Re: [PATCH v3 3/7] drm/bridge: ti-sn65dsi86: Implement AUX channel

[spanda@codeaurora.org]

On 2018-08-14 03:00, Sean Paul wrote:
> From: Sean Paul <seanpaul@chromium.org>
> 
> This was hand-rolled in the first version, and will surely be useful as
> we expand the driver to support more varied use cases.
> 
> Changes in v2:
> - Change subject prefix s/panel/bridge/
> - Downgrade warning in poll function to error message
> - Fix DP_EDP_CONFIGURATION_SET write value (Sandeep)
> - Mask upper 8 bits of msg->address (Sandeep)
> - Check aux cmd status for errors after completing the send (Sandeep)
> - Remove length check since it's covered in the aux status
> - Flip the READ check in transfer to WRITE check + early exit
> Changes in v3:
> - Added to the set
> - Wrapped (x) in WDATA/RDATA #defines
> - Replace readx_poll* with regmap_read_poll*
> 
> Cc: Sandeep Panda <spanda@codeaurora.org>
> Signed-off-by: Sean Paul <seanpaul@chromium.org>
> ---
>  drivers/gpu/drm/bridge/ti-sn65dsi86.c | 103 ++++++++++++++++++++++++--
>  1 file changed, 95 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> index 587d4e4f5674c..501f4a81ea5ab 100644
> --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> @@ -7,12 +7,14 @@
>  #include <drm/drm_atomic.h>
>  #include <drm/drm_atomic_helper.h>
>  #include <drm/drm_crtc_helper.h>
> +#include <drm/drm_dp_helper.h>
>  #include <drm/drm_mipi_dsi.h>
>  #include <drm/drm_of.h>
>  #include <drm/drm_panel.h>
>  #include <linux/clk.h>
>  #include <linux/gpio/consumer.h>
>  #include <linux/i2c.h>
> +#include <linux/iopoll.h>
>  #include <linux/of_graph.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/regmap.h>
> @@ -46,7 +48,7 @@
>  #define SN_DATA_FORMAT_REG			0x5B
>  #define SN_HPD_DISABLE_REG			0x5C
>  #define  HPD_DISABLE				BIT(0)
> -#define SN_AUX_WDATA0_REG			0x64
> +#define SN_AUX_WDATA_REG(x)			(0x64 + (x))
>  #define SN_AUX_ADDR_19_16_REG			0x74
>  #define SN_AUX_ADDR_15_8_REG			0x75
>  #define SN_AUX_ADDR_7_0_REG			0x76
> @@ -54,6 +56,7 @@
>  #define SN_AUX_CMD_REG				0x78
>  #define  AUX_CMD_SEND				BIT(1)
>  #define  AUX_CMD_REQ(x)				((x) << 4)
> +#define SN_AUX_RDATA_REG(x)			(0x79 + (x))
>  #define SN_SSC_CONFIG_REG			0x93
>  #define  DP_NUM_LANES_MASK			GENMASK(5, 4)
>  #define  DP_NUM_LANES(x)			((x) << 4)
> @@ -63,6 +66,10 @@
>  #define SN_ML_TX_MODE_REG			0x96
>  #define  ML_TX_MAIN_LINK_OFF			0
>  #define  ML_TX_NORMAL_MODE			BIT(0)
> +#define SN_AUX_CMD_STATUS_REG			0xF4
> +#define  AUX_IRQ_STATUS_AUX_RPLY_TOUT		BIT(3)
> +#define  AUX_IRQ_STATUS_AUX_SHORT		BIT(5)
> +#define  AUX_IRQ_STATUS_NAT_I2C_FAIL		BIT(6)
> 
>  #define MIN_DSI_CLK_FREQ_MHZ	40
> 
> @@ -70,11 +77,15 @@
>  #define DP_CLK_FUDGE_NUM	10
>  #define DP_CLK_FUDGE_DEN	8
> 
> +/* Matches DP_AUX_MAX_PAYLOAD_BYTES (for now) */
> +#define SN_AUX_MAX_PAYLOAD_BYTES	16
> +
>  #define SN_REGULATOR_SUPPLY_NUM		4
> 
>  struct ti_sn_bridge {
>  	struct device			*dev;
>  	struct regmap			*regmap;
> +	struct drm_dp_aux		aux;
>  	struct drm_bridge		bridge;
>  	struct drm_connector		connector;
>  	struct device_node		*host_node;
> @@ -471,13 +482,8 @@ static void ti_sn_bridge_enable(struct drm_bridge 
> *bridge)
>  	 * authentication method. We need to enable this method in the eDP 
> panel
>  	 * at DisplayPort address 0x0010A prior to link training.
