From 69c05eb2d8421cbe96c2c66ea6e3223d25928d92 Mon Sep 17 00:00:00 2001
From: Jani Nikula <jani.nikula@intel.com>
Date: Tue, 27 Aug 2013 15:12:19 +0300
Subject: [PATCH] drm/i915: add MIPI DSI command sending routines
MIME-Version: 1.0
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v2: Rebase due to register bit definition change.

v3: Mostly based on Ville's review comments.
 - Use size_t for length all around.
 - Reuse dsi_vc_send_short in dsi_vc_send_long.
 - Remove stale/incorrect comments.
 - Reverse special packet sent interrupt check.
 - Use DSI controller regs for reading, not adapter.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
 drivers/gpu/drm/i915/Makefile        |   1 +
 drivers/gpu/drm/i915/intel_dsi_cmd.c | 427 +++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_dsi_cmd.h | 109 +++++++++
 3 files changed, 537 insertions(+)
 create mode 100644 drivers/gpu/drm/i915/intel_dsi_cmd.c
 create mode 100644 drivers/gpu/drm/i915/intel_dsi_cmd.h

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index b8449a8..8bffd29 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -21,6 +21,7 @@ i915-y := i915_drv.o i915_dma.o i915_irq.o \
 	  intel_display.o \
 	  intel_crt.o \
 	  intel_lvds.o \
+	  intel_dsi_cmd.o \
 	  intel_bios.o \
 	  intel_ddi.o \
 	  intel_dp.o \
diff --git a/drivers/gpu/drm/i915/intel_dsi_cmd.c b/drivers/gpu/drm/i915/intel_dsi_cmd.c
new file mode 100644
index 0000000..86577a0
--- /dev/null
+++ b/drivers/gpu/drm/i915/intel_dsi_cmd.c
@@ -0,0 +1,427 @@
+/*
+ * Copyright © 2013 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Author: Jani Nikula <jani.nikula@intel.com>
+ */
+
+#include <linux/export.h>
+#include <drm/drmP.h>
+#include <drm/drm_crtc.h>
+#include <video/mipi_display.h>
+#include "i915_drv.h"
+#include "intel_drv.h"
+#include "intel_dsi.h"
+#include "intel_dsi_cmd.h"
+
+/*
+ * XXX: MIPI_DATA_ADDRESS, MIPI_DATA_LENGTH, MIPI_COMMAND_LENGTH, and
+ * MIPI_COMMAND_ADDRESS registers.
+ *
+ * Apparently these registers provide a MIPI adapter level way to send (lots of)
+ * commands and data to the receiver, without having to write the commands and
+ * data to MIPI_{HS,LP}_GEN_{CTRL,DATA} registers word by word.
+ *
+ * Presumably for anything other than MIPI_DCS_WRITE_MEMORY_START and
+ * MIPI_DCS_WRITE_MEMORY_CONTINUE (which are used to update the external
+ * framebuffer in command mode displays) these are just an optimization that can
+ * come later.
+ *
+ * For memory writes, these should probably be used for performance.
+ */
+
+static void print_stat(struct intel_dsi *intel_dsi)
+{
+	struct drm_encoder *encoder = &intel_dsi->base.base;
+	struct drm_device *dev = encoder->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
+	enum pipe pipe = intel_crtc->pipe;
+	u32 val;
+
+	val = I915_READ(MIPI_INTR_STAT(pipe));
+
+#define STAT_BIT(val, bit) (val) & (bit) ? " " #bit : ""
+	DRM_DEBUG_KMS("MIPI_INTR_STAT(%d) = %08x"
+		      "%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s"
+		      "\n", pipe, val,
+		      STAT_BIT(val, TEARING_EFFECT),
