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Date: Mon, 13 Sep 2021 14:33:44 -0700
From: Philip Chen <philipchen@...omium.org>
To: LKML <linux-kernel@...r.kernel.org>
Cc: dianders@...omium.org, swboyd@...omium.org,
Philip Chen <philipchen@...omium.org>,
Andrzej Hajda <a.hajda@...sung.com>,
Daniel Vetter <daniel@...ll.ch>,
David Airlie <airlied@...ux.ie>,
Jernej Skrabec <jernej.skrabec@...il.com>,
Jonas Karlman <jonas@...boo.se>,
Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
Neil Armstrong <narmstrong@...libre.com>,
Robert Foss <robert.foss@...aro.org>,
dri-devel@...ts.freedesktop.org
Subject: [RFC PATCH v2 2/2] drm/bridge: parade-ps8640: Add support for AUX channel
Implement the first version of AUX support, which will be useful as
we expand the driver to support varied use cases.
WARNING: This patch is not fully verified by hardware. But as AUX CH
is not implemented for ps8640 driver until now, the patch shouldn't
cause any functional regression in practice.
Signed-off-by: Philip Chen <philipchen@...omium.org>
---
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 mesages
drivers/gpu/drm/bridge/parade-ps8640.c | 156 ++++++++++++++++++++++++-
1 file changed, 153 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c
index 1b2414601538..3b28e992bb3e 100644
--- a/drivers/gpu/drm/bridge/parade-ps8640.c
+++ b/drivers/gpu/drm/bridge/parade-ps8640.c
@@ -13,11 +13,32 @@
#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_AUX_ADDR_7_0 0x7d
+#define PAGE0_AUX_ADDR_15_8 0x7e
+#define PAGE0_AUX_ADDR_23_16 0x7f
+#define AUX_ADDR_19_16_MASK GENMASK(3, 0)
+#define AUX_CMD_MASK GENMASK(7, 4)
+#define PAGE0_AUX_LENGTH 0x80
+#define AUX_LENGTH_MASK GENMASK(3, 0)
+#define AUX_NO_PAYLOAD BIT(7)
+#define PAGE0_AUX_WDATA 0x81
+#define PAGE0_AUX_RDATA 0x82
+#define PAGE0_AUX_CTRL 0x83
+#define AUX_SEND BIT(0)
+#define PAGE0_AUX_STATUS 0x84
+#define AUX_STATUS_MASK GENMASK(7, 5)
+#define AUX_STATUS_TIMEOUT (0x7 << 5)
+#define AUX_STATUS_DEFER (0x2 << 5)
+#define AUX_STATUS_NACK (0x1 << 5)
+
#define PAGE2_GPIO_H 0xa7
#define PS_GPIO9 BIT(1)
#define PAGE2_I2C_BYPASS 0xea
@@ -68,6 +89,7 @@ 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 +139,114 @@ 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];
+ unsigned int len = msg->size;
+ unsigned int data;
+ int ret;
+ u8 request = msg->request &
+ ~(DP_AUX_I2C_MOT | DP_AUX_I2C_WRITE_STATUS_UPDATE);
+ u8 *buf = msg->buffer;
+ u8 addr_len[PAGE0_AUX_LENGTH + 1 - PAGE0_AUX_ADDR_7_0];
+ u8 i;
+ bool is_native_aux = false;
+
+ if (len > DP_AUX_MAX_PAYLOAD_BYTES)
+ return -EINVAL;
+
+ switch (request) {
+ case DP_AUX_NATIVE_WRITE:
+ case DP_AUX_NATIVE_READ:
+ is_native_aux = true;
+ case DP_AUX_I2C_WRITE:
+ case DP_AUX_I2C_READ:
+ ret = regmap_write(map, PAGE0_AUXCH_CFG3, AUXCH_CFG3_RESET);
+ break;
+ default:
+ ret = -EINVAL;
+ goto exit;
+ }
+
+ /* Assume it's good */
+ msg->reply = 0;
+
+ addr_len[0] = msg->address & 0xff;
+ addr_len[1] = (msg->address >> 8) & 0xff;
+ addr_len[2] = ((request << 4) & AUX_CMD_MASK) |
+ ((msg->address >> 16) & AUX_ADDR_19_16_MASK);
+ addr_len[3] = (len == 0) ? AUX_NO_PAYLOAD :
+ ((len - 1) & AUX_LENGTH_MASK);
+
+ regmap_bulk_write(map, PAGE0_AUX_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_AUX_WDATA, buf[i]);
+ if (ret < 0) {
+ DRM_ERROR("failed to write PAGE0_AUX_WDATA\n");
+ goto exit;
+ }
+ }
+ }
+
+ regmap_write(map, PAGE0_AUX_CTRL, AUX_SEND);
+
+ /* Zero delay loop because i2c transactions are slow already */
+ ret = regmap_read_poll_timeout(map, PAGE0_AUX_CTRL, data,
+ !(data & AUX_SEND), 0, 50 * 1000);
+ if (ret)
+ goto exit;
+
+ regmap_read(map, PAGE0_AUX_STATUS, &data);
+ switch (data & AUX_STATUS_MASK) {
+ case AUX_STATUS_DEFER:
+ if (is_native_aux)
+ msg->reply |= DP_AUX_NATIVE_REPLY_DEFER;
+ else
+ msg->reply |= DP_AUX_I2C_REPLY_DEFER;
+ ret = -EBUSY;
+ goto exit;
+ case AUX_STATUS_NACK:
+ if (is_native_aux)
+ msg->reply |= DP_AUX_NATIVE_REPLY_NACK;
+ else
+ msg->reply |= DP_AUX_I2C_REPLY_NACK;
+ ret = -EBUSY;
+ goto exit;
+ case AUX_STATUS_TIMEOUT:
+ ret = -ETIMEDOUT;
+ goto exit;
+ }
+
+ 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_AUX_WDATA, &data);
+ buf[i] = data;
+ if (ret < 0)
+ DRM_ERROR("failed to read PAGE0_AUX_RDATA\n");
+ }
+ }
+
+exit:
+ if (ret)
+ return ret;
+
+ return len;
+}
+
static int ps8640_bridge_vdo_control(struct ps8640 *ps_bridge,
const enum ps8640_vdo_control ctrl)
{
@@ -286,18 +416,32 @@ 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)
- goto err_dsi_attach;
+ if (ret) {
+ dev_err(dev, "failed to attach dsi device: %d\n", ret);
+ goto exit;
+ }
+
+ ret = drm_dp_aux_register(&ps_bridge->aux);
+ if (ret) {
+ dev_err(dev, "failed to register DP AUX channel: %d\n", ret);
+ goto exit;
+ }
/* Attach the panel-bridge to the dsi bridge */
return drm_bridge_attach(bridge->encoder, ps_bridge->panel_bridge,
&ps_bridge->bridge, flags);
-err_dsi_attach:
+exit:
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 +478,7 @@ 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,
@@ -412,6 +557,11 @@ 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;
--
2.33.0.309.g3052b89438-goog
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