[PATCH 3/9] drm/bridge: extract some Analogix I2C DP common code

[Icenowy Zheng]

Some code can be shared within different DP bridges by Analogix.

Extract them to a new module.

Signed-off-by: Icenowy Zheng <icenowy@xxxxxxx>
---
 drivers/gpu/drm/bridge/analogix/Kconfig       |   4 +
 drivers/gpu/drm/bridge/analogix/Makefile      |   2 +
 .../drm/bridge/analogix/analogix-anx78xx.c    | 146 +--------------
 .../drm/bridge/analogix/analogix-i2c-dptx.c   | 169 ++++++++++++++++++
 .../drm/bridge/analogix/analogix-i2c-dptx.h   |   2 +
 5 files changed, 178 insertions(+), 145 deletions(-)
 create mode 100644 drivers/gpu/drm/bridge/analogix/analogix-i2c-dptx.c

diff --git a/drivers/gpu/drm/bridge/analogix/Kconfig b/drivers/gpu/drm/bridge/analogix/Kconfig
index 27b37aa2ea77..eb893b465dd8 100644
--- a/drivers/gpu/drm/bridge/analogix/Kconfig
+++ b/drivers/gpu/drm/bridge/analogix/Kconfig
@@ -2,8 +2,12 @@ config DRM_ANALOGIX_DP
 	tristate
 	depends on DRM
 
+config DRM_ANALOGIX_DP_I2C
+	tristate
+
 config DRM_ANALOGIX_ANX78XX
 	tristate "Analogix ANX78XX bridge"
+	select DRM_ANALOGIX_DP_I2C
 	select DRM_KMS_HELPER
 	select REGMAP_I2C
 	---help---
diff --git a/drivers/gpu/drm/bridge/analogix/Makefile b/drivers/gpu/drm/bridge/analogix/Makefile
index eb41be845055..c37e2ded8ce3 100644
--- a/drivers/gpu/drm/bridge/analogix/Makefile
+++ b/drivers/gpu/drm/bridge/analogix/Makefile
@@ -1,3 +1,5 @@
 analogix_dp-objs := analogix_dp_core.o analogix_dp_reg.o
+analogix_dp_i2c-objs := analogix-i2c-dptx.o
 obj-$(CONFIG_DRM_ANALOGIX_DP) += analogix_dp.o
+obj-$(CONFIG_DRM_ANALOGIX_DP_I2C) += analogix_dp_i2c.o
 obj-$(CONFIG_DRM_ANALOGIX_ANX78XX) += analogix-anx78xx.o
diff --git a/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c b/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c
index f8433c93f463..bf8291d0ddd0 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix-anx78xx.c
@@ -45,8 +45,6 @@
 #define I2C_IDX_RX_P1		4
 
 #define XTAL_CLK		270 /* 27M */
-#define AUX_CH_BUFFER_SIZE	16
-#define AUX_WAIT_TIMEOUT_MS	15
 
 static const u8 anx78xx_i2c_addresses[] = {
 	[I2C_IDX_TX_P0] = TX_P0,
@@ -109,153 +107,11 @@ static int anx78xx_clear_bits(struct regmap *map, u8 reg, u8 mask)
 	return regmap_update_bits(map, reg, mask, 0);
 }
 
