PCI/pwrctrl: tc9563: Rely on regmap APIs

Replace the custom tc9563_pwrctrl_i2c_{read,write,bulk_write} functions
with standard regmap APIs. The device uses 24-bit big-endian register
addresses and 32-bit little-endian register values over I2C, which is
directly supported by regmap.

This removes the open-coded I2C transfer handling and lets the regmap
core handle formatting, locking, and multi-register coalescing.

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Link: https://patch.msgid.link/20260729-pci-pwrctrl-tc956x-regmap-v1-1-20ce61a3ce12@oss.qualcomm.com

2 files changed, 44 insertions, 110 deletions

diff --git a/drivers/pci/pwrctrl/Kconfig b/drivers/pci/pwrctrl/Kconfig
index 9eec767cda86..1952ab4f29b6 100644
--- a/drivers/pci/pwrctrl/Kconfig
+++ b/drivers/pci/pwrctrl/Kconfig
@@ -29,6 +29,7 @@ config PCI_PWRCTRL_TC9563
 	select PCI_PWRCTRL
 	default m if ARCH_QCOM
 	depends on I2C
+	select REGMAP_I2C
 	help
 	  Say Y here to enable the PCI Power Control driver of TC9563 PCIe
 	  switch.
diff --git a/drivers/pci/pwrctrl/pci-pwrctrl-tc9563.c b/drivers/pci/pwrctrl/pci-pwrctrl-tc9563.c
index fd53a7db9875..d2a0c4f8c03e 100644
--- a/drivers/pci/pwrctrl/pci-pwrctrl-tc9563.c
+++ b/drivers/pci/pwrctrl/pci-pwrctrl-tc9563.c
@@ -16,10 +16,10 @@
 #include <linux/pci.h>
 #include <linux/pci-pwrctrl.h>
 #include <linux/platform_device.h>
+#include <linux/regmap.h>
 #include <linux/regulator/consumer.h>
 #include <linux/string.h>
 #include <linux/types.h>
-#include <linux/unaligned.h>
 
 #include "../pci.h"
 
@@ -70,11 +70,6 @@
 
 #define TC9563_L0S_L1_DELAY_UNIT_NS	256  /* Each unit represents 256 ns */
 
-struct tc9563_pwrctrl_reg_setting {
-	unsigned int offset;
-	unsigned int val;
-};
-
 enum tc9563_pwrctrl_ports {
 	TC9563_USP,
 	TC9563_DSP1,
@@ -111,13 +106,14 @@ struct tc9563_pwrctrl {
 	struct gpio_desc *reset_gpio;
 	struct i2c_adapter *adapter;
 	struct i2c_client *client;
+	struct regmap *regmap;
 };
 
 /*
  * downstream port power off sequence, hardcoding the address
  * as we don't know register names for these register offsets.
  */
-static const struct tc9563_pwrctrl_reg_setting common_pwroff_seq[] = {
+static const struct reg_sequence common_pwroff_seq[] = {
 	{0x82900c, 0x1},
 	{0x829010, 0x1},
 	{0x829018, 0x0},
@@ -140,7 +136,7 @@ static const struct tc9563_pwrctrl_reg_setting common_pwroff_seq[] = {
 	{0x829114, 0x1},
 };
 
-static const struct tc9563_pwrctrl_reg_setting dsp1_pwroff_seq[] = {
+static const struct reg_sequence dsp1_pwroff_seq[] = {
 	{TC9563_PORT_ACCESS_ENABLE, 0x2},
 	{TC9563_PORT_LANE_ACCESS_ENABLE, 0x3},
 	{TC9563_POWER_CONTROL, 0x014f4804},
@@ -148,7 +144,7 @@ static const struct tc9563_pwrctrl_reg_setting dsp1_pwroff_seq[] = {
 	{TC9563_PORT_ACCESS_ENABLE, 0x4},
 };
 
