The driver knows exactly which version of the chip is present since
the vid/pid is used to enforce a compatibility. Given that some
devices like IT66121 has potentially been replaced with IT66122 mid
production for many platforms, it makes no sense to use the vid/pid as
an enforcement for compatibility. Instead, let us detect the ID of the
actual chip in use by matching the corresponding vid/pid.
This also allows for some future compatibility to be checked only
against a restricted set of vid/pid.
While at this, fix up a bit of formatting errors reported by
checkpatch warning, and since the ctx info just requires the id, drop
storing the entire chip_info pointer.
Signed-off-by: Nishanth Menon <nm@ti.com>
---
Changes in V3:
* Converted the patch to lookup ID based on vid/pid match rather than
enforcing vid/pid match per compatible.
* Squashed a formating fix for pre-existing checkpatch --strict warning
V2: https://lore.kernel.org/all/20250813204106.580141-3-nm@ti.com/
drivers/gpu/drm/bridge/ite-it66121.c | 53 ++++++++++++++--------------
1 file changed, 27 insertions(+), 26 deletions(-)
diff --git a/drivers/gpu/drm/bridge/ite-it66121.c b/drivers/gpu/drm/bridge/ite-it66121.c
index 9b8ed2fae2f4..5ac9631bcd9a 100644
--- a/drivers/gpu/drm/bridge/ite-it66121.c
+++ b/drivers/gpu/drm/bridge/ite-it66121.c
@@ -312,7 +312,7 @@ struct it66121_ctx {
u8 swl;
bool auto_cts;
} audio;
- const struct it66121_chip_info *info;
+ enum chip_id id;
};
static const struct regmap_range_cfg it66121_regmap_banks[] = {
@@ -402,7 +402,7 @@ static int it66121_configure_afe(struct it66121_ctx *ctx,
if (ret)
return ret;
- if (ctx->info->id == ID_IT66121) {
+ if (ctx->id == ID_IT66121) {
ret = regmap_write_bits(ctx->regmap, IT66121_AFE_IP_REG,
IT66121_AFE_IP_EC1, 0);
if (ret)
@@ -428,7 +428,7 @@ static int it66121_configure_afe(struct it66121_ctx *ctx,
if (ret)
return ret;
- if (ctx->info->id == ID_IT66121) {
+ if (ctx->id == ID_IT66121) {
ret = regmap_write_bits(ctx->regmap, IT66121_AFE_IP_REG,
IT66121_AFE_IP_EC1,
IT66121_AFE_IP_EC1);
@@ -449,7 +449,7 @@ static int it66121_configure_afe(struct it66121_ctx *ctx,
if (ret)
return ret;
- if (ctx->info->id == ID_IT6610) {
+ if (ctx->id == ID_IT6610) {
ret = regmap_write_bits(ctx->regmap, IT66121_AFE_XP_REG,
IT6610_AFE_XP_BYPASS,
IT6610_AFE_XP_BYPASS);
@@ -599,7 +599,7 @@ static int it66121_bridge_attach(struct drm_bridge *bridge,
if (ret)
return ret;
- if (ctx->info->id == ID_IT66121) {
+ if (ctx->id == ID_IT66121) {
ret = regmap_write_bits(ctx->regmap, IT66121_CLK_BANK_REG,
IT66121_CLK_BANK_PWROFF_RCLK, 0);
if (ret)
@@ -748,7 +748,7 @@ static int it66121_bridge_check(struct drm_bridge *bridge,
{
struct it66121_ctx *ctx = container_of(bridge, struct it66121_ctx, bridge);
- if (ctx->info->id == ID_IT6610) {
+ if (ctx->id == ID_IT6610) {
/* The IT6610 only supports these settings */
bridge_state->input_bus_cfg.flags |= DRM_BUS_FLAG_DE_HIGH |
DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE;
@@ -802,7 +802,7 @@ void it66121_bridge_mode_set(struct drm_bridge *bridge,
if (regmap_write(ctx->regmap, IT66121_HDMI_MODE_REG, IT66121_HDMI_MODE_HDMI))
goto unlock;
- if (ctx->info->id == ID_IT66121 &&
+ if (ctx->id == ID_IT66121 &&
regmap_write_bits(ctx->regmap, IT66121_CLK_BANK_REG,
