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drm/bridge: parade-ps8640: Add support for AUX channel
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Implement the first version of AUX support, which will be useful as
we expand the driver to support varied use cases.

Signed-off-by: Philip Chen <philipchen@chromium.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
[dianders: whitespace fixes reported by dim apply-branch]
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210921110556.v6.2.I1d6ea362dc76efa77cca2b46253d31b7651eaf17@changeid
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Philip Chen authored and Douglas Anderson committed Sep 23, 2021
1 parent 692d8db commit 13afcdd
Showing 1 changed file with 179 additions and 1 deletion.
180 changes: 179 additions & 1 deletion drivers/gpu/drm/bridge/parade-ps8640.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down Expand Up @@ -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];
Expand Down Expand Up @@ -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)
{
Expand Down Expand Up @@ -286,18 +443,33 @@ 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)
{
Expand Down Expand Up @@ -334,6 +506,7 @@ 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,
Expand Down Expand Up @@ -409,6 +582,11 @@ 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;
Expand Down

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