[PATCH v5] drm/i915: Adding the parsing logic for the i2c element

[Jani Nikula <jani.nikula@intel.com>]

New sequence element for i2c is been added in the
mipi sequence block of the VBT. This patch parses
and executes the i2c sequence.

v2: Add i2c_put_adapter call(Jani), rebase

v3: corrected the retry loop(Jani), rebase

v4 by Jani:
 - don't put the adapter if get fails
 - print an error message if all retries exhausted
 - use a for loop
 - fix warnings for unused variables

v5 by Jani:
 - rebase on the skip i2c element patch

Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: vkorjani <vikas.korjani@intel.com>
Signed-off-by: Deepak M <m.deepak@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
 drivers/gpu/drm/i915/intel_dsi_panel_vbt.c | 58 ++++++++++++++++++++++++++++--
 1 file changed, 55 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c b/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
index 1d43e6f37fc1..213d9ef2d712 100644
--- a/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
+++ b/drivers/gpu/drm/i915/intel_dsi_panel_vbt.c
@@ -31,6 +31,7 @@
 #include <drm/drm_panel.h>
 #include <linux/slab.h>
 #include <video/mipi_display.h>
+#include <linux/i2c.h>
 #include <asm/intel-mid.h>
 #include <video/mipi_display.h>
 #include "i915_drv.h"
@@ -229,9 +230,60 @@ static const u8 *mipi_exec_gpio(struct intel_dsi *intel_dsi, const u8 *data)
 	return data;
 }
 
-static const u8 *mipi_exec_i2c_skip(struct intel_dsi *intel_dsi, const u8 *data)
+static const u8 *mipi_exec_i2c(struct intel_dsi *intel_dsi, const u8 *data)
 {
-	return data + *(data + 6) + 7;
+	struct i2c_adapter *adapter;
+	int ret, i;
+	u8 reg_offset, payload_size;
+	struct i2c_msg msg;
+	u8 *transmit_buffer;
+	u8 flag, bus_number;
+	u16 slave_add;
+
+	flag = *data++;
+	data++; /* index, unused */
+	bus_number = *data++;
+	slave_add = *(u16 *)(data);
+	data += 2;
+	reg_offset = *data++;
+	payload_size = *data++;
+
+	adapter = i2c_get_adapter(bus_number);
+	if (!adapter) {
+		DRM_ERROR("i2c_get_adapter(%u)\n", bus_number);
+		goto out;
+	}
+
+	transmit_buffer = kmalloc(1 + payload_size, GFP_TEMPORARY);
+	if (!transmit_buffer)
+		goto out_put;
+
+	transmit_buffer[0] = reg_offset;
+	memcpy(&transmit_buffer[1], data, payload_size);
+
+	msg.addr = slave_add;
+	msg.flags = 0;
+	msg.len = payload_size + 1;
+	msg.buf = &transmit_buffer[0];
+
+	for (i = 0; i < 6; i++) {
+		ret = i2c_transfer(adapter, &msg, 1);
+		if (ret == 1) {
+			goto out_free;
+		} else if (ret == -EAGAIN) {
+			usleep_range(1000, 2500);
+		} else {
+			break;
+		}
+	}
+
+	DRM_ERROR("i2c transfer failed: %d\n", ret);
+out_free:
+	kfree(transmit_buffer);
+out_put:
+	i2c_put_adapter(adapter);
+out:
+	return data + payload_size;
 }
 
 typedef const u8 * (*fn_mipi_elem_exec)(struct intel_dsi *intel_dsi,
@@ -240,7 +292,7 @@ static const fn_mipi_elem_exec exec_elem[] = {
 	[MIPI_SEQ_ELEM_SEND_PKT] = mipi_exec_send_packet,
 	[MIPI_SEQ_ELEM_DELAY] = mipi_exec_delay,
 	[MIPI_SEQ_ELEM_GPIO] = mipi_exec_gpio,
-	[MIPI_SEQ_ELEM_I2C] = mipi_exec_i2c_skip,
+	[MIPI_SEQ_ELEM_I2C] = mipi_exec_i2c,
 };
 
 /*
-- 
2.1.4

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