IT66121_CLK_BANK_PWROFF_TXCLK,
IT66121_CLK_BANK_PWROFF_TXCLK)) {
@@ -815,7 +815,7 @@ void it66121_bridge_mode_set(struct drm_bridge *bridge,
if (it66121_configure_afe(ctx, adjusted_mode))
goto unlock;
- if (ctx->info->id == ID_IT66121 &&
+ if (ctx->id == ID_IT66121 &&
regmap_write_bits(ctx->regmap, IT66121_CLK_BANK_REG,
IT66121_CLK_BANK_PWROFF_TXCLK, 0)) {
goto unlock;
@@ -1505,6 +1505,7 @@ static int it66121_probe(struct i2c_client *client)
int ret;
struct it66121_ctx *ctx;
struct device *dev = &client->dev;
+ const struct it66121_chip_info *chip_info;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
dev_err(dev, "I2C check functionality failed.\n");
@@ -1522,7 +1523,7 @@ static int it66121_probe(struct i2c_client *client)
ctx->dev = dev;
ctx->client = client;
- ctx->info = i2c_get_match_data(client);
+ chip_info = i2c_get_match_data(client);
of_property_read_u32(ep, "bus-width", &ctx->bus_width);
of_node_put(ep);
@@ -1568,11 +1569,17 @@ static int it66121_probe(struct i2c_client *client)
revision_id = FIELD_GET(IT66121_REVISION_MASK, device_ids[1]);
device_ids[1] &= IT66121_DEVICE_ID1_MASK;
- if ((vendor_ids[1] << 8 | vendor_ids[0]) != ctx->info->vid ||
- (device_ids[1] << 8 | device_ids[0]) != ctx->info->pid) {
- return -ENODEV;
+ for (; chip_info->vid; chip_info++) {
+ if ((vendor_ids[1] << 8 | vendor_ids[0]) == chip_info->vid &&
+ (device_ids[1] << 8 | device_ids[0]) == chip_info->pid) {
+ ctx->id = chip_info->id;
+ break;
+ }
}
+ if (!chip_info->vid)
+ return -ENODEV;
+
ctx->bridge.of_node = dev->of_node;
ctx->bridge.type = DRM_MODE_CONNECTOR_HDMIA;
ctx->bridge.ops = DRM_BRIDGE_OP_DETECT | DRM_BRIDGE_OP_EDID;
@@ -1606,28 +1613,22 @@ static void it66121_remove(struct i2c_client *client)
mutex_destroy(&ctx->lock);
}
-static const struct it66121_chip_info it66121_chip_info = {
- .id = ID_IT66121,
- .vid = 0x4954,
- .pid = 0x0612,
-};
-
-static const struct it66121_chip_info it6610_chip_info = {
- .id = ID_IT6610,
- .vid = 0xca00,
- .pid = 0x0611,
+static const struct it66121_chip_info it66xx_chip_info[] = {
+ {.id = ID_IT66121, .vid = 0x4954, .pid = 0x0612 },
+ {.id = ID_IT6610, .vid = 0xca00, .pid = 0x0611 },
+ { }
};
static const struct of_device_id it66121_dt_match[] = {
- { .compatible = "ite,it66121", &it66121_chip_info },
- { .compatible = "ite,it6610", &it6610_chip_info },
+ { .compatible = "ite,it66121", &it66xx_chip_info },
+ { .compatible = "ite,it6610", &it66xx_chip_info },
{ }
};
MODULE_DEVICE_TABLE(of, it66121_dt_match);
static const struct i2c_device_id it66121_id[] = {
- { "it66121", (kernel_ulong_t) &it66121_chip_info },
- { "it6610", (kernel_ulong_t) &it6610_chip_info },
+ { "it66121", (kernel_ulong_t)&it66xx_chip_info },
+ { "it6610", (kernel_ulong_t)&it66xx_chip_info },
{ }
};
MODULE_DEVICE_TABLE(i2c, it66121_id);
--
2.47.0On Thu, Aug 14, 2025 at 10:41:04PM -0500, Nishanth Menon wrote:
> The driver knows exactly which version of the chip is present since
> the vid/pid is used to enforce a compatibility. Given that some
> devices like IT66121 has potentially been replaced with IT66122 mid
> production for many platforms, it makes no sense to use the vid/pid as
> an enforcement for compatibility. Instead, let us detect the ID of the
> actual chip in use by matching the corresponding vid/pid.
