drivers/i2c/busses/i2c-designware-pcidrv.c
@@ -246,6 +246,8 @@ static int i2c_dw_pci_probe(struct pci_dev *pdev,
 
 	pci_set_drvdata(pdev, dev);
 
+	i2c_dw_select_variant(dev);
+
 	if (controller->setup) {
 		r = controller->setup(pdev, controller);
 		if (r)
diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index 447af5523c2e..42b34c678146 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -156,6 +156,8 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
 	dev->flags = flags;
 	platform_set_drvdata(pdev, dev);
 
+	i2c_dw_select_variant(dev);
+
 	ret = dw_i2c_plat_request_regs(dev);
 	if (ret)
 		return ret;
diff --git a/drivers/i2c/busses/i2c-designware-slave.c b/drivers/i2c/busses/i2c-designware-slave.c
index 0abcc7757b23..0985e907c9c3 100644
--- a/drivers/i2c/busses/i2c-designware-slave.c
+++ b/drivers/i2c/busses/i2c-designware-slave.c
@@ -65,7 +65,7 @@ int i2c_dw_unreg_slave(struct i2c_client *slave)
 
 static u32 i2c_dw_read_clear_intrbits_slave(struct dw_i2c_dev *dev)
 {
-	unsigned int stat, dummy;
+	unsigned int stat;
 
 	/*
 	 * The IC_INTR_STAT register just indicates "enabled" interrupts.
@@ -89,23 +89,23 @@ static u32 i2c_dw_read_clear_intrbits_slave(struct dw_i2c_dev *dev)
 	 * Instead, use the separately-prepared IC_CLR_* registers.
 	 */
 	if (stat & DW_IC_INTR_TX_ABRT)
-		regmap_read(dev->map, DW_IC_CLR_TX_ABRT, &dummy);
+		i2c_dw_ack_intr(dev, DW_INTR_IDX_TX_ABRT);
 	if (stat & DW_IC_INTR_RX_UNDER)
-		regmap_read(dev->map, DW_IC_CLR_RX_UNDER, &dummy);
+		i2c_dw_ack_intr(dev, DW_INTR_IDX_RX_UNDER);
 	if (stat & DW_IC_INTR_RX_OVER)
-		regmap_read(dev->map, DW_IC_CLR_RX_OVER, &dummy);
+		i2c_dw_ack_intr(dev, DW_INTR_IDX_RX_OVER);
 	if (stat & DW_IC_INTR_TX_OVER)
-		regmap_read(dev->map, DW_IC_CLR_TX_OVER, &dummy);
+		i2c_dw_ack_intr(dev, DW_INTR_IDX_TX_OVER);
 	if (stat & DW_IC_INTR_RX_DONE)
-		regmap_read(dev->map, DW_IC_CLR_RX_DONE, &dummy);
+		i2c_dw_ack_intr(dev, DW_INTR_IDX_RX_DONE);
 	if (stat & DW_IC_INTR_ACTIVITY)
-		regmap_read(dev->map, DW_IC_CLR_ACTIVITY, &dummy);
+		i2c_dw_ack_intr(dev, DW_INTR_IDX_ACTIVITY);
 	if (stat & DW_IC_INTR_STOP_DET)
-		regmap_read(dev->map, DW_IC_CLR_STOP_DET, &dummy);
+		i2c_dw_ack_intr(dev, DW_INTR_IDX_STOP_DET);
 	if (stat & DW_IC_INTR_START_DET)
-		regmap_read(dev->map, DW_IC_CLR_START_DET, &dummy);
+		i2c_dw_ack_intr(dev, DW_INTR_IDX_START_DET);
 	if (stat & DW_IC_INTR_GEN_CALL)
-		regmap_read(dev->map, DW_IC_CLR_GEN_CALL, &dummy);
+		i2c_dw_ack_intr(dev, DW_INTR_IDX_GEN_CALL);
 
 	return stat;
 }
@@ -155,7 +155,7 @@ irqreturn_t i2c_dw_isr_slave(struct dw_i2c_dev *dev)
 
 	if (stat & DW_IC_INTR_RD_REQ) {
 		if (slave_activity) {
-			regmap_read(dev->map, DW_IC_CLR_RD_REQ, &tmp);
+			i2c_dw_ack_intr(dev, DW_INTR_IDX_RD_REQ);
 
 			if (!(dev->status & STATUS_READ_IN_PROGRESS)) {
 				i2c_slave_event(dev->slave,
@@ -185,8 +185,8 @@ void i2c_dw_configure_slave(struct dw_i2c_dev *dev)
 
 	dev->functionality |= I2C_FUNC_SLAVE;
 
