[PATCH v2 1/4] drm: Helper for lspcon in drm_dp_dual_mode

Shashank Sharma
2016-06-21T14:51:33Z

This patch adds lspcon support in dp_dual_mode helper.
lspcon is essentially a dp->hdmi dongle with dual personality.

LS mode: It works as a passive dongle, by level shifting DP++
signals to HDMI signals, in LS mode.
PCON mode: It works as a protocol converter active dongle
in pcon mode, by converting DP++ outputs to HDMI 2.0 outputs.

This patch adds support for lspcon detection and mode set
switch operations, as a dp dual mode dongle.

v2: Addressed review comments from Ville
- add adaptor id for lspcon devices (0x08), use it to identify lspcon
- change function names
old: drm_lspcon_get_current_mode/drm_lspcon_change_mode
new: drm_lspcon_get_mode/drm_lspcon_set_mode
- change drm_lspcon_get_mode type to int, to match
drm_dp_dual_mode_get_tmds_output
- change 'err' to 'ret' to match the rest of the functions
- remove pointless typecasting during call to dual_mode_read
- fix the but while setting value of data, while writing lspcon mode
- fix indentation
- change mdelay(10) -> msleep(10)
- return ETIMEDOUT instead of EFAULT, when lspcon mode change times out
- Add an empty line to separate std regs macros and lspcon regs macros
Indent bit definition

Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
---
drivers/gpu/drm/drm_dp_dual_mode_helper.c | 103 ++++++++++++++++++++++++++++++
include/drm/drm_dp_dual_mode_helper.h | 25 ++++++++
2 files changed, 128 insertions(+)

diff --git a/drivers/gpu/drm/drm_dp_dual_mode_helper.c b/drivers/gpu/drm/drm_dp_dual_mode_helper.c
index a7b2a75..404e715 100644
--- a/drivers/gpu/drm/drm_dp_dual_mode_helper.c
+++ b/drivers/gpu/drm/drm_dp_dual_mode_helper.c
@@ -148,6 +148,14 @@ static bool is_type2_adaptor(uint8_t adaptor_id)
DP_DUAL_MODE_REV_TYPE2);
}

+bool is_lspcon_adaptor(const char hdmi_id[DP_DUAL_MODE_HDMI_ID_LEN],
+ const uint8_t adaptor_id)
+{
+ return is_hdmi_adaptor(hdmi_id) &&
+ (adaptor_id == (DP_DUAL_MODE_REV_TYPE2 |
+ DP_DUAL_MODE_TYPE_TYPE2 | DP_DUAL_MODE_TYPE_LSPCON));
+}
+
/**
* drm_dp_dual_mode_detect - Identify the DP dual mode adaptor
* @adapter: I2C adapter for the DDC bus
@@ -203,6 +211,8 @@ enum drm_dp_dual_mode_type drm_dp_dual_mode_detect(struct i2c_adapter *adapter)
ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_ADAPTOR_ID,
&adaptor_id, sizeof(adaptor_id));
if (ret == 0) {
+ if (is_lspcon_adaptor(hdmi_id, adaptor_id))
+ return DRM_DP_DUAL_MODE_LSPCON;
if (is_type2_adaptor(adaptor_id)) {
if (is_hdmi_adaptor(hdmi_id))
return DRM_DP_DUAL_MODE_TYPE2_HDMI;
@@ -364,3 +374,96 @@ const char *drm_dp_get_dual_mode_type_name(enum drm_dp_dual_mode_type type)
}
}
EXPORT_SYMBOL(drm_dp_get_dual_mode_type_name);
+
+/**
+ * drm_lspcon_get_current_mode: Get LSPCON's current mode of operation by
+ * by reading offset (0x80, 0x41)
+ * @i2c_adapter: I2C-over-aux adapter
+ * @current_mode: out vaiable, current lspcon mode of operation
+ *
+ * Returns:
+ * 0 on success, sets the current_mode value to appropriate mode
+ * -error on failure
+ */
+int drm_lspcon_get_mode(struct i2c_adapter *adapter,
+ enum drm_lspcon_mode *current_mode)
+{
+ u8 data;
+ int ret = 0;
+
+ if (!current_mode) {
+ DRM_ERROR("NULL input\n");
+ return -EINVAL;
+ }
+
+ /* Read Status: i2c over aux */
+ ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_LSPCON_CURRENT_MODE,
+ (void *)&data, sizeof(data));
+ if (ret < 0) {
+ DRM_ERROR("LSPCON read(0x80, 0x41) failed\n");
+ return -EFAULT;
+ }
+
+ if (data & DP_DUAL_MODE_LSPCON_MODE_MASK)
+ *current_mode = DRM_LSPCON_MODE_PCON;
+ else
+ *current_mode = DRM_LSPCON_MODE_LS;
+ return 0;
+}
+EXPORT_SYMBOL(drm_lspcon_get_mode);
+
+/**
+ * drm_lspcon_change_mode: Change LSPCON's mode of operation by
+ * by writing offset (0x80, 0x40)
+ * @i2c_adapter: I2C-over-aux adapter
+ * @reqd_mode: required mode of operation
+ *
+ * Returns:
+ * 0 on success, -error on failure/timeout
+ */
+int drm_lspcon_set_mode(struct i2c_adapter *adapter,
+ enum drm_lspcon_mode reqd_mode)
+{
+ u8 data = 0;
+ int ret;
+ int time_out = 200;
+ enum drm_lspcon_mode changed_mode;
+
+ if (reqd_mode == DRM_LSPCON_MODE_PCON)
+ data = DP_DUAL_MODE_LSPCON_MODE_MASK;
+
+ /* Change mode */
+ ret = drm_dp_dual_mode_write(adapter, DP_DUAL_MODE_LSPCON_MODE_CHANGE,
+ &data, sizeof(data));
+ if (ret < 0) {
+ DRM_ERROR("LSPCON mode change failed\n");
+ return ret;
+ }
+
+ /*
+ * Confirm mode change by reading the status bit.
+ * Sometimes, it takes a while to change the mode,
+ * so wait and retry until time out or done.
+ */
+ do {
+ ret = drm_lspcon_get_mode(adapter, &changed_mode);
+ if (ret) {
+ DRM_ERROR("cant confirm LSPCON mode change\n");
+ return ret;
+ } else {
+ if (changed_mode != reqd_mode) {
+ msleep(10);
+ time_out -= 10;
+ } else {
+ DRM_DEBUG_KMS("LSPCON mode changed to %s\n",
+ reqd_mode == DRM_LSPCON_MODE_LS ?
+ "LS" : "PCON");
+ return 0;
+ }
+ }
+ } while (time_out);
+
+ DRM_ERROR("LSPCON mode change timed out\n");
+ return -ETIMEDOUT;
+}
+EXPORT_SYMBOL(drm_lspcon_set_mode);
diff --git a/include/drm/drm_dp_dual_mode_helper.h b/include/drm/drm_dp_dual_mode_helper.h
index e8a9dfd..441c6cb 100644
--- a/include/drm/drm_dp_dual_mode_helper.h
+++ b/include/drm/drm_dp_dual_mode_helper.h
@@ -24,6 +24,7 @@
#define DRM_DP_DUAL_MODE_HELPER_H