>
> This also allows for some future compatibility to be checked only
> against a restricted set of vid/pid.
>
> While at this, fix up a bit of formatting errors reported by
> checkpatch warning, and since the ctx info just requires the id, drop
> storing the entire chip_info pointer.
Separate commit, please. Don't mix unrelated changes into a single
patch. "While at it" usually means that it should be a separate patch.
>
> Signed-off-by: Nishanth Menon <nm@ti.com>
> ---
> Changes in V3:
> * Converted the patch to lookup ID based on vid/pid match rather than
> enforcing vid/pid match per compatible.
> * Squashed a formating fix for pre-existing checkpatch --strict warning
>
> V2: https://lore.kernel.org/all/20250813204106.580141-3-nm@ti.com/
>
> drivers/gpu/drm/bridge/ite-it66121.c | 53 ++++++++++++++--------------
> 1 file changed, 27 insertions(+), 26 deletions(-)
>
> @@ -1606,28 +1613,22 @@ static void it66121_remove(struct i2c_client *client)
> mutex_destroy(&ctx->lock);
> }
>
> -static const struct it66121_chip_info it66121_chip_info = {
> - .id = ID_IT66121,
> - .vid = 0x4954,
> - .pid = 0x0612,
> -};
> -
> -static const struct it66121_chip_info it6610_chip_info = {
> - .id = ID_IT6610,
> - .vid = 0xca00,
> - .pid = 0x0611,
> +static const struct it66121_chip_info it66xx_chip_info[] = {
> + {.id = ID_IT66121, .vid = 0x4954, .pid = 0x0612 },
> + {.id = ID_IT6610, .vid = 0xca00, .pid = 0x0611 },
> + { }
> };
>
> static const struct of_device_id it66121_dt_match[] = {
> - { .compatible = "ite,it66121", &it66121_chip_info },
> - { .compatible = "ite,it6610", &it6610_chip_info },
> + { .compatible = "ite,it66121", &it66xx_chip_info },
> + { .compatible = "ite,it6610", &it66xx_chip_info },
Other than dropping the match data completely, please keep arrays
sorted.
> { }
> };
> MODULE_DEVICE_TABLE(of, it66121_dt_match);
>
> static const struct i2c_device_id it66121_id[] = {
> - { "it66121", (kernel_ulong_t) &it66121_chip_info },
> - { "it6610", (kernel_ulong_t) &it6610_chip_info },
> + { "it66121", (kernel_ulong_t)&it66xx_chip_info },
> + { "it6610", (kernel_ulong_t)&it66xx_chip_info },
> { }
> };
> MODULE_DEVICE_TABLE(i2c, it66121_id);
> --
> 2.47.0
>
--
With best wishes
Dmitry
On 8/14/25 10:41 PM, Nishanth Menon wrote:
> The driver knows exactly which version of the chip is present since
> the vid/pid is used to enforce a compatibility. Given that some
> devices like IT66121 has potentially been replaced with IT66122 mid
> production for many platforms, it makes no sense to use the vid/pid as
> an enforcement for compatibility. Instead, let us detect the ID of the
> actual chip in use by matching the corresponding vid/pid.
>
> This also allows for some future compatibility to be checked only
> against a restricted set of vid/pid.
>
> While at this, fix up a bit of formatting errors reported by
> checkpatch warning, and since the ctx info just requires the id, drop
> storing the entire chip_info pointer.
>
> Signed-off-by: Nishanth Menon <nm@ti.com>
> ---
> Changes in V3:
> * Converted the patch to lookup ID based on vid/pid match rather than
> enforcing vid/pid match per compatible.