-	dev->slave_cfg = DW_IC_CON_RX_FIFO_FULL_HLD_CTRL |
-			 DW_IC_CON_RESTART_EN | DW_IC_CON_STOP_DET_IFADDRESSED;
+	dev->slave_cfg = dev->con_bits->rx_fifo_full_hld_ctrl |
+			 dev->con_bits->restart_en | dev->con_bits->stop_det_ifaddressed;
 }
 EXPORT_SYMBOL_GPL(i2c_dw_configure_slave);
 
diff --git a/include/linux/designware_i2c.h b/include/linux/designware_i2c.h
index 53f37f18a722..994e0e5ea623 100644
--- a/include/linux/designware_i2c.h
+++ b/include/linux/designware_i2c.h
@@ -11,48 +11,103 @@
 #include <linux/bits.h>
 
 /*
- * Registers offset
+ * Logical register IDs. Each ID is resolved to a physical offset via a
+ * per-variant table (see dw_i2c_reg_offsets[] below); regmap backends
+ * (dw_reg_read()/dw_reg_write() and the Xe I2C_REG() macro) perform that
+ * lookup so callers never need to know the real offset.
  */
-#define DW_IC_CON				0x00
-#define DW_IC_TAR				0x04
-#define DW_IC_SAR				0x08
-#define DW_IC_DATA_CMD				0x10
-#define DW_IC_SS_SCL_HCNT			0x14
-#define DW_IC_SS_SCL_LCNT			0x18
-#define DW_IC_FS_SCL_HCNT			0x1c
-#define DW_IC_FS_SCL_LCNT			0x20
-#define DW_IC_HS_SCL_HCNT			0x24
-#define DW_IC_HS_SCL_LCNT			0x28
-#define DW_IC_INTR_STAT				0x2c
-#define DW_IC_INTR_MASK				0x30
-#define DW_IC_RAW_INTR_STAT			0x34
-#define DW_IC_RX_TL				0x38
-#define DW_IC_TX_TL				0x3c
-#define DW_IC_CLR_INTR				0x40
-#define DW_IC_CLR_RX_UNDER			0x44
-#define DW_IC_CLR_RX_OVER			0x48
-#define DW_IC_CLR_TX_OVER			0x4c
-#define DW_IC_CLR_RD_REQ			0x50
-#define DW_IC_CLR_TX_ABRT			0x54
-#define DW_IC_CLR_RX_DONE			0x58
-#define DW_IC_CLR_ACTIVITY			0x5c
-#define DW_IC_CLR_STOP_DET			0x60
-#define DW_IC_CLR_START_DET			0x64
-#define DW_IC_CLR_GEN_CALL			0x68
-#define DW_IC_ENABLE				0x6c
-#define DW_IC_STATUS				0x70
-#define DW_IC_TXFLR				0x74
-#define DW_IC_RXFLR				0x78
-#define DW_IC_SDA_HOLD				0x7c
-#define DW_IC_TX_ABRT_SOURCE			0x80
-#define DW_IC_ENABLE_STATUS			0x9c
-#define DW_IC_CLR_RESTART_DET			0xa8
-#define DW_IC_SMBUS_INTR_STAT			0xc8
-#define DW_IC_SMBUS_INTR_MASK			0xcc
-#define DW_IC_CLR_SMBUS_INTR			0xd4
-#define DW_IC_COMP_PARAM_1			0xf4
-#define DW_IC_COMP_VERSION			0xf8
-#define DW_IC_COMP_TYPE				0xfc
+enum dw_ic_reg_id {
+	DW_IC_CON,
+	DW_IC_TAR,
+	DW_IC_SAR,
+	DW_IC_DATA_CMD,
