6.17-stable review patch. If anyone has any objections, please let me know.
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From: Laurent Pinchart laurent.pinchart@ideasonboard.com
[ Upstream commit 65673c6e33cf46f220cc5774166b373b3c087739 ]
The imx-mipi-csis driver sets the rate of the wrap clock to the value specified in the device tree's "clock-frequency" property, and defaults to 166 MHz otherwise. This is a historical mistake, as clock rate selection should have been left to the assigned-clock-rates property.
Honouring the clock-frequency property can't be removed without breaking backwards compatibility, and the corresponding code isn't very intrusive. The 166 MHz default, on the other hand, prevents configuration of the clock rate through assigned-clock-rates, as the driver immediately overwrites the rate. This behaviour is confusing and has cost debugging time.
There is little value in a 166 MHz default. All mainline device tree sources that enable the CSIS specify a clock-frequency explicitly, and the default wrap clock configuration on supported platforms is at least as high as 166 MHz. Drop the default, and only set the clock rate manually when the clock-frequency property is specified.
Link: https://lore.kernel.org/r/20250822002734.23516-10-laurent.pinchart@ideasonbo... Signed-off-by: Laurent Pinchart laurent.pinchart@ideasonboard.com Reviewed-by: Frank Li Frank.Li@nxp.com Signed-off-by: Hans Verkuil hverkuil+cisco@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/media/platform/nxp/imx-mipi-csis.c | 23 +++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-)
diff --git a/drivers/media/platform/nxp/imx-mipi-csis.c b/drivers/media/platform/nxp/imx-mipi-csis.c index 2beb5f43c2c01..cea017a2b14ec 100644 --- a/drivers/media/platform/nxp/imx-mipi-csis.c +++ b/drivers/media/platform/nxp/imx-mipi-csis.c @@ -228,8 +228,6 @@ #define MIPI_CSIS_PKTDATA_EVEN 0x3000 #define MIPI_CSIS_PKTDATA_SIZE SZ_4K
-#define DEFAULT_SCLK_CSIS_FREQ 166000000UL - struct mipi_csis_event { bool debug; u32 mask; @@ -704,12 +702,17 @@ static int mipi_csis_clk_get(struct mipi_csis_device *csis) if (ret < 0) return ret;
- /* Set clock rate */ - ret = clk_set_rate(csis->clks[MIPI_CSIS_CLK_WRAP].clk, - csis->clk_frequency); - if (ret < 0) - dev_err(csis->dev, "set rate=%d failed: %d\n", - csis->clk_frequency, ret); + if (csis->clk_frequency) { + /* + * Set the clock rate. This is deprecated, for backward + * compatibility with old device trees. + */ + ret = clk_set_rate(csis->clks[MIPI_CSIS_CLK_WRAP].clk, + csis->clk_frequency); + if (ret < 0) + dev_err(csis->dev, "set rate=%d failed: %d\n", + csis->clk_frequency, ret); + }
return ret; } @@ -1413,9 +1416,7 @@ static int mipi_csis_parse_dt(struct mipi_csis_device *csis) { struct device_node *node = csis->dev->of_node;
- if (of_property_read_u32(node, "clock-frequency", - &csis->clk_frequency)) - csis->clk_frequency = DEFAULT_SCLK_CSIS_FREQ; + of_property_read_u32(node, "clock-frequency", &csis->clk_frequency);
return 0; }