diff options
| author | Wolfram Sang <wsa+renesas@sang-engineering.com> | 2025-03-18 16:52:56 +0100 |
|---|---|---|
| committer | Douglas Anderson <dianders@chromium.org> | 2025-03-24 08:47:58 -0700 |
| commit | d69362f55fba92eb4cac10fe8da618de52b49bfc (patch) | |
| tree | 7467fbce8eaa969564780239ae9a7b5da20f5103 | |
| parent | 1d1f7b15cb9c11974cebfd39da51dc69b8cb31ff (diff) | |
drm/bridge: ti-sn65dsi86: Check bridge connection failure
Read out and check the ID registers, so we can bail out if I2C
communication does not work or if the device is unknown. Tested on a
Renesas GrayHawk board (R-Car V4M) by using a wrong I2C address and by
not enabling RuntimePM for the device.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20250318155549.19625-2-wsa+renesas@sang-engineering.com
| -rw-r--r-- | drivers/gpu/drm/bridge/ti-sn65dsi86.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c index c2bdc7e57ac7..f72675766e01 100644 --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c @@ -35,6 +35,7 @@ #include <drm/drm_print.h> #include <drm/drm_probe_helper.h> +#define SN_DEVICE_ID_REGS 0x00 /* up to 0x07 */ #define SN_DEVICE_REV_REG 0x08 #define SN_DPPLL_SRC_REG 0x0A #define DPPLL_CLK_SRC_DSICLK BIT(0) @@ -1898,6 +1899,7 @@ static int ti_sn65dsi86_probe(struct i2c_client *client) { struct device *dev = &client->dev; struct ti_sn65dsi86 *pdata; + u8 id_buf[8]; int ret; if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { @@ -1941,6 +1943,16 @@ static int ti_sn65dsi86_probe(struct i2c_client *client) if (ret) return ret; + pm_runtime_get_sync(dev); + ret = regmap_bulk_read(pdata->regmap, SN_DEVICE_ID_REGS, id_buf, ARRAY_SIZE(id_buf)); + pm_runtime_put_autosuspend(dev); + if (ret) + return dev_err_probe(dev, ret, "failed to read device id\n"); + + /* The ID string is stored backwards */ + if (strncmp(id_buf, "68ISD ", ARRAY_SIZE(id_buf))) + return dev_err_probe(dev, -EOPNOTSUPP, "unsupported device id\n"); + /* * Break ourselves up into a collection of aux devices. The only real * motiviation here is to solve the chicken-and-egg problem of probe |