drm: Add MIPI read_multi func and two write macros

Create mipi_dsi_dcs_read_multi(), which accepts a mipi_dsi_multi_context
struct for improved error handling and cleaner panel driver code.

Create mipi_dsi_dcs_write_var_seq_multi() and
mipi_dsi_generic_write_var_seq_multi() macros which allow MIPI panel
drivers to write non-constant data to display controllers.

Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Brigham Campbell <me@brighamcampbell.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20250731032343.1258366-3-me@brighamcampbell.com

diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c
index fe03915d009515af2df664383cd008724e7349e7..a712e177b3506927302b643de25e44f10de46bfb 100644 (file)
--- a/drivers/gpu/drm/drm_mipi_dsi.c
+++ b/drivers/gpu/drm/drm_mipi_dsi.c
@@ -1096,6 +1096,43 @@ ssize_t mipi_dsi_dcs_read(struct mipi_dsi_device *dsi, u8 cmd, void *data,
 }
 EXPORT_SYMBOL(mipi_dsi_dcs_read);
 
+/**
+ * mipi_dsi_dcs_read_multi() - mipi_dsi_dcs_read() w/ accum_err
+ * @ctx: Context for multiple DSI transactions
+ * @cmd: DCS command
+ * @data: buffer in which to receive data
+ * @len: size of receive buffer
+ *
+ * Like mipi_dsi_dcs_read() but deals with errors in a way that makes it
+ * convenient to make several calls in a row.
+ */
+void mipi_dsi_dcs_read_multi(struct mipi_dsi_multi_context *ctx, u8 cmd,
+                            void *data, size_t len)
+{
+       struct mipi_dsi_device *dsi = ctx->dsi;
+       struct device *dev = &dsi->dev;
+       struct mipi_dsi_msg msg = {
+               .channel = dsi->channel,
+               .type = MIPI_DSI_DCS_READ,
+               .tx_buf = &cmd,
+               .tx_len = 1,
+               .rx_buf = data,
+               .rx_len = len
+       };
+       ssize_t ret;
+
+       if (ctx->accum_err)
+               return;
+
+       ret = mipi_dsi_device_transfer(dsi, &msg);
+       if (ret < 0) {
+               ctx->accum_err = ret;
+               dev_err(dev, "dcs read with command %#x failed: %d\n", cmd,
+                       ctx->accum_err);
+       }
+}
+EXPORT_SYMBOL(mipi_dsi_dcs_read_multi);
+
 /**
  * mipi_dsi_dcs_nop() - send DCS nop packet
  * @dsi: DSI peripheral device

diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
index 16eeb9552064489390709b94c0edbcbed9bce5e0..3aba7b380c8d6a6d75fabf8ef69a9b973664d19a 100644 (file)
--- a/include/drm/drm_mipi_dsi.h
+++ b/include/drm/drm_mipi_dsi.h
@@ -342,6 +342,8 @@ ssize_t mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, u8 cmd,
                           const void *data, size_t len);
 ssize_t mipi_dsi_dcs_read(struct mipi_dsi_device *dsi, u8 cmd, void *data,
                          size_t len);
+void mipi_dsi_dcs_read_multi(struct mipi_dsi_multi_context *ctx, u8 cmd,
+                            void *data, size_t len);
 int mipi_dsi_dcs_nop(struct mipi_dsi_device *dsi);
 int mipi_dsi_dcs_soft_reset(struct mipi_dsi_device *dsi);
 int mipi_dsi_dcs_get_power_mode(struct mipi_dsi_device *dsi, u8 *mode);
@@ -403,6 +405,22 @@ void mipi_dsi_dcs_set_tear_off_multi(struct mipi_dsi_multi_context *ctx);
                mipi_dsi_generic_write_multi(ctx, d, ARRAY_SIZE(d)); \
        } while (0)
 
+/**
+ * mipi_dsi_generic_write_var_seq_multi - transmit non-constant data using a
+ * generic write packet
+ *
+ * This macro will print errors for you and error handling is optimized for
+ * callers that call this multiple times in a row.
+ *
+ * @ctx: Context for multiple DSI transactions
+ * @seq: buffer containing the payload
+ */
+#define mipi_dsi_generic_write_var_seq_multi(ctx, seq...)           \
+       do {                                                         \
+               const u8 d[] = { seq };                              \
+               mipi_dsi_generic_write_multi(ctx, d, ARRAY_SIZE(d)); \
+       } while (0)
+
 /**
  * mipi_dsi_dcs_write_seq_multi - transmit a DCS command with payload
  *
@@ -419,6 +437,23 @@ void mipi_dsi_dcs_set_tear_off_multi(struct mipi_dsi_multi_context *ctx);
                mipi_dsi_dcs_write_buffer_multi(ctx, d, ARRAY_SIZE(d)); \
        } while (0)
 
+/**
+ * mipi_dsi_dcs_write_var_seq_multi - transmit a DCS command with non-constant
+ * payload
+ *
+ * This macro will print errors for you and error handling is optimized for
+ * callers that call this multiple times in a row.
+ *
+ * @ctx: Context for multiple DSI transactions
+ * @cmd: Command
+ * @seq: buffer containing data to be transmitted
+ */
+#define mipi_dsi_dcs_write_var_seq_multi(ctx, cmd, seq...)             \
+       do {                                                            \
+               const u8 d[] = { cmd, seq };                            \
+               mipi_dsi_dcs_write_buffer_multi(ctx, d, ARRAY_SIZE(d)); \
+       } while (0)
+
 /**
  * mipi_dsi_dual - send the same MIPI DSI command to two interfaces
  *