On Mon, 02 May 2016, ville.syrjala@xxxxxxxxxxxxxxx wrote: > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > Add a helper which aids in the identification of DP dual mode > (aka. DP++) adaptors. There are several types of adaptors > specified: type 1 DVI, type 1 HDMI, type 2 DVI, type 2 HDMI > > Type 1 adaptors have a max TMDS clock limit of 165MHz, type 2 adaptors > may go as high as 300MHz and they provide a register informing the > source device what the actual limit is. Supposedly also type 1 adaptors > may optionally implement this register. This TMDS clock limit is the > main reason why we need to identify these adaptors. > > Type 1 adaptors provide access to their internal registers and the sink > DDC bus through I2C. Type 2 adaptors provide this access both via I2C > and I2C-over-AUX. A type 2 source device may choose to implement either > of these methods. If a source device implements the I2C-over-AUX > method, then the driver will obviously need specific support for such > adaptors since the port is driven like an HDMI port, but DDC > communication happes over the AUX channel. > > This helper should be enough to identify the adaptor type (some > type 1 DVI adaptors may be a slight exception) and the maximum TMDS > clock limit. Another feature that may be available is control over > the TMDS output buffers on the adaptor, possibly allowing for some > power saving when the TMDS link is down. > > Other user controllable features that may be available in the adaptors > are downstream i2c bus speed control when using i2c-over-aux, and > some control over the CEC pin. I chose not to provide any helper > functions for those since I have no use for them in i915 at this time. > The rest of the registers in the adaptor are mostly just information, > eg. IEEE OUI, hardware and firmware revision, etc. > > v2: Pass adaptor type to helper functions to ease driver implementation > Fix a bunch of typoes (Paulo) > Add DRM_DP_DUAL_MODE_UNKNOWN for the case where we don't (yet) know > the type (Paulo) > Reject 0x00 and 0xff DP_DUAL_MODE_MAX_TMDS_CLOCK values (Paulo) > Adjust drm_dp_dual_mode_detect() type2 vs. type1 detection to > ease future LSPCON enabling > Remove the unused DP_DUAL_MODE_LAST_RESERVED define > > Cc: stable@xxxxxxxxxxxxxxx > Cc: Tore Anderson <tore@xxxxxx> > Cc: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx> > Cc: Shashank Sharma <shashank.sharma@xxxxxxxxx> > Cc: Daniel Vetter <daniel.vetter@xxxxxxxx> > Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > --- > drivers/gpu/drm/Makefile | 2 +- > drivers/gpu/drm/drm_dp_dual_mode_helper.c | 356 ++++++++++++++++++++++++++++++ > include/drm/drm_dp_dual_mode_helper.h | 83 +++++++ > 3 files changed, 440 insertions(+), 1 deletion(-) > create mode 100644 drivers/gpu/drm/drm_dp_dual_mode_helper.c > create mode 100644 include/drm/drm_dp_dual_mode_helper.h > > diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile > index 1a26b4eb1ce0..29f2ee9b9534 100644 > --- a/drivers/gpu/drm/Makefile > +++ b/drivers/gpu/drm/Makefile > @@ -23,7 +23,7 @@ drm-$(CONFIG_AGP) += drm_agpsupport.o > > drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_probe_helper.o \ > drm_plane_helper.o drm_dp_mst_topology.o drm_atomic_helper.o \ > - drm_kms_helper_common.o > + drm_kms_helper_common.o drm_dp_dual_mode_helper.o > > drm_kms_helper-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o > drm_kms_helper-$(CONFIG_DRM_FBDEV_EMULATION) += drm_fb_helper.o > diff --git a/drivers/gpu/drm/drm_dp_dual_mode_helper.c b/drivers/gpu/drm/drm_dp_dual_mode_helper.c > new file mode 100644 > index 000000000000..949c0fbeb542 > --- /dev/null > +++ b/drivers/gpu/drm/drm_dp_dual_mode_helper.c > @@ -0,0 +1,356 @@ > +/* > + * Copyright © 2016 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 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 COPYRIGHT HOLDER(S) OR AUTHOR(S) 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. > + */ > + > +#include <linux/errno.h> > +#include <linux/export.h> > +#include <linux/i2c.h> > +#include <linux/slab.h> > +#include <linux/string.h> > +#include <drm/drm_dp_dual_mode_helper.h> > +#include <drm/drmP.h> > + > +/** > + * DOC: DP dual mode (aka. DP++) adaptor helpers > + * > + * Helper functions to deal with DP dual mode adaptors. > + * > + * Type 1: > + * Adaptor registers (if any) and the sink DDC bus may be accessed via I2C. > + * > + * Type 2: > + * Adaptor registers and sink DDC bus can be accessed either via I2C or > + * I2C-over-AUX. Source devices may choose to implement either of these > + * access methods. > + */ > + > +#define DP_DUAL_MODE_SLAVE_ADDRESS 0x40 > + > +/** > + * drm_dp_dual_mode_read - Read from the DP dual mode adaptor register(s) > + * adapter: I2C adapter for the DDC bus > + * offset: register offset > + * buffer: buffer for return data > + * size: sizo of the buffer The parameters need to be prefixed with @ in kernel-doc. Same across the patch series. BR, Jani. > + * > + * Reads @size bytes from the DP dual mode adaptor registers > + * starting at @offset. > + * > + * Returns: > + * 0 on success, negative error code on failure > + */ > +ssize_t drm_dp_dual_mode_read(struct i2c_adapter *adapter, > + u8 offset, void *buffer, size_t size) > +{ > + struct i2c_msg msgs[] = { > + { > + .addr = DP_DUAL_MODE_SLAVE_ADDRESS, > + .flags = 0, > + .len = 1, > + .buf = &offset, > + }, > + { > + .addr = DP_DUAL_MODE_SLAVE_ADDRESS, > + .flags = I2C_M_RD, > + .len = size, > + .buf = buffer, > + }, > + }; > + int ret; > + > + ret = i2c_transfer(adapter, msgs, ARRAY_SIZE(msgs)); > + if (ret < 0) > + return ret; > + if (ret != ARRAY_SIZE(msgs)) > + return -EPROTO; > + > + return 0; > +} > + > +/** > + * drm_dp_dual_mode_write - Write to the DP dual mode adaptor register(s) > + * adapter: I2C adapter for the DDC bus > + * offset: register offset > + * buffer: buffer for write data > + * size: sizo of the buffer > + * > + * Writes @size bytes to the DP dual mode adaptor registers > + * starting at @offset. > + * > + * Returns: > + * 0 on success, negative error code on failure > + */ > +ssize_t drm_dp_dual_mode_write(struct i2c_adapter *adapter, > + u8 offset, const void *buffer, size_t size) > +{ > + struct i2c_msg msg = { > + .addr = DP_DUAL_MODE_SLAVE_ADDRESS, > + .flags = 0, > + .len = 1 + size, > + .buf = NULL, > + }; > + void *data; > + int ret; > + > + data = kmalloc(msg.len, GFP_TEMPORARY); > + if (!data) > + return -ENOMEM; > + > + msg.buf = data; > + > + memcpy(data, &offset, 1); > + memcpy(data + 1, buffer, size); > + > + ret = i2c_transfer(adapter, &msg, 1); > + > + kfree(data); > + > + if (ret < 0) > + return ret; > + if (ret != 1) > + return -EPROTO; > + > + return 0; > +} > +EXPORT_SYMBOL(drm_dp_dual_mode_write); > + > +static bool is_hdmi_adaptor(const char