[Intel-gfx] [PATCH 1/5] drm: Helper for LSPCON in drm_dp_dual_mode
Sharma, Shashank
shashank.sharma at intel.com
Tue May 31 10:52:08 UTC 2016
Thanks for the review, Ville.
My comments, inline.
Regards
Shashank
On 5/31/2016 3:22 PM, Ville Syrjälä wrote:
> On Tue, May 31, 2016 at 02:55:42PM +0530, Shashank Sharma wrote:
>> Signed-off-by: Shashank Sharma <shashank.sharma at intel.com>
>> ---
>> drivers/gpu/drm/drm_dp_dual_mode_helper.c | 85 +++++++++++++++++++++++++++++++
>> include/drm/drm_dp_dual_mode_helper.h | 29 +++++++++++
>> 2 files changed, 114 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..11cab25 100644
>> --- a/drivers/gpu/drm/drm_dp_dual_mode_helper.c
>> +++ b/drivers/gpu/drm/drm_dp_dual_mode_helper.c
>> @@ -148,6 +148,12 @@ 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 == 0xa8);
>
>
> I'd probably make this something like
>
> #define DP_DUAL_MODE_RESERVED_LSPCON 0x08
>
> return adaptor_id == (DP_DUAL_MODE_TYPE_TYPE2 |
> DP_DUAL_MODE_RESERVED_LSPCON |
> DP_DUAL_MODE_REV_TYPE2);
>
Thanks, this is a good suggestion, I will do so.
>
>> +}
>> +
>> /**
>> * drm_dp_dual_mode_detect - Identify the DP dual mode adaptor
>> * @adapter: I2C adapter for the DDC bus
>> @@ -203,6 +209,8 @@ 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 +372,80 @@ 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
>> + *
>> + * Returns:
>> + * Enum representing current mode of operation
>> + */
>> +enum drm_lspcon_mode
>> +drm_lspcon_get_current_mode(struct i2c_adapter *adapter)
>
> To match with drm_dp_dual_mode_get_tmds_output() this may want to
> return the error status, and return the actual mode via a function
> argument.
>
sure, can be done.
> As for the name drm_dp_dual_mode_get_lspcon_mode() and
> drm_dp_dual_mode_set_lspcon_mode() perhaps?
> Or drm_lspcon_get_mode()/drm_lspcon_set_mode() perhaps if we want to
> keep things shorter?
>
Yep, initially I made the same names as you suggested, but
drm_dp_dual_mode_get_lspcon_mode dint sound good to me :).
drm_lspcon_get/set_mode sounds good.
>> +{
>> + u8 data;
>> + int err = 0;
>
> I used 'ret' in the rest of the code. This is a bit inconsistent.
got it.
>
>> +
>> + /* Read Status: i2c over aux */
>> + err = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_LSPCON_CURRENT_MODE,
>> + (void *)&data, sizeof(data));
>
> Pointless cast.
>
good catch, this is unnecessary.
>> + if (err < 0) {
>
> if (ret) is what I've used elsewhere.
got it.
>
>> + DRM_ERROR("LSPCON read(0x80, 0x41) failed\n");
>
> I'm not sure we want and ERROR from a helper. I used DRM_DEBUG_KMS for
> the other error paths.
>
IMHO, This is a failure which needs notice, as it can point out to a HW
level problem, or a problem in LSPCON FW, so I will prefer to keep it as
error.
>> + return DRM_LSPCON_MODE_INVALID;
>> + }
>> +
>> + return data & DP_DUAL_MODE_LSPCON_MODE_MASK ?
>> + DRM_LSPCON_MODE_PCON : DRM_LSPCON_MODE_LS;
>> +}
>> +EXPORT_SYMBOL(drm_lspcon_get_current_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_change_mode(struct i2c_adapter *adapter,
>> + enum drm_lspcon_mode reqd_mode)
>> +{
>> + u8 data;
>> + int err;
>> + int time_out = 200;
>> +
>> + if (reqd_mode == DRM_LSPCON_MODE_LS)
>> + data = ~DP_DUAL_MODE_LSPCON_MODE_MASK;
>
> Is that really correct?
