[PATCH v6 2/2] drm/bridge: parade-ps8640: Add support for AUX channel
Philip Chen
philipchen at chromium.org
Tue Sep 21 18:06:17 UTC 2021
Implement the first version of AUX support, which will be useful as
we expand the driver to support varied use cases.
Reviewed-by: Sam Ravnborg <sam at ravnborg.org>
Signed-off-by: Philip Chen <philipchen at chromium.org>
---
Changes in v6:
- Error check the aux address is no greater than 20 bits
- Read RDATA into a u32 variable and then copy the byte to the u8 buf
- Fix a few nits from v5 review
Changes in v5:
- Add a couple of syntax fixes accidentally uncommited in v4
Changes in v4:
- Fix aux_transfer function:
- Replace dev_err with DRM_DEV_ERROR
- Reorg the bit manipulation around address/len/request registers
- Make SWAUX_STATUS_I2C_NACK fall through to SWAUX_STATUS_ACKM and
store the number of read bytes to `len` w/o returning immediately
Changes in v3:
- Verify with HW and thus remove WARNING from the patch description
- Fix the reg names to better match the manual
- Fix aux_transfer function:
- Fix the switch statement which handles aux request
- Write the original (unstripped) aux request code to the register
- Replace DRM_ERROR with dev_err
- Remove goto and just return ret
- Fix the switch statement which handles aux status
- When reading returned data, read from RDATA instead of WDATA
- Fix attach function:
- Call mipi_dsi_detach() when aux_register fails
Changes in v2:
- Handle the case where an AUX transaction has no payload
- Add a reg polling for p0.0x83 to confirm AUX cmd is issued and
read data is returned
- Replace regmap_noinc_read/write with looped regmap_read/write,
as regmap_noinc_read/write doesn't read one byte at a time unless
max_raw_read/write is set to 1.
- Register/Unregister the AUX device explicitly when the bridge is
attached/detached
- Remove the use of runtime PM
- Program AUX addr/cmd/len in a single regmap_bulk_write()
- Add newlines for DRM_ERROR messages
drivers/gpu/drm/bridge/parade-ps8640.c | 181 ++++++++++++++++++++++++-
1 file changed, 180 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c
index 18328e75bf90..56a206967e3d 100644
--- a/drivers/gpu/drm/bridge/parade-ps8640.c
+++ b/drivers/gpu/drm/bridge/parade-ps8640.c
@@ -13,11 +13,36 @@
#include <linux/regulator/consumer.h>
#include <drm/drm_bridge.h>
+#include <drm/drm_dp_helper.h>
#include <drm/drm_mipi_dsi.h>
#include <drm/drm_of.h>
#include <drm/drm_panel.h>
#include <drm/drm_print.h>
+#define PAGE0_AUXCH_CFG3 0x76
+#define AUXCH_CFG3_RESET 0xff
+#define PAGE0_SWAUX_ADDR_7_0 0x7d
+#define PAGE0_SWAUX_ADDR_15_8 0x7e
+#define PAGE0_SWAUX_ADDR_23_16 0x7f
+#define SWAUX_ADDR_MASK GENMASK(19, 0)
+#define PAGE0_SWAUX_LENGTH 0x80
+#define SWAUX_LENGTH_MASK GENMASK(3, 0)
+#define SWAUX_NO_PAYLOAD BIT(7)
+#define PAGE0_SWAUX_WDATA 0x81
+#define PAGE0_SWAUX_RDATA 0x82
+#define PAGE0_SWAUX_CTRL 0x83
+#define SWAUX_SEND BIT(0)
+#define PAGE0_SWAUX_STATUS 0x84
+#define SWAUX_M_MASK GENMASK(4, 0)
+#define SWAUX_STATUS_MASK GENMASK(7, 5)
+#define SWAUX_STATUS_NACK (0x1 << 5)
+#define SWAUX_STATUS_DEFER (0x2 << 5)
+#define SWAUX_STATUS_ACKM (0x3 << 5)
+#define SWAUX_STATUS_INVALID (0x4 << 5)
+#define SWAUX_STATUS_I2C_NACK (0x5 << 5)
