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Subject[PATCH v2 2/2] mmc: sdhci-msm: Enable delay circuit calibration clocks
Date
The delay circuit used to support HS400 is calibrated based on two
additional clocks. When these clocks are not available and
FF_CLK_SW_RST_DIS is not set in CORE_HC_MODE, reset might fail. But on
some platforms this doesn't work properly and below dump can be seen in
the kernel log.

mmc0: Reset 0x1 never completed.
mmc0: sdhci: ============ SDHCI REGISTER DUMP ===========
mmc0: sdhci: Sys addr: 0x00000000 | Version: 0x00001102
mmc0: sdhci: Blk size: 0x00004000 | Blk cnt: 0x00000000
mmc0: sdhci: Argument: 0x00000000 | Trn mode: 0x00000000
mmc0: sdhci: Present: 0x01f80000 | Host ctl: 0x00000000
mmc0: sdhci: Power: 0x00000000 | Blk gap: 0x00000000
mmc0: sdhci: Wake-up: 0x00000000 | Clock: 0x00000002
mmc0: sdhci: Timeout: 0x00000000 | Int stat: 0x00000000
mmc0: sdhci: Int enab: 0x00000000 | Sig enab: 0x00000000
mmc0: sdhci: AC12 err: 0x00000000 | Slot int: 0x00000000
mmc0: sdhci: Caps: 0x742dc8b2 | Caps_1: 0x00008007
mmc0: sdhci: Cmd: 0x00000000 | Max curr: 0x00000000
mmc0: sdhci: Resp[0]: 0x00000000 | Resp[1]: 0x00000000
mmc0: sdhci: Resp[2]: 0x00000000 | Resp[3]: 0x00000000
mmc0: sdhci: Host ctl2: 0x00000000
mmc0: sdhci: ============================================

Add support for the additional calibration clocks to allow these
platforms to be configured appropriately.

Cc: Venkat Gopalakrishnan <venkatg@codeaurora.org>
Cc: Ritesh Harjani <riteshh@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---

Changes since v1:
- Add new clocks to DT binding

Documentation/devicetree/bindings/mmc/sdhci-msm.txt | 2 ++
drivers/mmc/host/sdhci-msm.c | 12 +++++++++++-
2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/mmc/sdhci-msm.txt b/Documentation/devicetree/bindings/mmc/sdhci-msm.txt
index 0576264eab5e..5d9c3cd1bdaa 100644
--- a/Documentation/devicetree/bindings/mmc/sdhci-msm.txt
+++ b/Documentation/devicetree/bindings/mmc/sdhci-msm.txt
@@ -18,6 +18,8 @@ Required properties:
"core" - SDC MMC clock (MCLK) (required)
"bus" - SDCC bus voter clock (optional)
"xo" - TCXO clock (optional)
+ "cal" - reference clock for RCLK delay calibration (optional)
+ "sleep" - sleep clock for RCLK delay calibration (optional)

Example:

diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
index b9ca1b1ef9a8..ea330e8169dc 100644
--- a/drivers/mmc/host/sdhci-msm.c
+++ b/drivers/mmc/host/sdhci-msm.c
@@ -129,7 +129,7 @@ struct sdhci_msm_host {
int pwr_irq; /* power irq */
struct clk *bus_clk; /* SDHC bus voter clock */
struct clk *xo_clk; /* TCXO clk needed for FLL feature of cm_dll*/
- struct clk_bulk_data bulk_clks[2]; /* core, iface clocks */
+ struct clk_bulk_data bulk_clks[4]; /* core, iface, cal, sleep clocks */
unsigned long clk_rate;
struct mmc_host *mmc;
bool use_14lpp_dll_reset;
@@ -1183,6 +1183,16 @@ static int sdhci_msm_probe(struct platform_device *pdev)
if (ret)
dev_warn(&pdev->dev, "core clock boost failed\n");

+ clk = devm_clk_get(&pdev->dev, "cal");
+ if (IS_ERR(clk))
+ clk = NULL;
+ msm_host->bulk_clks[2].clk = clk;
+
+ clk = devm_clk_get(&pdev->dev, "sleep");
+ if (IS_ERR(clk))
+ clk = NULL;
+ msm_host->bulk_clks[3].clk = clk;
+
ret = clk_bulk_prepare_enable(ARRAY_SIZE(msm_host->bulk_clks),
msm_host->bulk_clks);
if (ret)
--
2.12.0
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