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: kbuild test robot <lkp@xxxxxxxxx>
Fixes: 5fc537bfd000 ("drm/mcde: Add new driver for ST-Ericsson MCDE")
Reviewed-by: Stephan Gerhold <stephan@xxxxxxxxxxx>
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
---
ChangeLog v2->v3:
- Fix an error message to indicate reading error rather than
writing error.
- Use the local variable for underflow print.
- Collected Stephan's reviewed-by.
ChangeLog v1->v2:
- Fix a print modifier for dev_err() found by the build robot.
---
drivers/gpu/drm/mcde/mcde_dsi.c | 70 ++++++++++++++++++++++-----------
1 file changed, 47 insertions(+), 23 deletions(-)
diff --git a/drivers/gpu/drm/mcde/mcde_dsi.c b/drivers/gpu/drm/mcde/mcde_dsi.c
index 07f7090d08b3..cd261c266f35 100644
--- a/drivers/gpu/drm/mcde/mcde_dsi.c
+++ b/drivers/gpu/drm/mcde/mcde_dsi.c
@@ -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);
@@ -249,17 +251,36 @@ 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;
- while (!(readl(d->regs + DSI_DIRECT_CMD_STS) &
- DSI_DIRECT_CMD_STS_WRITE_COMPLETED)
- && --loop_counter)
- usleep_range(loop_delay_us, (loop_delay_us * 3) / 2);
-
- if (!loop_counter) {
- dev_err(d->dev, "DSI write timeout!\n");
- return -ETIME;
+ 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 write timeout!\n");
+ return -ETIME;
+ }
+ } else {
+ /* Writing only */
+ while (!(readl(d->regs + DSI_DIRECT_CMD_STS) &
+ DSI_DIRECT_CMD_STS_WRITE_COMPLETED)
+ && --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;
+ }
}
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 %zd\n",
+ msg->rx_len, rxlen);
+ return -EIO;
+ }
+ /* FIXME: read more than 4 bytes */
+ for (i = 0; i < 4 && i < rxlen; i++)
rx[i] = (rddat >> (i * 8)) & 0xff;
ret = rdsz;
}
--
2.21.0
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