+		      STAT_BIT(val, SPL_PKT_SENT_INTERRUPT),
+		      STAT_BIT(val, GEN_READ_DATA_AVAIL),
+		      STAT_BIT(val, LP_GENERIC_WR_FIFO_FULL),
+		      STAT_BIT(val, HS_GENERIC_WR_FIFO_FULL),
+		      STAT_BIT(val, RX_PROT_VIOLATION),
+		      STAT_BIT(val, RX_INVALID_TX_LENGTH),
+		      STAT_BIT(val, ACK_WITH_NO_ERROR),
+		      STAT_BIT(val, TURN_AROUND_ACK_TIMEOUT),
+		      STAT_BIT(val, LP_RX_TIMEOUT),
+		      STAT_BIT(val, HS_TX_TIMEOUT),
+		      STAT_BIT(val, DPI_FIFO_UNDERRUN),
+		      STAT_BIT(val, LOW_CONTENTION),
+		      STAT_BIT(val, HIGH_CONTENTION),
+		      STAT_BIT(val, TXDSI_VC_ID_INVALID),
+		      STAT_BIT(val, TXDSI_DATA_TYPE_NOT_RECOGNISED),
+		      STAT_BIT(val, TXCHECKSUM_ERROR),
+		      STAT_BIT(val, TXECC_MULTIBIT_ERROR),
+		      STAT_BIT(val, TXECC_SINGLE_BIT_ERROR),
+		      STAT_BIT(val, TXFALSE_CONTROL_ERROR),
+		      STAT_BIT(val, RXDSI_VC_ID_INVALID),
+		      STAT_BIT(val, RXDSI_DATA_TYPE_NOT_REGOGNISED),
+		      STAT_BIT(val, RXCHECKSUM_ERROR),
+		      STAT_BIT(val, RXECC_MULTIBIT_ERROR),
+		      STAT_BIT(val, RXECC_SINGLE_BIT_ERROR),
+		      STAT_BIT(val, RXFALSE_CONTROL_ERROR),
+		      STAT_BIT(val, RXHS_RECEIVE_TIMEOUT_ERROR),
+		      STAT_BIT(val, RX_LP_TX_SYNC_ERROR),
+		      STAT_BIT(val, RXEXCAPE_MODE_ENTRY_ERROR),
+		      STAT_BIT(val, RXEOT_SYNC_ERROR),
+		      STAT_BIT(val, RXSOT_SYNC_ERROR),
+		      STAT_BIT(val, RXSOT_ERROR));
+#undef STAT_BIT
+}
+
+enum dsi_type {
+	DSI_DCS,
+	DSI_GENERIC,
+};
+
+/* enable or disable command mode hs transmissions */
+void dsi_hs_mode_enable(struct intel_dsi *intel_dsi, bool enable)
+{
+	struct drm_encoder *encoder = &intel_dsi->base.base;
+	struct drm_device *dev = encoder->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
+	enum pipe pipe = intel_crtc->pipe;
+	u32 temp;
+	u32 mask = DBI_FIFO_EMPTY;
+
+	if (wait_for((I915_READ(MIPI_GEN_FIFO_STAT(pipe)) & mask) == mask, 50))
+		DRM_ERROR("Timeout waiting for DBI FIFO empty\n");
+
+	temp = I915_READ(MIPI_HS_LP_DBI_ENABLE(pipe));
+	temp &= DBI_HS_LP_MODE_MASK;
+	I915_WRITE(MIPI_HS_LP_DBI_ENABLE(pipe), enable ? DBI_HS_MODE : DBI_LP_MODE);
+
+	intel_dsi->hs = enable;
+}
+
+static int dsi_vc_send_short(struct intel_dsi *intel_dsi, int channel,
+			     u8 data_type, u16 data)
+{
+	struct drm_encoder *encoder = &intel_dsi->base.base;
+	struct drm_device *dev = encoder->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
+	enum pipe pipe = intel_crtc->pipe;
+	u32 ctrl_reg;
+	u32 ctrl;
+	u32 mask;
+
+	DRM_DEBUG_KMS("channel %d, data_type %d, data %04x\n",
+		      channel, data_type, data);
+
+	if (intel_dsi->hs) {
+		ctrl_reg = MIPI_HS_GEN_CTRL(pipe);
+		mask = HS_CTRL_FIFO_FULL;
+	} else {
+		ctrl_reg = MIPI_LP_GEN_CTRL(pipe);
+		mask = LP_CTRL_FIFO_FULL;
+	}
+
+	if (wait_for((I915_READ(MIPI_GEN_FIFO_STAT(pipe)) & mask) == 0, 50)) {
+		DRM_ERROR("Timeout waiting for HS/LP CTRL FIFO !full\n");
+		print_stat(intel_dsi);
+	}
+
+	/*
+	 * Note: This function is also used for long packets, with length passed
+	 * as data, since SHORT_PACKET_PARAM_SHIFT ==
+	 * LONG_PACKET_WORD_COUNT_SHIFT.