>
Oops, it was a blunder, but fortunately that register only bothers about
bit 0, and that's why it worked, I will fix this.
>> + else
>> + data = DP_DUAL_MODE_LSPCON_MODE_MASK;
>> +
>> + /* Change mode */
>> + err = drm_dp_dual_mode_write(adapter, DP_DUAL_MODE_LSPCON_MODE_CHANGE,
>> + &data, sizeof(data));
>> + if (err < 0) {
>> + DRM_ERROR("LSPCON mode change failed\n");
>> + return err;
>> + }
>> +
>> + /*
>> + * 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.
>> + */
>
> indent fail
OK.
>
>> + while (time_out) {
>> + if (reqd_mode != drm_lspcon_get_current_mode(adapter)) {
>> + mdelay(10);
>
> mdelay() is bad.
Do you think I should replace with some of the non-busy wait (like
msleep or so ?)
>
>> + time_out -= 10;
>> + } else {
>> + DRM_DEBUG_KMS("LSPCON mode changed to %s\n",
>> + reqd_mode == DRM_LSPCON_MODE_LS ? "LS" : "PCON");
>> + return 0;
>> + }
>> + }
>> +
>> + DRM_ERROR("LSPCON mode change timed out\n");
>> + return -EFAULT;
>
> EFAULT doens't seem like a sensible error value here. ETIMEDOUT I
> suppose seems like what we should return.
Sure.
>
>> +}
>> +EXPORT_SYMBOL(drm_lspcon_change_mode);
>> diff --git a/include/drm/drm_dp_dual_mode_helper.h b/include/drm/drm_dp_dual_mode_helper.h
>> index e8a9dfd..f335df5 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
>> @@ -54,6 +55,9 @@
>> #define DP_DUAL_MODE_HDMI_PIN_CTRL 0x21
>> #define DP_DUAL_MODE_CEC_ENABLE 0x01
>> #define DP_DUAL_MODE_I2C_SPEED_CTRL 0x22
>
> Maybe leave an empty line here to separate the standard regs from the
> vendor specific ones. Hmm. Actually the vendor register space is
> 0x30-0x3f, whereas 0x40+ is reserved. But anyway empty line would
> seem warranted.
>
Got it.
>> +#define DP_DUAL_MODE_LSPCON_MODE_CHANGE 0x40
>> +#define DP_DUAL_MODE_LSPCON_CURRENT_MODE 0x41
>> +#define DP_DUAL_MODE_LSPCON_MODE_MASK 0x1
>
> Please indent the bit defnition by one space to make it stand out from
> the reg defines a little.
>
Ok, the first two are registers only, I guess this is for
DP_DUAL_MODE_LSPCON_MODE_MASK. I will align it.
>> struct i2c_adapter;
>>
>> @@ -63,6 +67,20 @@ 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_invalid: No idea what's going on
>> +* @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,
>> +};
>
> If we change the _get_mode() thing to return the error status separately
> from the mode, we won't need the INVALID value.
>
Agree.
>> +
>> +/**
>> * 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 +88,7 @@ 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 +97,7 @@ 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 +109,13 @@ 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_dp_dual_mode_ioa_read(struct i2c_adapter *adapter, u8 *buffer,
>> + u8 offset, u8 no_of_bytes);
>> +int drm_dp_dual_mode_ioa_write(struct i2c_adapter *adapter, u8 *buffer,
>> + u8 offset, u8 no_of_bytes);
>> +int drm_dp_dual_mode_get_edid(void *data,
>> + u8 *buf, unsigned int block, size_t len);
>> +enum drm_lspcon_mode drm_lspcon_get_current_mode(struct i2c_adapter *adapter);
>> +int drm_lspcon_change_mode(struct i2c_adapter *adapter,
>> + enum drm_lspcon_mode reqd_mode);
>> #endif
>> --
>> 1.9.1
>
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