-static const struct tc9563_pwrctrl_reg_setting dsp2_pwroff_seq[] = {
+static const struct reg_sequence dsp2_pwroff_seq[] = {
 	{TC9563_PORT_ACCESS_ENABLE, 0x8},
 	{TC9563_PORT_LANE_ACCESS_ENABLE, 0x1},
 	{TC9563_POWER_CONTROL, 0x014f4804},
@@ -156,85 +152,11 @@ static const struct tc9563_pwrctrl_reg_setting dsp2_pwroff_seq[] = {
 	{TC9563_PORT_ACCESS_ENABLE, 0x8},
 };
 
-/*
- * Since all transfers are initiated by the probe, no locks are necessary,
- * as there are no concurrent calls.
- */
-static int tc9563_pwrctrl_i2c_write(struct i2c_client *client,
-				    u32 reg_addr, u32 reg_val)
-{
-	struct i2c_msg msg;
-	u8 msg_buf[7];
-	int ret;
-
-	msg.addr = client->addr;
-	msg.len = 7;
-	msg.flags = 0;
-
-	/* Big Endian for reg addr */
-	put_unaligned_be24(reg_addr, &msg_buf[0]);
-
-	/* Little Endian for reg val */
-	put_unaligned_le32(reg_val, &msg_buf[3]);
-
-	msg.buf = msg_buf;
-	ret = i2c_transfer(client->adapter, &msg, 1);
-	return ret == 1 ? 0 : ret;
-}
-
-static int tc9563_pwrctrl_i2c_read(struct i2c_client *client,
-				   u32 reg_addr, u32 *reg_val)
-{
-	struct i2c_msg msg[2];
-	u8 wr_data[3];
-	u32 rd_data;
-	int ret;
-
-	msg[0].addr = client->addr;
-	msg[0].len = 3;
-	msg[0].flags = 0;
-
-	/* Big Endian for reg addr */
-	put_unaligned_be24(reg_addr, &wr_data[0]);
-
-	msg[0].buf = wr_data;
-
-	msg[1].addr = client->addr;
-	msg[1].len = 4;
-	msg[1].flags = I2C_M_RD;
-
-	msg[1].buf = (u8 *)&rd_data;
-
-	ret = i2c_transfer(client->adapter, &msg[0], 2);
-	if (ret == 2) {
-		*reg_val = get_unaligned_le32(&rd_data);
-		return 0;
-	}
-
-	/* If only one message successfully completed, return -EIO */
-	return ret == 1 ? -EIO : ret;
-}
-
-static int tc9563_pwrctrl_i2c_bulk_write(struct i2c_client *client,
-				const struct tc9563_pwrctrl_reg_setting *seq,
-				int len)
-{
-	int ret, i;
-
-	for (i = 0; i < len; i++) {
-		ret = tc9563_pwrctrl_i2c_write(client, seq[i].offset, seq[i].val);
-		if (ret)
-			return ret;
-	}
-
-	return 0;
-}
-
 static int tc9563_pwrctrl_disable_port(struct tc9563_pwrctrl *tc9563,
 				       enum tc9563_pwrctrl_ports port)
 {
 	struct tc9563_pwrctrl_cfg *cfg = &tc9563->cfg[port];
-	const struct tc9563_pwrctrl_reg_setting *seq;
+	const struct reg_sequence *seq;
 	int ret, len;
 
 	if (!cfg->disable_port)
@@ -254,12 +176,12 @@ static int tc9563_pwrctrl_disable_port(struct tc9563_pwrctrl *tc9563,
 		return 0;
 	}
 
-	ret = tc9563_pwrctrl_i2c_bulk_write(tc9563->client, seq, len);
+	ret = regmap_multi_reg_write(tc9563->regmap, seq, len);
 	if (ret)
 		return ret;
 
-	return tc9563_pwrctrl_i2c_bulk_write(tc9563->client, common_pwroff_seq,
-					     ARRAY_SIZE(common_pwroff_seq));
+	return regmap_multi_reg_write(tc9563->regmap, common_pwroff_seq,
+				      ARRAY_SIZE(common_pwroff_seq));
 }
 
 static int tc9563_pwrctrl_set_port_l0s_l1_entry_delay(struct tc9563_pwrctrl *tc9563,
@@ -275,14 +197,13 @@ static int tc9563_pwrctrl_set_port_l0s_l1_entry_delay(struct tc9563_pwrctrl *tc9
 	/* convert to units of 256ns */
 	units = ns / TC9563_L0S_L1_DELAY_UNIT_NS;
 