+#define SWAUX_STATUS_I2C_DEFER (0x6 << 5)
+#define SWAUX_STATUS_TIMEOUT (0x7 << 5)
+
#define PAGE2_GPIO_H 0xa7
#define PS_GPIO9 BIT(1)
#define PAGE2_I2C_BYPASS 0xea
@@ -68,6 +93,7 @@ enum ps8640_vdo_control {
struct ps8640 {
struct drm_bridge bridge;
struct drm_bridge *panel_bridge;
+ struct drm_dp_aux aux;
struct mipi_dsi_device *dsi;
struct i2c_client *page[MAX_DEVS];
struct regmap *regmap[MAX_DEVS];
@@ -117,6 +143,137 @@ static inline struct ps8640 *bridge_to_ps8640(struct drm_bridge *e)
return container_of(e, struct ps8640, bridge);
}
+static inline struct ps8640 *aux_to_ps8640(struct drm_dp_aux *aux)
+{
+ return container_of(aux, struct ps8640, aux);
+}
+
+static ssize_t ps8640_aux_transfer(struct drm_dp_aux *aux,
+ struct drm_dp_aux_msg *msg)
+{
+ struct ps8640 *ps_bridge = aux_to_ps8640(aux);
+ struct regmap *map = ps_bridge->regmap[PAGE0_DP_CNTL];
+ struct device *dev = &ps_bridge->page[PAGE0_DP_CNTL]->dev;
+ unsigned int len = msg->size;
+ unsigned int data;
+ unsigned int base;
+ int ret;
+ u8 request = msg->request &
+ ~(DP_AUX_I2C_MOT | DP_AUX_I2C_WRITE_STATUS_UPDATE);
+ u8 *buf = msg->buffer;
+ u8 addr_len[PAGE0_SWAUX_LENGTH + 1 - PAGE0_SWAUX_ADDR_7_0];
+ u8 i;
+ bool is_native_aux = false;
+
+ if (len > DP_AUX_MAX_PAYLOAD_BYTES)
+ return -EINVAL;
+
+ if (msg->address & ~SWAUX_ADDR_MASK)
+ return -EINVAL;
+
+ switch (request) {
+ case DP_AUX_NATIVE_WRITE:
+ case DP_AUX_NATIVE_READ:
+ is_native_aux = true;
+ fallthrough;
+ case DP_AUX_I2C_WRITE:
+ case DP_AUX_I2C_READ:
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ ret = regmap_write(map, PAGE0_AUXCH_CFG3, AUXCH_CFG3_RESET);
+ if (ret) {
+ DRM_DEV_ERROR(dev, "failed to write PAGE0_AUXCH_CFG3: %d\n",
+ ret);
+ return ret;
+ }
+
+ /* Assume it's good */
+ msg->reply = 0;
+
+ base = PAGE0_SWAUX_ADDR_7_0;
+ addr_len[PAGE0_SWAUX_ADDR_7_0 - base] = msg->address;
+ addr_len[PAGE0_SWAUX_ADDR_15_8 - base] = msg->address >> 8;
+ addr_len[PAGE0_SWAUX_ADDR_23_16 - base] = (msg->address >> 16) |
+ (msg->request << 4);
+ addr_len[PAGE0_SWAUX_LENGTH - base] = (len == 0) ? SWAUX_NO_PAYLOAD :
+ ((len - 1) & SWAUX_LENGTH_MASK);
+
+ regmap_bulk_write(map, PAGE0_SWAUX_ADDR_7_0, addr_len,
+ ARRAY_SIZE(addr_len));
+
+ if (len && (request == DP_AUX_NATIVE_WRITE ||
+ request == DP_AUX_I2C_WRITE)) {
+ /* Write to the internal FIFO buffer */
+ for (i = 0; i < len; i++) {
+ ret = regmap_write(map, PAGE0_SWAUX_WDATA, buf[i]);
+ if (ret) {
+ DRM_DEV_ERROR(dev,
+ "failed to write WDATA: %d\n",
+ ret);
+ return ret;
+ }
+ }
+ }
+
+ regmap_write(map, PAGE0_SWAUX_CTRL, SWAUX_SEND);
+
+ /* Zero delay loop because i2c transactions are slow already */
+ regmap_read_poll_timeout(map, PAGE0_SWAUX_CTRL, data,
+ !(data & SWAUX_SEND), 0, 50 * 1000);
+
+ regmap_read(map, PAGE0_SWAUX_STATUS, &data);
+ if (ret) {
+ DRM_DEV_ERROR(dev, "failed to read PAGE0_SWAUX_STATUS: %d\n",
+ ret);
+ return ret;
+ }
+
+ switch (data & SWAUX_STATUS_MASK) {
+ /* Ignore the DEFER cases as they are already handled in hardware */
+ case SWAUX_STATUS_NACK:
+ case SWAUX_STATUS_I2C_NACK:
+ /*
+ * The programming guide is not clear about whether a I2C NACK
+ * would trigger SWAUX_STATUS_NACK or SWAUX_STATUS_I2C_NACK. So
+ * we handle both cases together.
