drm/omap: hdmi5: Rework EDID read to isolate data read

In preparation of adding DRM bridge support to the hdmi5 encoder code,
rework the EDID read to isolate data read.

The hdmi_read_edid() function is the main entry point. It performs all
initialisation steps required prior to reading the EDID (such as
ensuring the device is powered on), as well as corresponding cleanup
steps afterwards. EDID read itself is handled by hdmi_read_edid_data()
that calls the hdmi5_core_ddc_read() function to read individual blocks.

This new code architecture will allow reusing hdmi_read_edid() and
hdmi5_core_ddc_read() for the drm_bridge EDID read implementation, while
swapping out hdmi_read_edid_data() for the DRM drm_do_get_edid()
function.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Tested-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200226112514.12455-31-laurent.pinchart@ideasonboard.com

1 files changed, 8 insertions, 40 deletions

diff --git a/drivers/gpu/drm/omapdrm/dss/hdmi5_core.c b/drivers/gpu/drm/omapdrm/dss/hdmi5_core.c
index ff4d35c8771f..7dd587035160 100644
--- a/drivers/gpu/drm/omapdrm/dss/hdmi5_core.c
+++ b/drivers/gpu/drm/omapdrm/dss/hdmi5_core.c
@@ -23,7 +23,7 @@
 
 #include "hdmi5_core.h"
 
-static void hdmi_core_ddc_init(struct hdmi_core_data *core)
+void hdmi5_core_ddc_init(struct hdmi_core_data *core)
 {
 	void __iomem *base = core->base;
 	const unsigned long long iclk = 266000000;	/* DSS L3 ICLK */
@@ -102,7 +102,7 @@ static void hdmi_core_ddc_init(struct hdmi_core_data *core)
 	REG_FLD_MOD(base, HDMI_CORE_I2CM_INT, 0x0, 2, 2);
 }
 
-static void hdmi_core_ddc_uninit(struct hdmi_core_data *core)
+void hdmi5_core_ddc_uninit(struct hdmi_core_data *core)
 {
 	void __iomem *base = core->base;
 
@@ -112,14 +112,14 @@ static void hdmi_core_ddc_uninit(struct hdmi_core_data *core)
 	REG_FLD_MOD(base, HDMI_CORE_I2CM_INT, 0x1, 2, 2);
 }
 
-static int hdmi_core_ddc_edid(struct hdmi_core_data *core, u8 *pedid, u8 ext)
+int hdmi5_core_ddc_read(void *data, u8 *buf, unsigned int block, size_t len)
 {
+	struct hdmi_core_data *core = data;
 	void __iomem *base = core->base;
 	u8 cur_addr;
-	char checksum = 0;
 	const int retries = 1000;
-	u8 seg_ptr = ext / 2;
-	u8 edidbase = ((ext % 2) * 0x80);
+	u8 seg_ptr = block / 2;
+	u8 edidbase = ((block % 2) * EDID_LENGTH);
 
 	REG_FLD_MOD(base, HDMI_CORE_I2CM_SEGPTR, seg_ptr, 7, 0);
 
@@ -127,7 +127,7 @@ static int hdmi_core_ddc_edid(struct hdmi_core_data *core, u8 *pedid, u8 ext)
 	 * TODO: We use polling here, although we probably should use proper
 	 * interrupts.
 	 */
-	for (cur_addr = 0; cur_addr < 128; ++cur_addr) {
+	for (cur_addr = 0; cur_addr < len; ++cur_addr) {
 		int i;
 
 		/* clear ERROR and DONE */
@@ -164,45 +164,13 @@ static int hdmi_core_ddc_edid(struct hdmi_core_data *core, u8 *pedid, u8 ext)
 			return -EIO;
 		}
 
-		pedid[cur_addr] = REG_GET(base, HDMI_CORE_I2CM_DATAI, 7, 0);
-		checksum += pedid[cur_addr];
+		buf[cur_addr] = REG_GET(base, HDMI_CORE_I2CM_DATAI, 7, 0);
 	}
 
 	return 0;
 
 }
 
-int hdmi5_read_edid(struct hdmi_core_data *core, u8 *edid, int len)
-{
-	int r, n, i;
-	int max_ext_blocks = (len / 128) - 1;
-
-	if (len < 128)
-		return -EINVAL;
-
-	hdmi_core_ddc_init(core);
-
-	r = hdmi_core_ddc_edid(core, edid, 0);
-	if (r)
-		goto out;
-
-	n = edid[0x7e];
-
-	if (n > max_ext_blocks)
-		n = max_ext_blocks;
-
-	for (i = 1; i <= n; i++) {
-		r = hdmi_core_ddc_edid(core, edid + i * EDID_LENGTH, i);
-		if (r)
-			goto out;
-	}
-
-out:
-	hdmi_core_ddc_uninit(core);
-
-	return r ? r : len;
-}
-
 void hdmi5_core_dump(struct hdmi_core_data *core, struct seq_file *s)
 {