+	 */
+	ctrl = data << SHORT_PACKET_PARAM_SHIFT |
+		channel << VIRTUAL_CHANNEL_SHIFT |
+		data_type << DATA_TYPE_SHIFT;
+
+	I915_WRITE(ctrl_reg, ctrl);
+
+	return 0;
+}
+
+static int dsi_vc_send_long(struct intel_dsi *intel_dsi, int channel,
+			    u8 data_type, const u8 *data, size_t len)
+{
+	struct drm_encoder *encoder = &intel_dsi->base.base;
+	struct drm_device *dev = encoder->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
+	enum pipe pipe = intel_crtc->pipe;
+	u32 data_reg;
+	size_t i, j, n;
+	u32 mask;
+
+	DRM_DEBUG_KMS("channel %d, data_type %d, len %04x\n",
+		      channel, data_type, len);
+
+	if (intel_dsi->hs) {
+		data_reg = MIPI_HS_GEN_DATA(pipe);
+		mask = HS_DATA_FIFO_FULL;
+	} else {
+		data_reg = MIPI_LP_GEN_DATA(pipe);
+		mask = LP_DATA_FIFO_FULL;
+	}
+
+	if (wait_for((I915_READ(MIPI_GEN_FIFO_STAT(pipe)) & mask) == 0, 50))
+		DRM_ERROR("Timeout waiting for HS/LP DATA FIFO !full\n");
+
+	for (i = 0; i < len; i += n) {
+		u32 val = 0;
+		n = min_t(size_t, len - i, 4);
+
+		for (j = 0; j < n; j++)
+			val |= *data++ << 8 * j;
+
+		I915_WRITE(data_reg, val);
+		/* XXX: check for data fifo full, once that is set, write 4
+		 * dwords, then wait for not set, then continue. */
+	}
+
+	return dsi_vc_send_short(intel_dsi, channel, data_type, len);
+}
+
+static int dsi_vc_write_common(struct intel_dsi *intel_dsi,
+			       int channel, const u8 *data, size_t len,
+			       enum dsi_type type)
+{
+	int ret;
+
+	if (len == 0) {
+		BUG_ON(type == DSI_GENERIC);
+		ret = dsi_vc_send_short(intel_dsi, channel,
+					MIPI_DSI_GENERIC_SHORT_WRITE_0_PARAM,
+					0);
+	} else if (len == 1) {
+		ret = dsi_vc_send_short(intel_dsi, channel,
+					type == DSI_GENERIC ?
+					MIPI_DSI_GENERIC_SHORT_WRITE_1_PARAM :
+					MIPI_DSI_DCS_SHORT_WRITE, data[0]);
+	} else if (len == 2) {
+		ret = dsi_vc_send_short(intel_dsi, channel,
+					type == DSI_GENERIC ?
+					MIPI_DSI_GENERIC_SHORT_WRITE_2_PARAM :
+					MIPI_DSI_DCS_SHORT_WRITE_PARAM,
+					(data[1] << 8) | data[0]);
+	} else {
+		ret = dsi_vc_send_long(intel_dsi, channel,
+				       type == DSI_GENERIC ?
+				       MIPI_DSI_GENERIC_LONG_WRITE :
+				       MIPI_DSI_DCS_LONG_WRITE, data, len);
+	}
+
+	return ret;
+}
+
+int dsi_vc_dcs_write(struct intel_dsi *intel_dsi, int channel,
+		     const u8 *data, size_t len)
+{
+	return dsi_vc_write_common(intel_dsi, channel, data, len, DSI_DCS);
+}
+
+int dsi_vc_generic_write(struct intel_dsi *intel_dsi, int channel,
+			 const u8 *data, size_t len)
+{
+	return dsi_vc_write_common(intel_dsi, channel, data, len, DSI_GENERIC);
+}
+
+static int dsi_vc_dcs_send_read_request(struct intel_dsi *intel_dsi,
+					int channel, u8 dcs_cmd)
+{
+	return dsi_vc_send_short(intel_dsi, channel, MIPI_DSI_DCS_READ,
+				 dcs_cmd);
+}
+
+static int dsi_vc_generic_send_read_request(struct intel_dsi *intel_dsi,
+					    int channel, u8 *reqdata,
+					    size_t reqlen)
+{
+	u16 data;
+	u8 data_type;