hdmi_id[DP_DUAL_MODE_HDMI_ID_LEN]) > +{ > + static const char dp_dual_mode_hdmi_id[DP_DUAL_MODE_HDMI_ID_LEN] = > + "DP-HDMI ADAPTOR\x04"; > + > + return memcmp(hdmi_id, dp_dual_mode_hdmi_id, > + sizeof(dp_dual_mode_hdmi_id)) == 0; > +} > + > +static bool is_type2_adaptor(uint8_t adaptor_id) > +{ > + return adaptor_id == (DP_DUAL_MODE_TYPE_TYPE2 | > + DP_DUAL_MODE_REV_TYPE2); > +} > + > +/** > + * drm_dp_dual_mode_detect - Identify the DP dual mode adaptor > + * adapter: I2C adapter for the DDC bus > + * > + * Attempt to identify the type of the DP dual mode adaptor used. > + * > + * Note that when the answer is @DRM_DP_DUAL_MODE_NONE it's not > + * certain whether we're dealing with a native HDMI port or > + * a type 1 DVI dual mode adaptor. The driver will have to use > + * some other hardware/driver specific mechanism to make that > + * distinction. > + * > + * Returns: > + * The type of the DP dual mode adaptor used > + */ > +enum drm_dp_dual_mode_type drm_dp_dual_mode_detect(struct i2c_adapter *adapter) > +{ > + char hdmi_id[DP_DUAL_MODE_HDMI_ID_LEN] = {}; > + uint8_t adaptor_id = 0x00; > + ssize_t ret; > + > + /* > + * Let's see if the adaptor is there the by reading the > + * HDMI ID registers. > + * > + * Note that type 1 DVI adaptors are not required to implemnt > + * any registers, and that presents a problem for detection. > + * If the i2c transfer is nacked, we may or may not be dealing > + * with a type 1 DVI adaptor. Some other mechanism of detecting > + * the presence of the adaptor is required. One way would be > + * to check the state of the CONFIG1 pin, Another method would > + * simply require the driver to know whether the port is a DP++ > + * port or a native HDMI port. Both of these methods are entirely > + * hardware/driver specific so we can't deal with them here. > + */ > + ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_HDMI_ID, > + hdmi_id, sizeof(hdmi_id)); > + if (ret) > + return DRM_DP_DUAL_MODE_UNKNOWN; > + > + /* > + * Sigh. Some (maybe all?) type 1 adaptors are broken and ack > + * the offset but ignore it, and instead they just always return > + * data from the start of the HDMI ID buffer. So for a broken > + * type 1 HDMI adaptor a single byte read will always give us > + * 0x44, and for a type 1 DVI adaptor it should give 0x00 > + * (assuming it implements any registers). Fortunately neither > + * of those values will match the type 2 signature of the > + * DP_DUAL_MODE_ADAPTOR_ID register so we can proceed with > + * the type 2 adaptor detection safely even in the presence > + * of broken type 1 adaptors. > + */ > + ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_ADAPTOR_ID, > + &adaptor_id, sizeof(adaptor_id)); > + if (ret == 0) { > + if (is_type2_adaptor(adaptor_id) && is_hdmi_adaptor(hdmi_id)) > + return DRM_DP_DUAL_MODE_TYPE2_HDMI; > + else if (is_type2_adaptor(adaptor_id)) > + return DRM_DP_DUAL_MODE_TYPE2_DVI; > + } > + > + if (is_hdmi_adaptor(hdmi_id)) > + return DRM_DP_DUAL_MODE_TYPE1_HDMI; > + else > + return DRM_DP_DUAL_MODE_TYPE1_DVI; > +} > +EXPORT_SYMBOL(drm_dp_dual_mode_detect); > + > +/** > + * drm_dp_dual_mode_max_tmds_clock - Max TMDS clock for DP dual mode adaptor > + * type: DP dual mode adaptor type > + * adapter: I2C adapter for the DDC bus > + * > + * Determine the max TMDS clock the adaptor supports based on the > + * type of the dual mode adaptor and the DP_DUAL_MODE_MAX_TMDS_CLOCK > + * register (on type2 adaptors). As some type 1 adaptors have > + * problems with registers (see comments in drm_dp_dual_mode_detect()) > + * we don't read the register on those, instead we simply assume > + * a 165 MHz limit based on the specification. > + * > + * Returns: > + * Maximum supported TMDS clock rate for the DP dual mode adaptor in kHz. > + */ > +int drm_dp_dual_mode_max_tmds_clock(enum drm_dp_dual_mode_type type, > + struct i2c_adapter *adapter) > +{ > + uint8_t max_tmds_clock; > + ssize_t ret; > + > + /* native HDMI so no limit */ > + if (type == DRM_DP_DUAL_MODE_NONE) > + return 0; > + > + /* > + * Type 1 adaptors are limited to 165MHz > + * Type 2 adaptors can tells us their limit > + */ > + if (type < DRM_DP_DUAL_MODE_TYPE2_DVI) > + return 165000; > + > + ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_MAX_TMDS_CLOCK, > + &max_tmds_clock, sizeof(max_tmds_clock)); > + if (ret || max_tmds_clock == 0x00 || max_tmds_clock == 0xff) > + return 165000; > + > + return max_tmds_clock * 5000 / 2; > +} > +EXPORT_SYMBOL(drm_dp_dual_mode_max_tmds_clock); > + > +/** > + * drm_dp_dual_mode_get_tmds_output - Get the state of the TMDS output buffers in the DP dual mode adaptor > + * type: DP dual mode adaptor type > + * adapter: I2C adapter for the DDC bus > + * enabled: current state of the TMDS output buffers > + * > + * Get the state of the TMDS output buffers in the adaptor. For > + * type2 adaptors this is queried from the DP_DUAL_MODE_TMDS_OEN > + * register. As some type 1 adaptors have problems with registers > + * (see comments in drm_dp_dual_mode_detect()) we don't read the > + * register on those, instead we simply assume that the buffers > + * are always enabled. > + * > + * Returns: > + * 0 on success, negative error code on failure > + */ > +int drm_dp_dual_mode_get_tmds_output(enum drm_dp_dual_mode_type type, > + struct i2c_adapter *adapter, > + bool *enabled) > +{ > + uint8_t tmds_oen; > + ssize_t ret; > + > + if (type < DRM_DP_DUAL_MODE_TYPE2_DVI) { > + *enabled = true; > + return 0; > + } > + > + ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_TMDS_OEN, > + &tmds_oen, sizeof(tmds_oen)); > + if (ret) > + return ret; > + > + *enabled = !(tmds_oen & DP_DUAL_MODE_TMDS_DISABLE); > + > + return 0; > +} > +EXPORT_SYMBOL(drm_dp_dual_mode_get_tmds_output); > + > +/** > + * drm_dp_dual_mode_set_tmds_output - Enable/disable TMDS output buffers in the DP dual mode adaptor > + * type: DP dual mode adaptor type > + * adapter: I2C adapter for the DDC bus > + * enable: enable (as opposed to disable) the TMDS output buffers > + * > + * Set the state of the TMDS output buffers in the adaptor. For > + * type2 this is set via the DP_DUAL_MODE_TMDS_OEN register. As > + * some type 1 adaptors have problems with registers (see comments > + * in drm_dp_dual_mode_detect()) we avoid touching the register, > + * making this function a no-op on type 1 adaptors. > + * > + * Returns: > + * 0 on success, negative error code on failure > + */ > +int drm_dp_dual_mode_set_tmds_output(enum drm_dp_dual_mode_type type, > + struct i2c_adapter *adapter, bool enable) > +{ > + uint8_t tmds_oen = enable ? 