-static bool anx78xx_aux_op_finished(struct anx78xx *anx78xx)
-{
-	unsigned int value;
-	int err;
-
-	err = regmap_read(anx78xx->map[I2C_IDX_TX_P0], SP_DP_AUX_CH_CTRL2_REG,
-			  &value);
-	if (err < 0)
-		return false;
-
-	return (value & SP_AUX_EN) == 0;
-}
-
-static int anx78xx_aux_wait(struct anx78xx *anx78xx)
-{
-	unsigned long timeout;
-	unsigned int status;
-	int err;
-
-	timeout = jiffies + msecs_to_jiffies(AUX_WAIT_TIMEOUT_MS) + 1;
-
-	while (!anx78xx_aux_op_finished(anx78xx)) {
-		if (time_after(jiffies, timeout)) {
-			if (!anx78xx_aux_op_finished(anx78xx)) {
-				DRM_ERROR("Timed out waiting AUX to finish\n");
-				return -ETIMEDOUT;
-			}
-
-			break;
-		}
-
-		usleep_range(1000, 2000);
-	}
-
-	/* Read the AUX channel access status */
-	err = regmap_read(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_CH_STATUS_REG,
-			  &status);
-	if (err < 0) {
-		DRM_ERROR("Failed to read from AUX channel: %d\n", err);
-		return err;
-	}
-
-	if (status & SP_AUX_STATUS) {
-		DRM_ERROR("Failed to wait for AUX channel (status: %02x)\n",
-			  status);
-		return -ETIMEDOUT;
-	}
-
-	return 0;
-}
-
-static int anx78xx_aux_address(struct anx78xx *anx78xx, unsigned int addr)
-{
-	int err;
-
-	err = regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_ADDR_7_0_REG,
-			   addr & 0xff);
-	if (err)
-		return err;
-
-	err = regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_AUX_ADDR_15_8_REG,
-			   (addr & 0xff00) >> 8);
-	if (err)
-		return err;
-
-	/*
-	 * DP AUX CH Address Register #2, only update bits[3:0]
-	 * [7:4] RESERVED
-	 * [3:0] AUX_ADDR[19:16], Register control AUX CH address.
-	 */
-	err = regmap_update_bits(anx78xx->map[I2C_IDX_TX_P0],
-				 SP_AUX_ADDR_19_16_REG,
-				 SP_AUX_ADDR_19_16_MASK,
-				 (addr & 0xf0000) >> 16);
-
-	if (err)
-		return err;
-
-	return 0;
-}
-
 static ssize_t anx78xx_aux_transfer(struct drm_dp_aux *aux,
 				    struct drm_dp_aux_msg *msg)
 {
 	struct anx78xx *anx78xx = container_of(aux, struct anx78xx, aux);
-	u8 ctrl1 = msg->request;
-	u8 ctrl2 = SP_AUX_EN;
-	u8 *buffer = msg->buffer;
-	int err;
-
-	/* The DP AUX transmit and receive buffer has 16 bytes. */
-	if (WARN_ON(msg->size > AUX_CH_BUFFER_SIZE))
-		return -E2BIG;
-
-	/* Zero-sized messages specify address-only transactions. */
-	if (msg->size < 1)
-		ctrl2 |= SP_ADDR_ONLY;
-	else	/* For non-zero-sized set the length field. */
-		ctrl1 |= (msg->size - 1) << SP_AUX_LENGTH_SHIFT;
-
-	if ((msg->request & DP_AUX_I2C_READ) == 0) {
-		/* When WRITE | MOT write values to data buffer */
-		err = regmap_bulk_write(anx78xx->map[I2C_IDX_TX_P0],
-					SP_DP_BUF_DATA0_REG, buffer,
-					msg->size);
-		if (err)
-			return err;
-	}
-
-	/* Write address and request */
-	err = anx78xx_aux_address(anx78xx, msg->address);
-	if (err)
-		return err;
-
-	err = regmap_write(anx78xx->map[I2C_IDX_TX_P0], SP_DP_AUX_CH_CTRL1_REG,
-			   ctrl1);
-	if (err)
-		return err;
-
-	/* Start transaction */
-	err = regmap_update_bits(anx78xx->map[I2C_IDX_TX_P0],
-				 SP_DP_AUX_CH_CTRL2_REG, SP_ADDR_ONLY |
-				 SP_AUX_EN, ctrl2);
-	if (err)
-		return err;
-
-	err = anx78xx_aux_wait(anx78xx);
-	if (err)
-		return err;
-
-	msg->reply = DP_AUX_I2C_REPLY_ACK;
-
-	if ((msg->size > 0) && (msg->request & DP_AUX_I2C_READ)) {
-		/* Read values from data buffer */
-		err = regmap_bulk_read(anx78xx->map[I2C_IDX_TX_P0],
-				       SP_DP_BUF_DATA0_REG, buffer,
-				       msg->size);
-		if (err)
-			return err;
-	}
-
-	err = anx78xx_clear_bits(anx78xx->map[I2C_IDX_TX_P0],
-				 SP_DP_AUX_CH_CTRL2_REG, SP_ADDR_ONLY);
-	if (err)
-		return err;
-
-	return msg->size;
+	return anx_aux_transfer(anx78xx->map[I2C_IDX_TX_P0], msg);
 }
 