+ */
+ if (is_native_aux)
+ msg->reply |= DP_AUX_NATIVE_REPLY_NACK;
+ else
+ msg->reply |= DP_AUX_I2C_REPLY_NACK;
+
+ fallthrough;
+ case SWAUX_STATUS_ACKM:
+ len = data & SWAUX_M_MASK;
+ break;
+ case SWAUX_STATUS_INVALID:
+ return -EOPNOTSUPP;
+ case SWAUX_STATUS_TIMEOUT:
+ return -ETIMEDOUT;
+ }
+
+ if (len && (request == DP_AUX_NATIVE_READ ||
+ request == DP_AUX_I2C_READ)) {
+ /* Read from the internal FIFO buffer */
+ for (i = 0; i < len; i++) {
+ ret = regmap_read(map, PAGE0_SWAUX_RDATA, &data);
+ if (ret) {
+ DRM_DEV_ERROR(dev,
+ "failed to read RDATA: %d\n",
+ ret);
+ return ret;
+ }
+
+ buf[i] = data;
+ }
+ }
+
+ return len;
+}
+
static int ps8640_bridge_vdo_control(struct ps8640 *ps_bridge,
const enum ps8640_vdo_control ctrl)
{
@@ -286,18 +443,34 @@ static int ps8640_bridge_attach(struct drm_bridge *bridge,
dsi->format = MIPI_DSI_FMT_RGB888;
dsi->lanes = NUM_MIPI_LANES;
ret = mipi_dsi_attach(dsi);
- if (ret)
+ if (ret) {
+ dev_err(dev, "failed to attach dsi device: %d\n", ret);
goto err_dsi_attach;
+ }
+
+ ret = drm_dp_aux_register(&ps_bridge->aux);
+ if (ret) {
+ dev_err(dev, "failed to register DP AUX channel: %d\n", ret);
+ goto err_aux_register;
+ }
/* Attach the panel-bridge to the dsi bridge */
return drm_bridge_attach(bridge->encoder, ps_bridge->panel_bridge,
&ps_bridge->bridge, flags);
+err_aux_register:
+ mipi_dsi_detach(dsi);
err_dsi_attach:
mipi_dsi_device_unregister(dsi);
return ret;
}
+
+static void ps8640_bridge_detach(struct drm_bridge *bridge)
+{
+ drm_dp_aux_unregister(&bridge_to_ps8640(bridge)->aux);
+}
+
static struct edid *ps8640_bridge_get_edid(struct drm_bridge *bridge,
struct drm_connector *connector)
{
@@ -334,6 +507,7 @@ static struct edid *ps8640_bridge_get_edid(struct drm_bridge *bridge,
static const struct drm_bridge_funcs ps8640_bridge_funcs = {
.attach = ps8640_bridge_attach,
+ .detach = ps8640_bridge_detach,
.get_edid = ps8640_bridge_get_edid,
.post_disable = ps8640_post_disable,
.pre_enable = ps8640_pre_enable,
@@ -409,6 +583,11 @@ static int ps8640_probe(struct i2c_client *client)
i2c_set_clientdata(client, ps_bridge);
+ ps_bridge->aux.name = "parade-ps8640-aux";
+ ps_bridge->aux.dev = dev;
+ ps_bridge->aux.transfer = ps8640_aux_transfer;
+ drm_dp_aux_init(&ps_bridge->aux);
+
drm_bridge_add(&ps_bridge->bridge);
return 0;
--
2.33.0.464.g1972c5931b-goog
More information about the dri-devel
mailing list