Hi Bjorn,
On 8/24/2016 10:26 PM, Bjorn Andersson wrote:
On Mon 22 Aug 23:35 PDT 2016, Ritesh Harjani wrote:
Hi Bjorn,
On 8/23/2016 10:01 AM, Bjorn Andersson wrote:
On Thu 18 Aug 21:36 PDT 2016, Ritesh Harjani wrote:
This adds support for sdhc-msm controllers to get supported
clk-rates from DT. sdhci-msm would need it's own set_clock
ops to be implemented. For this, supported clk-rates needs
to be populated in sdhci_msm_pltfm_data.
Signed-off-by: Ritesh Harjani <riteshh@xxxxxxxxxxxxxx>
---
.../devicetree/bindings/mmc/sdhci-msm.txt | 1 +
drivers/mmc/host/sdhci-msm.c | 71 ++++++++++++++++++++++
2 files changed, 72 insertions(+)
diff --git a/Documentation/devicetree/bindings/mmc/sdhci-msm.txt b/Documentation/devicetree/bindings/mmc/sdhci-msm.txt
index 485483a..6a83b38 100644
--- a/Documentation/devicetree/bindings/mmc/sdhci-msm.txt
+++ b/Documentation/devicetree/bindings/mmc/sdhci-msm.txt
@@ -17,6 +17,7 @@ Required properties:
"iface" - Main peripheral bus clock (PCLK/HCLK - AHB Bus clock) (required)
"core" - SDC MMC clock (MCLK) (required)
"bus" - SDCC bus voter clock (optional)
+- clk-rates: Array of supported GCC clock frequencies for sdhc, Units - Hz.
Example:
diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
index 85ddaae..2bf141b 100644
--- a/drivers/mmc/host/sdhci-msm.c
+++ b/drivers/mmc/host/sdhci-msm.c
@@ -74,6 +74,11 @@
#define CMUX_SHIFT_PHASE_SHIFT 24
#define CMUX_SHIFT_PHASE_MASK (7 << CMUX_SHIFT_PHASE_SHIFT)
+struct sdhci_msm_pltfm_data {
+ u32 *clk_table;
+ size_t clk_table_sz;
+};
Rather than calling this "platform data", just call it
sdhci_msm_freq_table and make it:
Going ahead this sdhci_msm_pltfm_data will be needed to store
other stuff as well, hence it will be preferable to have it as pltfm_data
only.
Ok, that's fine then.
[..]
Adding this as a requirement breaks existing platforms/dtbs, you may
force it for 8996 if you can detect that, but you should not change it
for existing platforms.
Ok, good point and thanks for catching it.
Actually I checked all arch/arm64 dts files and could only see 8916.dtsi.
But I think there would be changes required for arch/arm dts files as well.
In that case I will add clk entries to other boards as well.
I will check and see if I can get any of this board to test it on as well.
In the upstream kernel you should be compatible with older DTBs, so
while it's good that you're adding this to the arm dts files, the code
should continue to function without this property - e.g. by falling back
to default values or skipping the new functionality.
sdhci-msm driver in upstream supports only basic functionality as of
now. There is a lot more to be added to upstream driver (like, HW
recommendations, bus speed modes, bus-voting, scaling feature, pm_qos
and a lot more).
This patch addresses few clock related changes which is as per HW
recommendation only. Going ahead there will be more changes which will
be coming in which may have a dependency with clk-rates.
Also, we added clk-rates into all sdhc DT nodes of MSM platforms in
upstream.
But I understand your concern that even without this property the basic
msm driver support should work.
Let me spin version(v5) of this patch series after addressing your concern.
Do you think it will be ok to follow below approach -
1. Let clk-rates be *required properties* in DT file (since this is as
per HW recommendation).
2. Print a warning if clk-rates property is not mentioned in DT.
3. Still continue to support basic msm driver even without this property.
Please let me know if you have anything else to be addressed as well?
(Unless there's a really really good reason for breaking this
compatibility)
Regards,
Bjorn
Regards
Ritesh
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