-	ret = tc9563_pwrctrl_i2c_write(tc9563->client, TC9563_PORT_SELECT,
-				       BIT(port));
+	ret = regmap_write(tc9563->regmap, TC9563_PORT_SELECT, BIT(port));
 	if (ret)
 		return ret;
 
-	return tc9563_pwrctrl_i2c_write(tc9563->client,
-			is_l1 ? TC9563_PORT_L1_DELAY : TC9563_PORT_L0S_DELAY,
-			units);
+	return regmap_write(tc9563->regmap,
+			    is_l1 ? TC9563_PORT_L1_DELAY : TC9563_PORT_L0S_DELAY,
+			    units);
 }
 
 static int tc9563_pwrctrl_set_eth_l0s_l1_entry_delay(struct tc9563_pwrctrl *tc9563,
@@ -297,8 +218,7 @@ static int tc9563_pwrctrl_set_eth_l0s_l1_entry_delay(struct tc9563_pwrctrl *tc95
 	/* convert to units of 256ns */
 	units = ns / TC9563_L0S_L1_DELAY_UNIT_NS;
 
-	ret = tc9563_pwrctrl_i2c_read(tc9563->client, TC9563_EMBEDDED_ETH_DELAY,
-				      &rd_val);
+	ret = regmap_read(tc9563->regmap, TC9563_EMBEDDED_ETH_DELAY, &rd_val);
 	if (ret)
 		return ret;
 
@@ -309,8 +229,7 @@ static int tc9563_pwrctrl_set_eth_l0s_l1_entry_delay(struct tc9563_pwrctrl *tc95
 		rd_val = u32_replace_bits(rd_val, units,
 					  TC9563_ETH_L0S_DELAY_MASK);
 
-	return tc9563_pwrctrl_i2c_write(tc9563->client, TC9563_EMBEDDED_ETH_DELAY,
-					rd_val);
+	return regmap_write(tc9563->regmap, TC9563_EMBEDDED_ETH_DELAY, rd_val);
 }
 
 static int tc9563_pwrctrl_set_tx_amplitude(struct tc9563_pwrctrl *tc9563,
@@ -343,14 +262,14 @@ static int tc9563_pwrctrl_set_tx_amplitude(struct tc9563_pwrctrl *tc9563,
 		return -EINVAL;
 	}
 
-	struct tc9563_pwrctrl_reg_setting tx_amp_seq[] = {
+	struct reg_sequence tx_amp_seq[] = {
 		{TC9563_PORT_ACCESS_ENABLE, port_access},
 		{TC9563_PORT_LANE_ACCESS_ENABLE, 0x3},
 		{TC9563_TX_MARGIN, amp},
 	};
 
-	return tc9563_pwrctrl_i2c_bulk_write(tc9563->client, tx_amp_seq,
-					     ARRAY_SIZE(tx_amp_seq));
+	return regmap_multi_reg_write(tc9563->regmap, tx_amp_seq,
+				      ARRAY_SIZE(tx_amp_seq));
 }
 
 static int tc9563_pwrctrl_disable_dfe(struct tc9563_pwrctrl *tc9563,
@@ -383,7 +302,7 @@ static int tc9563_pwrctrl_disable_dfe(struct tc9563_pwrctrl *tc9563,
 		return -EINVAL;
 	}
 
-	struct tc9563_pwrctrl_reg_setting disable_dfe_seq[] = {
+	struct reg_sequence disable_dfe_seq[] = {
 		{TC9563_PORT_ACCESS_ENABLE, port_access},
 		{TC9563_PORT_LANE_ACCESS_ENABLE, lane_access},
 		{TC9563_DFE_ENABLE, 0x0},
@@ -397,15 +316,15 @@ static int tc9563_pwrctrl_disable_dfe(struct tc9563_pwrctrl *tc9563,
 		{TC9563_PHY_RATE_CHANGE_OVERRIDE, 0x0},
 	};
 