 static int anx78xx_set_hpd(struct anx78xx *anx78xx)
diff --git a/drivers/gpu/drm/bridge/analogix/analogix-i2c-dptx.c b/drivers/gpu/drm/bridge/analogix/analogix-i2c-dptx.c
new file mode 100644
index 000000000000..9cb30962032e
--- /dev/null
+++ b/drivers/gpu/drm/bridge/analogix/analogix-i2c-dptx.c
@@ -0,0 +1,169 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright(c) 2017 Icenowy Zheng <icenowy@xxxxxxx>
+ *
+ * Based on analogix-anx78xx.c, which is:
+ *   Copyright(c) 2016, Analogix Semiconductor. All rights reserved.
+ */
+
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#include <drm/drm.h>
+#include <drm/drmP.h>
+#include <drm/drm_dp_helper.h>
+
+#include "analogix-i2c-dptx.h"
+
+#define AUX_WAIT_TIMEOUT_MS	15
+#define AUX_CH_BUFFER_SIZE	16
+
+static int anx_clear_bits(struct regmap *map, u8 reg, u8 mask)
+{
+	return regmap_update_bits(map, reg, mask, 0);
+}
+
+static bool anx_aux_op_finished(struct regmap *map_dptx)
+{
+	unsigned int value;
+	int err;
+
+	err = regmap_read(map_dptx, SP_DP_AUX_CH_CTRL2_REG, &value);
+	if (err < 0)
+		return false;
+
+	return (value & SP_AUX_EN) == 0;
+}
+
+static int anx_aux_wait(struct regmap *map_dptx)
+{
+	unsigned long timeout;
+	unsigned int status;
+	int err;
+
+	timeout = jiffies + msecs_to_jiffies(AUX_WAIT_TIMEOUT_MS) + 1;
+
+	while (!anx_aux_op_finished(map_dptx)) {
+		if (time_after(jiffies, timeout)) {
+			if (!anx_aux_op_finished(map_dptx)) {
+				DRM_ERROR("Timed out waiting AUX to finish\n");
+				return -ETIMEDOUT;
+			}
+
+			break;
+		}
+
+		usleep_range(1000, 2000);
+	}
+
+	/* Read the AUX channel access status */
+	err = regmap_read(map_dptx, SP_AUX_CH_STATUS_REG, &status);
+	if (err < 0) {
+		DRM_ERROR("Failed to read from AUX channel: %d\n", err);
+		return err;
+	}
+
+	if (status & SP_AUX_STATUS) {
+		DRM_ERROR("Failed to wait for AUX channel (status: %02x)\n",
+			  status);
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
+static int anx_aux_address(struct regmap *map_dptx, unsigned int addr)
+{
+	int err;
+
+	err = regmap_write(map_dptx, SP_AUX_ADDR_7_0_REG, addr & 0xff);
+	if (err)
+		return err;
+
+	err = regmap_write(map_dptx, SP_AUX_ADDR_15_8_REG,
+			   (addr & 0xff00) >> 8);
+	if (err)
+		return err;
+
+	/*
+	 * DP AUX CH Address Register #2, only update bits[3:0]
+	 * [7:4] RESERVED
+	 * [3:0] AUX_ADDR[19:16], Register control AUX CH address.
+	 */
+	err = regmap_update_bits(map_dptx, SP_AUX_ADDR_19_16_REG,
+				 SP_AUX_ADDR_19_16_MASK,
+				 (addr & 0xf0000) >> 16);
+
+	if (err)
+		return err;
+
+	return 0;
+}
+
+ssize_t anx_aux_transfer(struct regmap *map_dptx, struct drm_dp_aux_msg *msg)
+{
+	u8 ctrl1 = msg->request;
+	u8 ctrl2 = SP_AUX_EN;
+	u8 *buffer = msg->buffer;
+	int err;
+
+	/* The DP AUX transmit and receive buffer has 16 bytes. */
+	if (WARN_ON(msg->size > AUX_CH_BUFFER_SIZE))
+		return -E2BIG;
+
+	/* Zero-sized messages specify address-only transactions. */
+	if (msg->size < 1)
+		ctrl2 |= SP_ADDR_ONLY;
+	else	/* For non-zero-sized set the length field. */
+		ctrl1 |= (msg->size - 1) << SP_AUX_LENGTH_SHIFT;
+
+	if ((msg->request & DP_AUX_I2C_READ) == 0) {
+		/* When WRITE | MOT write values to data buffer */
+		err = regmap_bulk_write(map_dptx,
+					SP_DP_BUF_DATA0_REG, buffer,
+					msg->size);
+		if (err)
+			return err;
+	}
+
+	/* Write address and request */
+	err = anx_aux_address(map_dptx, msg->address);
+	if (err)
+		return err;
+
+	err = regmap_write(map_dptx, SP_DP_AUX_CH_CTRL1_REG, ctrl1);
+	if (err)
+		return err;
+
+	/* Start transaction */
+	err = regmap_update_bits(map_dptx, SP_DP_AUX_CH_CTRL2_REG,
+				 SP_ADDR_ONLY | SP_AUX_EN, ctrl2);
+	if (err)
+		return err;
+
+	err = anx_aux_wait(map_dptx);
+	if (err)
+		return err;
+
+	msg->reply = DP_AUX_I2C_REPLY_ACK;
+
+	if ((msg->size > 0) && (msg->request & DP_AUX_I2C_READ)) {
+		/* Read values from data buffer */
+		err = regmap_bulk_read(map_dptx,
+				       SP_DP_BUF_DATA0_REG, buffer,
+				       msg->size);
+		if (err)
+			return err;
+	}
+
+	err = anx_clear_bits(map_dptx, SP_DP_AUX_CH_CTRL2_REG, SP_ADDR_ONLY);
+	if (err)
+		return err;
+
+	return msg->size;
+}
+EXPORT_SYMBOL(anx_aux_transfer);
+
+MODULE_DESCRIPTION("Analogix DisplayPort Transmitter common code");
+MODULE_AUTHOR("Icenowy Zheng <icenowy@xxxxxxx>");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/gpu/drm/bridge/analogix/analogix-i2c-dptx.h b/drivers/gpu/drm/bridge/analogix/analogix-i2c-dptx.h
index bc0831b127bf..c2ca854613a0 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix-i2c-dptx.h
+++ b/drivers/gpu/drm/bridge/analogix/analogix-i2c-dptx.h
@@ -245,4 +245,6 @@
 /* DP AUX Buffer Data Registers */
 #define SP_DP_BUF_DATA0_REG		0xf0
 
+ssize_t anx_aux_transfer(struct regmap *map_dptx, struct drm_dp_aux_msg *msg);
+
 #endif
-- 
2.18.1