[PATCH v2 2/6] media: qcom: camss: clamp VFE clock rates to the highest level

[Atanas Filipov <atanas.filipov@oss.qualcomm.com>]

The VFE fails to power on when the pixel rate exceeds the highest rate
listed for any of its clocks. The rate tables of the VFE clocks are
independent and need not have the same number of levels, so a clock
with a lower top rate than the VFE core clock, such as the SC7280
camnoc_axi clock, makes the VFE reject pixel rates the core clock
still supports.

Clamp each clock to its highest listed rate instead, and warn that the
pixel rate exceeds it when the clock lists more than one rate. Take the
clamp into account when another line powers on an already running VFE,
so that a clock running at its highest rate does not reject the
request.

Signed-off-by: Atanas Filipov <atanas.filipov@oss.qualcomm.com>
---
 drivers/media/platform/qcom/camss/camss-vfe.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/media/platform/qcom/camss/camss-vfe.c b/drivers/media/platform/qcom/camss/camss-vfe.c
index 59be37f83df3..359b5942df89 100644
--- a/drivers/media/platform/qcom/camss/camss-vfe.c
+++ b/drivers/media/platform/qcom/camss/camss-vfe.c
@@ -996,15 +996,13 @@ static int vfe_set_clock_rates(struct vfe_device *vfe)
 		if (vfe_match_clock_names(vfe, clock) && vfe_check_clock_levels(clock)) {
 			long rate;
 
-			for (j = 0; j < clock->nfreqs; j++)
+			for (j = 0; j < clock->nfreqs - 1; j++)
 				if (min_rate < clock->freq[j])
 					break;
 
-			if (j == clock->nfreqs) {
-				dev_err(dev,
-					"Pixel clock is too high for VFE");
-				return -EINVAL;
-			}
+			if (clock->nfreqs > 1 && min_rate >= clock->freq[j])
+				dev_warn(dev, "Pixel clock is too high for VFE clock %s\n",
+					 clock->name);
 
 			/* if sensor pixel clock is not available */
 			/* set highest possible VFE clock rate */
@@ -1046,9 +1044,15 @@ static int vfe_check_clock_rates(struct vfe_device *vfe)
 
 		if (vfe_match_clock_names(vfe, clock) && vfe_check_clock_levels(clock)) {
 			unsigned long rate;
+			long max_rate;
+
+			/* A clock already at its highest rate cannot go higher */
+			max_rate = clk_round_rate(clock->clk, clock->freq[clock->nfreqs - 1]);
+			if (max_rate < 0)
+				return max_rate;
 
 			rate = clk_get_rate(clock->clk);
-			if (rate < min_rate)
+			if (rate < min_t(u64, min_rate, max_rate))
 				return -EBUSY;
 		}
 	}
-- 
2.34.1