#include <linux/types.h>
+#include <drm/drm_edid.h>

/*
* Optional for type 1 DVI adaptors
@@ -40,6 +41,7 @@
#define DP_DUAL_MODE_REV_TYPE2 0x00
#define DP_DUAL_MODE_TYPE_MASK 0xf0
#define DP_DUAL_MODE_TYPE_TYPE2 0xa0
+#define DP_DUAL_MODE_TYPE_LSPCON 0x08
#define DP_DUAL_MODE_IEEE_OUI 0x11 /* 11-13*/
#define DP_DUAL_IEEE_OUI_LEN 3
#define DP_DUAL_DEVICE_ID 0x14 /* 14-19 */
@@ -55,6 +57,10 @@
#define DP_DUAL_MODE_CEC_ENABLE 0x01
#define DP_DUAL_MODE_I2C_SPEED_CTRL 0x22

+#define DP_DUAL_MODE_LSPCON_MODE_CHANGE 0x40
+#define DP_DUAL_MODE_LSPCON_CURRENT_MODE 0x41
+#define DP_DUAL_MODE_LSPCON_MODE_MASK 0x1
+
struct i2c_adapter;

ssize_t drm_dp_dual_mode_read(struct i2c_adapter *adapter,
@@ -63,6 +69,19 @@ ssize_t drm_dp_dual_mode_write(struct i2c_adapter *adapter,
u8 offset, const void *buffer, size_t size);

/**
+* enum drm_lspcon_mode
+* @lspcon_mode_ls: Level shifter mode of LSPCON
+* which drives DP++ to HDMI 1.4 conversion.
+* @lspcon_mode_pcon: Protocol converter mode of LSPCON
+* which drives DP++ to HDMI 2.0 active conversion.
+*/
+enum drm_lspcon_mode {
+ DRM_LSPCON_MODE_INVALID,
+ DRM_LSPCON_MODE_LS,
+ DRM_LSPCON_MODE_PCON,
+};
+
+/**
* enum drm_dp_dual_mode_type - Type of the DP dual mode adaptor
* @DRM_DP_DUAL_MODE_NONE: No DP dual mode adaptor
* @DRM_DP_DUAL_MODE_UNKNOWN: Could be either none or type 1 DVI adaptor
@@ -70,6 +89,7 @@ ssize_t drm_dp_dual_mode_write(struct i2c_adapter *adapter,
* @DRM_DP_DUAL_MODE_TYPE1_HDMI: Type 1 HDMI adaptor
* @DRM_DP_DUAL_MODE_TYPE2_DVI: Type 2 DVI adaptor
* @DRM_DP_DUAL_MODE_TYPE2_HDMI: Type 2 HDMI adaptor
+ * @DRM_DP_DUAL_MODE_TYPE2_LSPCON: Level shifter /protocol converter
*/
enum drm_dp_dual_mode_type {
DRM_DP_DUAL_MODE_NONE,
@@ -78,6 +98,7 @@ enum drm_dp_dual_mode_type {
DRM_DP_DUAL_MODE_TYPE1_HDMI,
DRM_DP_DUAL_MODE_TYPE2_DVI,
DRM_DP_DUAL_MODE_TYPE2_HDMI,
+ DRM_DP_DUAL_MODE_LSPCON,
};

enum drm_dp_dual_mode_type drm_dp_dual_mode_detect(struct i2c_adapter *adapter);
@@ -89,4 +110,8 @@ int drm_dp_dual_mode_set_tmds_output(enum drm_dp_dual_mode_type type,
struct i2c_adapter *adapter, bool enable);
const char *drm_dp_get_dual_mode_type_name(enum drm_dp_dual_mode_type type);

+int drm_lspcon_get_mode(struct i2c_adapter *adapter,
+ enum drm_lspcon_mode *current_mode);
+int drm_lspcon_set_mode(struct i2c_adapter *adapter,
+ enum drm_lspcon_mode reqd_mode);
#endif
--
1.9.1