> * Squashed a formating fix for pre-existing checkpatch --strict warning
>
> V2: https://lore.kernel.org/all/20250813204106.580141-3-nm@ti.com/
>
> drivers/gpu/drm/bridge/ite-it66121.c | 53 ++++++++++++++--------------
> 1 file changed, 27 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/ite-it66121.c b/drivers/gpu/drm/bridge/ite-it66121.c
> index 9b8ed2fae2f4..5ac9631bcd9a 100644
> --- a/drivers/gpu/drm/bridge/ite-it66121.c
> +++ b/drivers/gpu/drm/bridge/ite-it66121.c
> @@ -312,7 +312,7 @@ struct it66121_ctx {
> u8 swl;
> bool auto_cts;
> } audio;
> - const struct it66121_chip_info *info;
> + enum chip_id id;
> };
>
> static const struct regmap_range_cfg it66121_regmap_banks[] = {
> @@ -402,7 +402,7 @@ static int it66121_configure_afe(struct it66121_ctx *ctx,
> if (ret)
> return ret;
>
> - if (ctx->info->id == ID_IT66121) {
> + if (ctx->id == ID_IT66121) {
> ret = regmap_write_bits(ctx->regmap, IT66121_AFE_IP_REG,
> IT66121_AFE_IP_EC1, 0);
> if (ret)
> @@ -428,7 +428,7 @@ static int it66121_configure_afe(struct it66121_ctx *ctx,
> if (ret)
> return ret;
>
> - if (ctx->info->id == ID_IT66121) {
> + if (ctx->id == ID_IT66121) {
> ret = regmap_write_bits(ctx->regmap, IT66121_AFE_IP_REG,
> IT66121_AFE_IP_EC1,
> IT66121_AFE_IP_EC1);
> @@ -449,7 +449,7 @@ static int it66121_configure_afe(struct it66121_ctx *ctx,
> if (ret)
> return ret;
>
> - if (ctx->info->id == ID_IT6610) {
> + if (ctx->id == ID_IT6610) {
> ret = regmap_write_bits(ctx->regmap, IT66121_AFE_XP_REG,
> IT6610_AFE_XP_BYPASS,
> IT6610_AFE_XP_BYPASS);
> @@ -599,7 +599,7 @@ static int it66121_bridge_attach(struct drm_bridge *bridge,
> if (ret)
> return ret;
>
> - if (ctx->info->id == ID_IT66121) {
> + if (ctx->id == ID_IT66121) {
> ret = regmap_write_bits(ctx->regmap, IT66121_CLK_BANK_REG,
> IT66121_CLK_BANK_PWROFF_RCLK, 0);
> if (ret)
> @@ -748,7 +748,7 @@ static int it66121_bridge_check(struct drm_bridge *bridge,
> {
> struct it66121_ctx *ctx = container_of(bridge, struct it66121_ctx, bridge);
>
> - if (ctx->info->id == ID_IT6610) {
> + if (ctx->id == ID_IT6610) {
> /* The IT6610 only supports these settings */
> bridge_state->input_bus_cfg.flags |= DRM_BUS_FLAG_DE_HIGH |
> DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE;
> @@ -802,7 +802,7 @@ void it66121_bridge_mode_set(struct drm_bridge *bridge,
> if (regmap_write(ctx->regmap, IT66121_HDMI_MODE_REG, IT66121_HDMI_MODE_HDMI))
> goto unlock;
>
> - if (ctx->info->id == ID_IT66121 &&
> + if (ctx->id == ID_IT66121 &&
> regmap_write_bits(ctx->regmap, IT66121_CLK_BANK_REG,
> IT66121_CLK_BANK_PWROFF_TXCLK,
> IT66121_CLK_BANK_PWROFF_TXCLK)) {
> @@ -815,7 +815,7 @@ void it66121_bridge_mode_set(struct drm_bridge *bridge,
> if (it66121_configure_afe(ctx, adjusted_mode))
> goto unlock;
>
> - if (ctx->info->id == ID_IT66121 &&
> + if (ctx->id == ID_IT66121 &&
> regmap_write_bits(ctx->regmap, IT66121_CLK_BANK_REG,
> IT66121_CLK_BANK_PWROFF_TXCLK, 0)) {
> goto unlock;
> @@ -1505,6 +1505,7 @@ static int it66121_probe(struct i2c_client *client)
> int ret;
> struct it66121_ctx *ctx;
> struct device *dev = &client->dev;
> + const struct it66121_chip_info *chip_info;
>
> if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
> dev_err(dev, "I2C check functionality failed.\n");
> @@ -1522,7 +1523,7 @@ static int it66121_probe(struct i2c_client *client)
>
> ctx->dev = dev;
> ctx->client = client;
> - ctx->info = i2c_get_match_data(client);
> + chip_info = i2c_get_match_data(client);
>
> of_property_read_u32(ep, "bus-width", &ctx->bus_width);