>  	 */
> -	regmap_write(pdata->regmap, SN_AUX_WDATA0_REG, 0x01);
> -	regmap_write(pdata->regmap, SN_AUX_ADDR_19_16_REG, 0x00);
> -	regmap_write(pdata->regmap, SN_AUX_ADDR_15_8_REG, 0x01);
> -	regmap_write(pdata->regmap, SN_AUX_ADDR_7_0_REG, 0x0A);
> -	regmap_write(pdata->regmap, SN_AUX_LENGTH_REG, 0x01);
> -	regmap_write(pdata->regmap, SN_AUX_CMD_REG, 0x81);
> -	usleep_range(10000, 10500); /* 10ms delay recommended by spec */
> +	drm_dp_dpcd_writeb(&pdata->aux, DP_EDP_CONFIGURATION_SET,
> +			   DP_ALTERNATE_SCRAMBLER_RESET_ENABLE);
> 
>  	/* Semi auto link training mode */
>  	regmap_write(pdata->regmap, SN_ML_TX_MODE_REG, 0x0A);
> @@ -525,6 +531,82 @@ static const struct drm_bridge_funcs 
> ti_sn_bridge_funcs = {
>  	.post_disable = ti_sn_bridge_post_disable,
>  };
> 
> +static struct ti_sn_bridge *aux_to_ti_sn_bridge(struct drm_dp_aux 
> *aux)
> +{
> +	return container_of(aux, struct ti_sn_bridge, aux);
> +}
> +
> +static ssize_t ti_sn_aux_transfer(struct drm_dp_aux *aux,
> +				  struct drm_dp_aux_msg *msg)
> +{
> +	struct ti_sn_bridge *pdata = aux_to_ti_sn_bridge(aux);
> +	u32 request = msg->request & ~DP_AUX_I2C_MOT;
> +	u32 request_val = AUX_CMD_REQ(msg->request);
> +	u8 *buf = (u8 *)msg->buffer;
> +	unsigned int val;
> +	int ret, i;
> +
> +	if (msg->size > SN_AUX_MAX_PAYLOAD_BYTES)
> +		return -EINVAL;
> +
> +	switch (request) {
> +	case DP_AUX_NATIVE_WRITE:
> +	case DP_AUX_I2C_WRITE:
> +	case DP_AUX_NATIVE_READ:
> +	case DP_AUX_I2C_READ:
> +		regmap_write(pdata->regmap, SN_AUX_CMD_REG, request_val);
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	regmap_write(pdata->regmap, SN_AUX_ADDR_19_16_REG,
> +		     (msg->address >> 16) & 0xF);
> +	regmap_write(pdata->regmap, SN_AUX_ADDR_15_8_REG,
> +		     (msg->address >> 8) & 0xFF);
> +	regmap_write(pdata->regmap, SN_AUX_ADDR_7_0_REG, msg->address & 
> 0xFF);
> +
> +	regmap_write(pdata->regmap, SN_AUX_LENGTH_REG, msg->size);
> +
> +	if (request == DP_AUX_NATIVE_WRITE || request == DP_AUX_I2C_WRITE) {
> +		for (i = 0; i < msg->size; i++)
> +			regmap_write(pdata->regmap, SN_AUX_WDATA_REG(i),
> +				     buf[i]);
> +	}
> +
> +	regmap_write(pdata->regmap, SN_AUX_CMD_REG, request_val | 
> AUX_CMD_SEND);
> +
> +	ret = regmap_read_poll_timeout(pdata->regmap, SN_AUX_CMD_REG, val,
> +				       !(val & AUX_CMD_SEND), 200,
> +				       50 * 1000);
> +	if (ret)
> +		return ret;
> +
> +	ret = regmap_read(pdata->regmap, SN_AUX_CMD_STATUS_REG, &val);
> +	if (ret)
> +		return ret;
> +	else if ((val & AUX_IRQ_STATUS_NAT_I2C_FAIL)
> +		 || (val & AUX_IRQ_STATUS_AUX_RPLY_TOUT)
> +		 || (val & AUX_IRQ_STATUS_AUX_SHORT))
> +		return -ENXIO;
> +
> +	if (request == DP_AUX_NATIVE_WRITE || request == DP_AUX_I2C_WRITE)
> +		return msg->size;
> +
> +	for (i = 0; i < msg->size; i++) {
> +		unsigned int val;
> +		ret = regmap_read(pdata->regmap, SN_AUX_RDATA_REG(i),
> +				  &val);
> +		if (ret)
> +			return ret;
> +
> +		WARN_ON(val & ~0xFF);
> +		buf[i] = (u8)(val & 0xFF);
> +	}
> +
> +	return msg->size;
> +}
> +
>  static int ti_sn_bridge_parse_dsi_host(struct ti_sn_bridge *pdata)
>  {
>  	struct device_node *np = pdata->dev->of_node;
> @@ -604,6 +686,11 @@ static int ti_sn_bridge_probe(struct i2c_client 
> *client,
> 
>  	i2c_set_clientdata(client, pdata);
> 
> +	pdata->aux.name = "ti-sn65dsi86-aux";
> +	pdata->aux.dev = pdata->dev;
> +	pdata->aux.transfer = ti_sn_aux_transfer;
> +	drm_dp_aux_register(&pdata->aux);
> +
>  	pdata->bridge.funcs = &ti_sn_bridge_funcs;
>  	pdata->bridge.of_node = client->dev.of_node;
Reviewed-by: Sandeep Panda <spanda@codeaurora.org>
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