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 ---

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

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..31ec4a64de91 100644 --- a/drivers/gpu/drm/bridge/parade-ps8640.c +++ b/drivers/gpu/drm/bridge/parade-ps8640.c @@ -13,11 +13,37 @@ #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_19_16_MASK GENMASK(3, 0) +#define SWAUX_CMD_MASK GENMASK(7, 4) +#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 +94,7 @@ 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 +144,136 @@ 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 addr_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; + + 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; + + addr_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) & + SWAUX_ADDR_19_16_MASK + addr_len[PAGE0_SWAUX_ADDR_23_16 - base] |= (msg->request << 4) & + SWAUX_CMD_MASK; + 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, + (unsigned int *)(buf + i)); + if (ret) { + DRM_DEV_ERROR(dev, + "failed to read RDATA: %d\n", + ret); + return ret; + } + } + } + + 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;