+	DW_IC_SS_SCL_HCNT,
+	DW_IC_SS_SCL_LCNT,
+	DW_IC_FS_SCL_HCNT,
+	DW_IC_FS_SCL_LCNT,
+	DW_IC_HS_SCL_HCNT,
+	DW_IC_HS_SCL_LCNT,
+	DW_IC_INTR_STAT,
+	DW_IC_INTR_MASK,
+	DW_IC_RAW_INTR_STAT,
+	DW_IC_RX_TL,
+	DW_IC_TX_TL,
+	DW_IC_CLR_INTR,
+	DW_IC_CLR_RX_UNDER,
+	DW_IC_CLR_RX_OVER,
+	DW_IC_CLR_TX_OVER,
+	DW_IC_CLR_RD_REQ,
+	DW_IC_CLR_TX_ABRT,
+	DW_IC_CLR_RX_DONE,
+	DW_IC_CLR_ACTIVITY,
+	DW_IC_CLR_STOP_DET,
+	DW_IC_CLR_START_DET,
+	DW_IC_CLR_GEN_CALL,
+	DW_IC_ENABLE,
+	DW_IC_STATUS,
+	DW_IC_TXFLR,
+	DW_IC_RXFLR,
+	DW_IC_SDA_HOLD,
+	DW_IC_TX_ABRT_SOURCE,
+	DW_IC_ENABLE_STATUS,
+	DW_IC_CLR_RESTART_DET,
+	DW_IC_SMBUS_INTR_STAT,
+	DW_IC_SMBUS_INTR_MASK,
+	DW_IC_CLR_SMBUS_INTR,
+	DW_IC_COMP_PARAM_1,
+	DW_IC_COMP_VERSION,
+	DW_IC_COMP_TYPE,
+	AMD_UCSI_INTR_REG,
+	DW_IC_REG_MAX
+};
+
+/*
+ * Default "snps,designware-i2c" register offsets, indexed by
+ * enum dw_ic_reg_id.
+ */
+static const __maybe_unused u32 dw_i2c_reg_offsets[DW_IC_REG_MAX] = {
+	[DW_IC_CON]			= 0x00,
+	[DW_IC_TAR]			= 0x04,
+	[DW_IC_SAR]			= 0x08,
+	[DW_IC_DATA_CMD]		= 0x10,
+	[DW_IC_SS_SCL_HCNT]		= 0x14,
+	[DW_IC_SS_SCL_LCNT]		= 0x18,
+	[DW_IC_FS_SCL_HCNT]		= 0x1c,
+	[DW_IC_FS_SCL_LCNT]		= 0x20,
+	[DW_IC_HS_SCL_HCNT]		= 0x24,
+	[DW_IC_HS_SCL_LCNT]		= 0x28,
+	[DW_IC_INTR_STAT]		= 0x2c,
+	[DW_IC_INTR_MASK]		= 0x30,
+	[DW_IC_RAW_INTR_STAT]		= 0x34,
+	[DW_IC_RX_TL]			= 0x38,
+	[DW_IC_TX_TL]			= 0x3c,
+	[DW_IC_CLR_INTR]		= 0x40,
+	[DW_IC_CLR_RX_UNDER]		= 0x44,
+	[DW_IC_CLR_RX_OVER]		= 0x48,
+	[DW_IC_CLR_TX_OVER]		= 0x4c,
+	[DW_IC_CLR_RD_REQ]		= 0x50,
+	[DW_IC_CLR_TX_ABRT]		= 0x54,
+	[DW_IC_CLR_RX_DONE]		= 0x58,
+	[DW_IC_CLR_ACTIVITY]		= 0x5c,
+	[DW_IC_CLR_STOP_DET]		= 0x60,
+	[DW_IC_CLR_START_DET]		= 0x64,
+	[DW_IC_CLR_GEN_CALL]		= 0x68,
+	[DW_IC_ENABLE]			= 0x6c,
+	[DW_IC_STATUS]			= 0x70,
+	[DW_IC_TXFLR]			= 0x74,
+	[DW_IC_RXFLR]			= 0x78,
+	[DW_IC_SDA_HOLD]		= 0x7c,
+	[DW_IC_TX_ABRT_SOURCE]		= 0x80,
+	[DW_IC_ENABLE_STATUS]		= 0x9c,
+	[DW_IC_CLR_RESTART_DET]		= 0xa8,
+	[DW_IC_SMBUS_INTR_STAT]		= 0xc8,
+	[DW_IC_SMBUS_INTR_MASK]		= 0xcc,
+	[DW_IC_CLR_SMBUS_INTR]		= 0xd4,
+	[DW_IC_COMP_PARAM_1]		= 0xf4,
+	[DW_IC_COMP_VERSION]		= 0xf8,
+	[DW_IC_COMP_TYPE]		= 0xfc,
+	[AMD_UCSI_INTR_REG]		= 0x474,
+};
 
 /* DW_IC_CON bits */
 #define DW_IC_CON_MASTER			BIT(0)

-- 
2.53.0