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Subject[PATCH v2 08/11] mmc: sdhci-of-arasan: Add support to set clock phase delays for SD
Date
Add support to read Clock Phase Delays from the DT and set it via
clk_set_phase() API from clock framework. Some of the controllers might
have their own handling of setting clock delays, for this keep the
set_clk_delays as function pointer which can be assigned controller
specific handling of the same.

Signed-off-by: Manish Narani <manish.narani@xilinx.com>
---
drivers/mmc/host/sdhci-of-arasan.c | 91 ++++++++++++++++++++++++++++++++++++++
1 file changed, 91 insertions(+)

diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
index 9513813..a545221 100644
--- a/drivers/mmc/host/sdhci-of-arasan.c
+++ b/drivers/mmc/host/sdhci-of-arasan.c
@@ -77,12 +77,18 @@ struct sdhci_arasan_soc_ctl_map {
* @sdcardclk: Pointer to normal 'struct clock' for sdcardclk_hw.
* @sampleclk_hw: Struct for the clock we might provide to a PHY.
* @sampleclk: Pointer to normal 'struct clock' for sampleclk_hw.
+ * @clk_phase_in: Array of Input Clock Phase Delays for all speed modes
+ * @clk_phase_out: Array of Output Clock Phase Delays for all speed modes
+ * @set_clk_delays: Function pointer for setting Clock Delays
*/
struct sdhci_arasan_clk_data {
struct clk_hw sdcardclk_hw;
struct clk *sdcardclk;
struct clk_hw sampleclk_hw;
struct clk *sampleclk;
+ int clk_phase_in[MMC_TIMING_MMC_HS400 + 1];
+ int clk_phase_out[MMC_TIMING_MMC_HS400 + 1];
+ void (*set_clk_delays)(struct sdhci_host *host);
};

/**
@@ -180,6 +186,7 @@ static void sdhci_arasan_set_clock(struct sdhci_host *host, unsigned int clock)
{
struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
+ struct sdhci_arasan_clk_data *clk_data = &sdhci_arasan->clk_data;
bool ctrl_phy = false;

if (!IS_ERR(sdhci_arasan->phy)) {
@@ -221,6 +228,10 @@ static void sdhci_arasan_set_clock(struct sdhci_host *host, unsigned int clock)
sdhci_arasan->is_phy_on = false;
}

+ /* Set the Input and Output Clock Phase Delays */
+ if (clk_data->set_clk_delays)
+ clk_data->set_clk_delays(host);
+
sdhci_set_clock(host, clock);

if (sdhci_arasan->quirks & SDHCI_ARASAN_QUIRK_CLOCK_UNSTABLE)
@@ -635,6 +646,84 @@ static void sdhci_arasan_update_baseclkfreq(struct sdhci_host *host)
sdhci_arasan_syscon_write(host, &soc_ctl_map->baseclkfreq, mhz);
}

+static void sdhci_arasan_set_clk_delays(struct sdhci_host *host)
+{
+ struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+ struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
+ struct sdhci_arasan_clk_data *clk_data = &sdhci_arasan->clk_data;
+
+ clk_set_phase(clk_data->sampleclk,
+ clk_data->clk_phase_in[host->timing]);
+ clk_set_phase(clk_data->sdcardclk,
+ clk_data->clk_phase_out[host->timing]);
+}
+
+static void arasan_dt_read_clk_phase(struct device *dev,
+ struct sdhci_arasan_clk_data *clk_data,
+ unsigned int timing, const char *prop)
+{
+ struct device_node *np = dev->of_node;
+
+ int clk_phase[2] = {0};
+
+ /*
+ * Read Tap Delay values from DT, if the DT does not contain the
+ * Tap Values then use the pre-defined values.
+ */
+ if (of_property_read_variable_u32_array(np, prop, &clk_phase[0],
+ 2, 0)) {
+ dev_dbg(dev, "Using predefined clock phase for %s = %d %d\n",
+ prop, clk_data->clk_phase_in[timing],
+ clk_data->clk_phase_out[timing]);
+ return;
+ }
+
+ /* The values read are Input and Output Clock Delays in order */
+ clk_data->clk_phase_in[timing] = clk_phase[0];
+ clk_data->clk_phase_out[timing] = clk_phase[1];
+}
+
+/**
+ * arasan_dt_parse_clk_phases - Read Clock Delay values from DT
+ *
+ * Called at initialization to parse the values of Clock Delays.
+ *
+ * @dev: Pointer to our struct device.
+ */
+static void arasan_dt_parse_clk_phases(struct device *dev,
+ struct sdhci_arasan_clk_data *clk_data)
+{
+ /*
+ * This has been kept as a pointer and is assigned a function here.
+ * So that different controller variants can assign their own handling
+ * function.
+ */
+ clk_data->set_clk_delays = sdhci_arasan_set_clk_delays;
+
+ arasan_dt_read_clk_phase(dev, clk_data, MMC_TIMING_LEGACY,
+ "clk-phase-legacy");
+ arasan_dt_read_clk_phase(dev, clk_data, MMC_TIMING_MMC_HS,
+ "clk-phase-mmc-hs");
+ arasan_dt_read_clk_phase(dev, clk_data, MMC_TIMING_SD_HS,
+ "clk-phase-sd-hs");
+ arasan_dt_read_clk_phase(dev, clk_data, MMC_TIMING_UHS_SDR12,
+ "clk-phase-uhs-sdr12");
+ arasan_dt_read_clk_phase(dev, clk_data, MMC_TIMING_UHS_SDR25,
+ "clk-phase-uhs-sdr25");
+ arasan_dt_read_clk_phase(dev, clk_data, MMC_TIMING_UHS_SDR50,
+ "clk-phase-uhs-sdr50");
+ arasan_dt_read_clk_phase(dev, clk_data, MMC_TIMING_UHS_SDR104,
+ "clk-phase-uhs-sdr104");
+ arasan_dt_read_clk_phase(dev, clk_data, MMC_TIMING_UHS_DDR50,
+ "clk-phase-uhs-ddr50");
+ arasan_dt_read_clk_phase(dev, clk_data, MMC_TIMING_MMC_DDR52,
+ "clk-phase-mmc-ddr52");
+ arasan_dt_read_clk_phase(dev, clk_data, MMC_TIMING_MMC_HS200,
+ "clk-phase-mmc-hs200");
+ arasan_dt_read_clk_phase(dev, clk_data, MMC_TIMING_MMC_HS400,
+ "clk-phase-mmc-hs400");
+}
+
/**
* sdhci_arasan_register_sdcardclk - Register the sdcardclk for a PHY to use
*
@@ -923,6 +1012,8 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
if (ret)
goto unreg_clk;

+ arasan_dt_parse_clk_phases(&pdev->dev, &sdhci_arasan->clk_data);
+
ret = mmc_of_parse(host->mmc);
if (ret) {
if (ret != -EPROBE_DEFER)
--
2.1.1
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