> of_node_put(ep);
> @@ -1568,11 +1569,17 @@ static int it66121_probe(struct i2c_client *client)
> revision_id = FIELD_GET(IT66121_REVISION_MASK, device_ids[1]);
> device_ids[1] &= IT66121_DEVICE_ID1_MASK;
>
> - if ((vendor_ids[1] << 8 | vendor_ids[0]) != ctx->info->vid ||
> - (device_ids[1] << 8 | device_ids[0]) != ctx->info->pid) {
> - return -ENODEV;
> + for (; chip_info->vid; chip_info++) {
> + if ((vendor_ids[1] << 8 | vendor_ids[0]) == chip_info->vid &&
> + (device_ids[1] << 8 | device_ids[0]) == chip_info->pid) {
> + ctx->id = chip_info->id;
> + break;
> + }
> }
>
> + if (!chip_info->vid)
> + return -ENODEV;
> +
> ctx->bridge.of_node = dev->of_node;
> ctx->bridge.type = DRM_MODE_CONNECTOR_HDMIA;
> ctx->bridge.ops = DRM_BRIDGE_OP_DETECT | DRM_BRIDGE_OP_EDID;
> @@ -1606,28 +1613,22 @@ static void it66121_remove(struct i2c_client *client)
> mutex_destroy(&ctx->lock);
> }
>
> -static const struct it66121_chip_info it66121_chip_info = {
> - .id = ID_IT66121,
> - .vid = 0x4954,
> - .pid = 0x0612,
> -};
> -
> -static const struct it66121_chip_info it6610_chip_info = {
> - .id = ID_IT6610,
> - .vid = 0xca00,
> - .pid = 0x0611,
> +static const struct it66121_chip_info it66xx_chip_info[] = {
> + {.id = ID_IT66121, .vid = 0x4954, .pid = 0x0612 },
> + {.id = ID_IT6610, .vid = 0xca00, .pid = 0x0611 },
> + { }
> };
>
> static const struct of_device_id it66121_dt_match[] = {
> - { .compatible = "ite,it66121", &it66121_chip_info },
> - { .compatible = "ite,it6610", &it6610_chip_info },
> + { .compatible = "ite,it66121", &it66xx_chip_info },
> + { .compatible = "ite,it6610", &it66xx_chip_info },
If you will pass in the same data to all devices, just don't pass
anything. Move the it66121_dt_match table up above probe, and just
use it, no need for fetching it from i2c_get_match_data().
That can also be done later too, so not a blocker here,
Reviewed-by: Andrew Davis <afd@ti.com>
> { }
> };
> MODULE_DEVICE_TABLE(of, it66121_dt_match);
>
> static const struct i2c_device_id it66121_id[] = {
> - { "it66121", (kernel_ulong_t) &it66121_chip_info },
> - { "it6610", (kernel_ulong_t) &it6610_chip_info },
> + { "it66121", (kernel_ulong_t)&it66xx_chip_info },
> + { "it6610", (kernel_ulong_t)&it66xx_chip_info },
> { }
> };
> MODULE_DEVICE_TABLE(i2c, it66121_id);
On 08:52-20250815, Andrew Davis wrote:
> > This also allows for some future compatibility to be checked only
> > against a restricted set of vid/pid.
^^ See below
> > static const struct of_device_id it66121_dt_match[] = {
> > - { .compatible = "ite,it66121", &it66121_chip_info },
> > - { .compatible = "ite,it6610", &it6610_chip_info },
> > + { .compatible = "ite,it66121", &it66xx_chip_info },
> > + { .compatible = "ite,it6610", &it66xx_chip_info },
>
> If you will pass in the same data to all devices, just don't pass
> anything. Move the it66121_dt_match table up above probe, and just
> use it, no need for fetching it from i2c_get_match_data().
(rationale in commit messsage)
Yeah, I was going to do that, but this vendor has a bunch of devices and
I am not able to see all possible combinations.. so was thinking that
maybe some combination device will need different checks with a limited
vid/pid list.. just lack of public documentation makes me a bit
paranoid.
I am not tied to this that hard (it was a "meh"), so if folks feel this
can be thrown out, can respin.
--
Regards,
Nishanth Menon
Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3 1A34 DDB5 849D 1736 249D
https://ti.com/opensource
© 2016 - 2025 Red Hat, Inc.