From ffc23a204a5f2e763a8cc8a8cfefe0027a6f0ec3 Mon Sep 17 00:00:00 2001 From: Brigham Campbell Date: Wed, 30 Jul 2025 21:23:42 -0600 Subject: [PATCH 4756/5403] 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 Signed-off-by: Brigham Campbell Signed-off-by: Douglas Anderson Link: https://lore.kernel.org/r/20250731032343.1258366-3-me@brighamcampbell.com --- drivers/gpu/drm/drm_mipi_dsi.c | 37 ++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c index fe03915d0095..a712e177b350 100644 --- 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 -- 2.54.0