Commit 88537ddb authored by Linus Walleij's avatar Linus Walleij
Browse files

drm/mcde: Fix DSI transfers 



There were bugs in the DSI transfer (read and write) function
as it was only tested with displays ever needing a single byte
to be written. Fixed it up and tested so we can now write
messages of up to 16 bytes and read up to 4 bytes from the
display.

Tested with a Sony ACX424AKP display: this display now self-
identifies and can control backlight in command mode.

Reported-by: default avatarkbuild test robot <lkp@intel.com>
Fixes: 5fc537bf ("drm/mcde: Add new driver for ST-Ericsson MCDE")
Reviewed-by: default avatarStephan Gerhold <stephan@gerhold.net>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190903170804.17053-1-linus.walleij@linaro.org
parent 45d0dbd1

drivers/gpu/drm/mcde/mcde_dsi.c

+47 −23
Original line number Diff line number Diff line
@@ -178,22 +178,26 @@ static ssize_t mcde_dsi_host_transfer(struct mipi_dsi_host *host, 
	const u32 loop_delay_us = 10; /* us */

	const u8 *tx = msg->tx_buf;

	u32 loop_counter;

	size_t txlen;

	size_t txlen = msg->tx_len;

	size_t rxlen = msg->rx_len;

	u32 val;

	int ret;

	int i;



	txlen = msg->tx_len;

	if (txlen > 12) {

	if (txlen > 16) {

		dev_err(d->dev,

			"dunno how to write more than 12 bytes yet\n");

			"dunno how to write more than 16 bytes yet\n");

		return -EIO;

	}

	if (rxlen > 4) {

		dev_err(d->dev,

			"dunno how to read more than 4 bytes yet\n");

		return -EIO;

	}



	dev_dbg(d->dev,

		"message to channel %d, %zd bytes",

		msg->channel,

		txlen);

		"message to channel %d, write %zd bytes read %zd bytes\n",

		msg->channel, txlen, rxlen);



	/* Command "nature" */

	if (MCDE_DSI_HOST_IS_READ(msg->type))
@@ -210,9 +214,7 @@ static ssize_t mcde_dsi_host_transfer(struct mipi_dsi_host *host, 
	if (mipi_dsi_packet_format_is_long(msg->type))

		val |= DSI_DIRECT_CMD_MAIN_SETTINGS_CMD_LONGNOTSHORT;

	val |= 0 << DSI_DIRECT_CMD_MAIN_SETTINGS_CMD_ID_SHIFT;

	/* Add one to the length for the MIPI DCS command */

	val |= txlen

		<< DSI_DIRECT_CMD_MAIN_SETTINGS_CMD_SIZE_SHIFT;

	val |= txlen << DSI_DIRECT_CMD_MAIN_SETTINGS_CMD_SIZE_SHIFT;

	val |= DSI_DIRECT_CMD_MAIN_SETTINGS_CMD_LP_EN;

	val |= msg->type << DSI_DIRECT_CMD_MAIN_SETTINGS_CMD_HEAD_SHIFT;

	writel(val, d->regs + DSI_DIRECT_CMD_MAIN_SETTINGS);
@@ -249,6 +251,19 @@ static ssize_t mcde_dsi_host_transfer(struct mipi_dsi_host *host, 
	writel(1, d->regs + DSI_DIRECT_CMD_SEND);



	loop_counter = 1000 * 1000 / loop_delay_us;

	if (MCDE_DSI_HOST_IS_READ(msg->type)) {

		/* Read command */

		while (!(readl(d->regs + DSI_DIRECT_CMD_STS) &

			 (DSI_DIRECT_CMD_STS_READ_COMPLETED |

			  DSI_DIRECT_CMD_STS_READ_COMPLETED_WITH_ERR))

		       && --loop_counter)

			usleep_range(loop_delay_us, (loop_delay_us * 3) / 2);

		if (!loop_counter) {

			dev_err(d->dev, "DSI read timeout!\n");

			return -ETIME;

		}

	} else {

		/* Writing only */

		while (!(readl(d->regs + DSI_DIRECT_CMD_STS) &

			 DSI_DIRECT_CMD_STS_WRITE_COMPLETED)

		       && --loop_counter)
@@ -258,8 +273,14 @@ static ssize_t mcde_dsi_host_transfer(struct mipi_dsi_host *host, 
			dev_err(d->dev, "DSI write timeout!\n");

			return -ETIME;

		}

	}



	val = readl(d->regs + DSI_DIRECT_CMD_STS);

	if (val & DSI_DIRECT_CMD_STS_READ_COMPLETED_WITH_ERR) {

		dev_err(d->dev, "read completed with error\n");

		writel(1, d->regs + DSI_DIRECT_CMD_RD_INIT);

		return -EIO;

	}

	if (val & DSI_DIRECT_CMD_STS_ACKNOWLEDGE_WITH_ERR_RECEIVED) {

		val >>= DSI_DIRECT_CMD_STS_ACK_VAL_SHIFT;

		dev_err(d->dev, "error during transmission: %04x\n",
@@ -269,10 +290,7 @@ static ssize_t mcde_dsi_host_transfer(struct mipi_dsi_host *host, 


	if (!MCDE_DSI_HOST_IS_READ(msg->type)) {

		/* Return number of bytes written */

		if (mipi_dsi_packet_format_is_long(msg->type))

			ret = 4 + txlen;

		else

			ret = 4;

		ret = txlen;

	} else {

		/* OK this is a read command, get the response */

		u32 rdsz;
@@ -282,7 +300,13 @@ static ssize_t mcde_dsi_host_transfer(struct mipi_dsi_host *host, 
		rdsz = readl(d->regs + DSI_DIRECT_CMD_RD_PROPERTY);

		rdsz &= DSI_DIRECT_CMD_RD_PROPERTY_RD_SIZE_MASK;

		rddat = readl(d->regs + DSI_DIRECT_CMD_RDDAT);

		for (i = 0; i < 4 && i < rdsz; i++)

		if (rdsz < rxlen) {

			dev_err(d->dev, "read error, requested %zd got %d\n",

				rxlen, rdsz);

			return -EIO;

		}

		/* FIXME: read more than 4 bytes */

		for (i = 0; i < 4 && i < rxlen; i++)

			rx[i] = (rddat >> (i * 8)) & 0xff;

		ret = rdsz;

	}

CRA Git | Maintained and supported by SUSTech CRA and CCSE