-	return tc9563_pwrctrl_i2c_bulk_write(tc9563->client, disable_dfe_seq,
-					     ARRAY_SIZE(disable_dfe_seq));
+	return regmap_multi_reg_write(tc9563->regmap, disable_dfe_seq,
+				      ARRAY_SIZE(disable_dfe_seq));
 }
 
 static int tc9563_pwrctrl_set_nfts(struct tc9563_pwrctrl *tc9563,
 				   enum tc9563_pwrctrl_ports port)
 {
 	u8 *nfts = tc9563->cfg[port].nfts;
-	struct tc9563_pwrctrl_reg_setting nfts_seq[] = {
+	struct reg_sequence nfts_seq[] = {
 		{TC9563_NFTS_2_5_GT, nfts[0]},
 		{TC9563_NFTS_5_GT, nfts[1]},
 	};
@@ -420,13 +339,12 @@ static int tc9563_pwrctrl_set_nfts(struct tc9563_pwrctrl *tc9563,
 		return 0;
 	}
 
-	ret =  tc9563_pwrctrl_i2c_write(tc9563->client, TC9563_PORT_SELECT,
-					BIT(port));
+	ret =  regmap_write(tc9563->regmap, TC9563_PORT_SELECT, BIT(port));
 	if (ret)
 		return ret;
 
-	return tc9563_pwrctrl_i2c_bulk_write(tc9563->client, nfts_seq,
-					     ARRAY_SIZE(nfts_seq));
+	return regmap_multi_reg_write(tc9563->regmap, nfts_seq,
+				      ARRAY_SIZE(nfts_seq));
 }
 
 static int tc9563_pwrctrl_assert_deassert_reset(struct tc9563_pwrctrl *tc9563,
@@ -434,14 +352,14 @@ static int tc9563_pwrctrl_assert_deassert_reset(struct tc9563_pwrctrl *tc9563,
 {
 	int ret, val;
 
-	ret = tc9563_pwrctrl_i2c_write(tc9563->client, TC9563_GPIO_CONFIG,
-				       TC9563_GPIO_MASK);
+	ret = regmap_write(tc9563->regmap, TC9563_GPIO_CONFIG,
+			   TC9563_GPIO_MASK);
 	if (ret)
 		return ret;
 
 	val = deassert ? TC9563_GPIO_DEASSERT_BITS : 0;
 
-	return tc9563_pwrctrl_i2c_write(tc9563->client, TC9563_RESET_GPIO, val);
+	return regmap_write(tc9563->regmap, TC9563_RESET_GPIO, val);
 }
 
 static int tc9563_pwrctrl_parse_device_dt(struct device_node *node,
@@ -572,6 +490,13 @@ power_off:
 	return ret;
 }
 
+static const struct regmap_config tc9563_regmap_config = {
+	.reg_bits = 24,
+	.val_bits = 32,
+	.reg_format_endian = REGMAP_ENDIAN_BIG,
+	.val_format_endian = REGMAP_ENDIAN_LITTLE,
+};
+
 static int tc9563_pwrctrl_probe(struct platform_device *pdev)
 {
 	struct device_node *node = pdev->dev.of_node;
@@ -602,6 +527,14 @@ static int tc9563_pwrctrl_probe(struct platform_device *pdev)
 		return PTR_ERR(tc9563->client);
 	}
 
+	tc9563->regmap = devm_regmap_init_i2c(tc9563->client,
+					      &tc9563_regmap_config);
+	if (IS_ERR(tc9563->regmap)) {
+		ret = dev_err_probe(dev, PTR_ERR(tc9563->regmap),
+				    "Failed to allocate register map\n");
+		goto remove_i2c;
+	}
+
 	for (int i = 0; i < ARRAY_SIZE(tc9563_supply_names); i++)
 		tc9563->supplies[i].supply = tc9563_supply_names[i];