+
+	switch (reqlen) {
+	case 0:
+		data_type = MIPI_DSI_GENERIC_READ_REQUEST_0_PARAM;
+		data = 0;
+		break;
+	case 1:
+		data_type = MIPI_DSI_GENERIC_READ_REQUEST_1_PARAM;
+		data = reqdata[0];
+		break;
+	case 2:
+		data_type = MIPI_DSI_GENERIC_READ_REQUEST_2_PARAM;
+		data = (reqdata[1] << 8) | reqdata[0];
+		break;
+	default:
+		BUG();
+	}
+
+	return dsi_vc_send_short(intel_dsi, channel, data_type, data);
+}
+
+static int dsi_read_data_return(struct intel_dsi *intel_dsi,
+				u8 *buf, size_t buflen)
+{
+	struct drm_encoder *encoder = &intel_dsi->base.base;
+	struct drm_device *dev = encoder->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
+	enum pipe pipe = intel_crtc->pipe;
+	size_t i, len = 0;
+	u32 data_reg, val;
+
+	if (intel_dsi->hs) {
+		data_reg = MIPI_HS_GEN_DATA(pipe);
+	} else {
+		data_reg = MIPI_LP_GEN_DATA(pipe);
+	}
+
+	while (len < buflen) {
+		val = I915_READ(data_reg);
+		for (i = 0; i < 4 && len < buflen; i++, len++)
+			buf[len] = val >> 8 * i;
+	}
+
+	return len;
+}
+
+int dsi_vc_dcs_read(struct intel_dsi *intel_dsi, int channel, u8 dcs_cmd,
+		    u8 *buf, size_t buflen)
+{
+	struct drm_encoder *encoder = &intel_dsi->base.base;
+	struct drm_device *dev = encoder->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
+	enum pipe pipe = intel_crtc->pipe;
+	u32 mask;
+	int ret;
+
+	/*
+	 * XXX: should issue multiple read requests and reads if request is
+	 * longer than MIPI_MAX_RETURN_PKT_SIZE
+	 */
+
+	I915_WRITE(MIPI_INTR_STAT(pipe), GEN_READ_DATA_AVAIL);
+
+	ret = dsi_vc_dcs_send_read_request(intel_dsi, channel, dcs_cmd);
+	if (ret)
+		return ret;
+
+	mask = GEN_READ_DATA_AVAIL;
+	if (wait_for((I915_READ(MIPI_INTR_STAT(pipe)) & mask) == mask, 50))
+		DRM_ERROR("Timeout waiting for read data.\n");
+
+	ret = dsi_read_data_return(intel_dsi, buf, buflen);
+	if (ret < 0)
+		return ret;
+
+	if (ret != buflen)
+		return -EIO;
+
+	return 0;
+}
+
+int dsi_vc_generic_read(struct intel_dsi *intel_dsi, int channel,
+			u8 *reqdata, size_t reqlen, u8 *buf, size_t buflen)
+{
+	struct drm_encoder *encoder = &intel_dsi->base.base;
+	struct drm_device *dev = encoder->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
+	enum pipe pipe = intel_crtc->pipe;
+	u32 mask;
+	int ret;
+
+	/*
+	 * XXX: should issue multiple read requests and reads if request is
+	 * longer than MIPI_MAX_RETURN_PKT_SIZE
+	 */
+
+	I915_WRITE(MIPI_INTR_STAT(pipe), GEN_READ_DATA_AVAIL);
+
+	ret = dsi_vc_generic_send_read_request(intel_dsi, channel, reqdata,
+					       reqlen);
+	if (ret)
+		return ret;
+
+	mask = GEN_READ_DATA_AVAIL;
+	if (wait_for((I915_READ(MIPI_INTR_STAT(pipe)) & mask) == mask, 50))
+		DRM_ERROR("Timeout waiting for read data.\n");
+
+	ret = dsi_read_data_return(intel_dsi, buf, buflen);
+	if (ret < 0)
+		return ret;
+
+	if (ret != buflen)
+		return -EIO;
+
+	return 0;
+}
+
+/*
+ * send a video mode command
+ *
+ * XXX: commands with data in MIPI_DPI_DATA?