0 : DP_DUAL_MODE_TMDS_DISABLE; > + ssize_t ret; > + > + if (type < DRM_DP_DUAL_MODE_TYPE2_DVI) > + return 0; > + > + ret = drm_dp_dual_mode_write(adapter, DP_DUAL_MODE_TMDS_OEN, > + &tmds_oen, sizeof(tmds_oen)); > + if (ret) > + return ret; > + > + return 0; > +} > +EXPORT_SYMBOL(drm_dp_dual_mode_set_tmds_output); > + > +/** > + * drm_dp_get_dual_mode_type_name - Get the name of the DP dual mode adaptor type as a string > + * type: DP dual mode adaptor type > + * > + * Returns: > + * String representation of the DP dual mode adaptor type > + */ > +const char *drm_dp_get_dual_mode_type_name(enum drm_dp_dual_mode_type type) > +{ > + switch (type) { > + case DRM_DP_DUAL_MODE_NONE: > + return "none"; > + case DRM_DP_DUAL_MODE_TYPE1_DVI: > + return "type 1 DVI"; > + case DRM_DP_DUAL_MODE_TYPE1_HDMI: > + return "type 1 HDMI"; > + case DRM_DP_DUAL_MODE_TYPE2_DVI: > + return "type 2 DVI"; > + case DRM_DP_DUAL_MODE_TYPE2_HDMI: > + return "type 2 HDMI"; > + default: > + WARN_ON(type != DRM_DP_DUAL_MODE_UNKNOWN); > + return "unknown"; > + } > +} > +EXPORT_SYMBOL(drm_dp_get_dual_mode_type_name); > diff --git a/include/drm/drm_dp_dual_mode_helper.h b/include/drm/drm_dp_dual_mode_helper.h > new file mode 100644 > index 000000000000..b4603b9fc03d > --- /dev/null > +++ b/include/drm/drm_dp_dual_mode_helper.h > @@ -0,0 +1,83 @@ > +/* > + * Copyright © 2016 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 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 COPYRIGHT HOLDER(S) OR AUTHOR(S) 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. > + */ > + > +#ifndef DRM_DP_DUAL_MODE_HELPER_H > +#define DRM_DP_DUAL_MODE_HELPER_H > + > +#include <linux/types.h> > + > +/* > + * Optional for type 1 DVI adaptors > + * Mandatory for type 1 HDMI and type 2 adators > + */ > +#define DP_DUAL_MODE_HDMI_ID 0x00 /* 00-0f */ > +#define DP_DUAL_MODE_HDMI_ID_LEN 16 > +/* > + * Optional for type 1 adaptors > + * Mandatory for type 2 adators > + */ > +#define DP_DUAL_MODE_ADAPTOR_ID 0x10 > +#define DP_DUAL_MODE_REV_MASK 0x07 > +#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_IEEE_OUI 0x11 /* 11-13*/ > +#define DP_DUAL_IEEE_OUI_LEN 3 > +#define DP_DUAL_DEVICE_ID 0x14 /* 14-19 */ > +#define DP_DUAL_DEVICE_ID_LEN 6 > +#define DP_DUAL_MODE_HARDWARE_REV 0x1a > +#define DP_DUAL_MODE_FIRMWARE_MAJOR_REV 0x1b > +#define DP_DUAL_MODE_FIRMWARE_MINOR_REV 0x1c > +#define DP_DUAL_MODE_MAX_TMDS_CLOCK 0x1d > +#define DP_DUAL_MODE_I2C_SPEED_CAP 0x1e > +#define DP_DUAL_MODE_TMDS_OEN 0x20 > +#define DP_DUAL_MODE_TMDS_DISABLE 0x01 > +#define DP_DUAL_MODE_HDMI_PIN_CTRL 0x21 > +#define DP_DUAL_MODE_CEC_ENABLE 0x01 > +#define DP_DUAL_MODE_I2C_SPEED_CTRL 0x22 > + > +struct i2c_adapter; > + > +ssize_t drm_dp_dual_mode_read(struct i2c_adapter *adapter, > + u8 offset, void *buffer, size_t size); > +ssize_t drm_dp_dual_mode_write(struct i2c_adapter *adapter, > + u8 offset, const void *buffer, size_t size); > + > +enum drm_dp_dual_mode_type { > + DRM_DP_DUAL_MODE_NONE, > + DRM_DP_DUAL_MODE_UNKNOWN, > + DRM_DP_DUAL_MODE_TYPE1_DVI, > + DRM_DP_DUAL_MODE_TYPE1_HDMI, > + DRM_DP_DUAL_MODE_TYPE2_DVI, > + DRM_DP_DUAL_MODE_TYPE2_HDMI, > +}; > + > +enum drm_dp_dual_mode_type drm_dp_dual_mode_detect(struct i2c_adapter *adapter); > +int drm_dp_dual_mode_max_tmds_clock(enum drm_dp_dual_mode_type type, > + struct i2c_adapter *adapter); > +int drm_dp_dual_mode_get_tmds_output(enum drm_dp_dual_mode_type type, > + struct i2c_adapter *adapter, bool *enabled); > +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); > + > +#endif -- Jani Nikula, Intel Open Source Technology Center -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html