+ */
+int dpi_send_cmd(struct intel_dsi *intel_dsi, u32 cmd)
+{
+	struct drm_encoder *encoder = &intel_dsi->base.base;
+	struct drm_device *dev = encoder->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
+	enum pipe pipe = intel_crtc->pipe;
+	u32 mask;
+
+	/* XXX: pipe, hs */
+	if (intel_dsi->hs)
+		cmd &= ~DPI_LP_MODE;
+	else
+		cmd |= DPI_LP_MODE;
+
+	/* DPI virtual channel?! */
+
+	mask = DPI_FIFO_EMPTY;
+	if (wait_for((I915_READ(MIPI_GEN_FIFO_STAT(pipe)) & mask) == mask, 50))
+		DRM_ERROR("Timeout waiting for DPI FIFO empty.\n");
+
+	/* clear bit */
+	I915_WRITE(MIPI_INTR_STAT(pipe), SPL_PKT_SENT_INTERRUPT);
+
+	/* XXX: old code skips write if control unchanged */
+	if (cmd == I915_READ(MIPI_DPI_CONTROL(pipe)))
+		DRM_ERROR("Same special packet %02x twice in a row.\n", cmd);
+
+	I915_WRITE(MIPI_DPI_CONTROL(pipe), cmd);
+
+	mask = SPL_PKT_SENT_INTERRUPT;
+	if (wait_for((I915_READ(MIPI_INTR_STAT(pipe)) & mask) == mask, 100))
+		DRM_ERROR("Video mode command 0x%08x send failed.\n", cmd);
+
+	return 0;
+}
diff --git a/drivers/gpu/drm/i915/intel_dsi_cmd.h b/drivers/gpu/drm/i915/intel_dsi_cmd.h
new file mode 100644
index 0000000..714a49a
--- /dev/null
+++ b/drivers/gpu/drm/i915/intel_dsi_cmd.h
@@ -0,0 +1,109 @@
+/*
+ * Copyright © 2013 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Author: Jani Nikula <jani.nikula@intel.com>
+ */
+
+#ifndef _INTEL_DSI_DSI_H
+#define _INTEL_DSI_DSI_H
+
+#include <drm/drmP.h>
+#include <drm/drm_crtc.h>
+#include <video/mipi_display.h>
+#include "i915_drv.h"
+#include "intel_drv.h"
+#include "intel_dsi.h"
+
+void dsi_hs_mode_enable(struct intel_dsi *intel_dsi, bool enable);
+
+int dsi_vc_dcs_write(struct intel_dsi *intel_dsi, int channel,
+		     const u8 *data, size_t len);
+
+int dsi_vc_generic_write(struct intel_dsi *intel_dsi, int channel,
+			 const u8 *data, size_t len);
+
+int dsi_vc_dcs_read(struct intel_dsi *intel_dsi, int channel, u8 dcs_cmd,
+		    u8 *buf, size_t buflen);
+
+int dsi_vc_generic_read(struct intel_dsi *intel_dsi, int channel,
+			u8 *reqdata, size_t reqlen, u8 *buf, size_t buflen);
+
+int dpi_send_cmd(struct intel_dsi *intel_dsi, u32 cmd);
+
+/* XXX: questionable write helpers */
+static inline int dsi_vc_dcs_write_0(struct intel_dsi *intel_dsi,
+				     int channel, u8 dcs_cmd)
+{
+	return dsi_vc_dcs_write(intel_dsi, channel, &dcs_cmd, 1);
+}
+
+static inline int dsi_vc_dcs_write_1(struct intel_dsi *intel_dsi,
+				     int channel, u8 dcs_cmd, u8 param)
+{
+	u8 buf[2] = { dcs_cmd, param };
+	return dsi_vc_dcs_write(intel_dsi, channel, buf, 2);
+}
+
+static inline int dsi_vc_generic_write_0(struct intel_dsi *intel_dsi,
+					 int channel)
+{
+	return dsi_vc_generic_write(intel_dsi, channel, NULL, 0);
+}
+
+static inline int dsi_vc_generic_write_1(struct intel_dsi *intel_dsi,
+					 int channel, u8 param)
+{
+	return dsi_vc_generic_write(intel_dsi, channel, &param, 1);
+}
+
+static inline int dsi_vc_generic_write_2(struct intel_dsi *intel_dsi,
+					 int channel, u8 param1, u8 param2)
+{
+	u8 buf[2] = { param1, param2 };
+	return dsi_vc_generic_write(intel_dsi, channel, buf, 2);
+}
+
+/* XXX: questionable read helpers */
+static inline int dsi_vc_generic_read_0(struct intel_dsi *intel_dsi,
+					int channel, u8 *buf, size_t buflen)
+{
+	return dsi_vc_generic_read(intel_dsi, channel, NULL, 0, buf, buflen);
+}
+
+static inline int dsi_vc_generic_read_1(struct intel_dsi *intel_dsi,
+					int channel, u8 param, u8 *buf,
+					size_t buflen)
+{
+	return dsi_vc_generic_read(intel_dsi, channel, &param, 1, buf, buflen);
+}
+
+static inline int dsi_vc_generic_read_2(struct intel_dsi *intel_dsi,
+					int channel, u8 param1, u8 param2,
+					u8 *buf, size_t buflen)
+{
+	u8 req[2] = { param1, param2 };
+
+	return dsi_vc_generic_read(intel_dsi, channel, req, 2, buf, buflen);
+}
+
+
+#endif /* _INTEL_DSI_DSI_H */
-- 
2.7.4