Re: [PATCH v2 3/6] soc: qcom: geni-se: add desc struct to specify clocks from device match data

From: Neil Armstrong
Date: Tue Nov 29 2022 - 03:24:54 EST


On 18/11/2022 10:06, Konrad Dybcio wrote:


On 18/11/2022 09:45, Neil Armstrong wrote:
The I2C Master Hub is a stripped down version of the GENI Serial Engine
QUP Wrapper Controller but only supporting I2C serial engines without
DMA support.

Prepare support for the I2C Master Hub variant by moving the required
clocks list to a new desc struct then passing it through the compatible
match data.

Signed-off-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
Reviewed-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx>
---
  drivers/soc/qcom/qcom-geni-se.c | 59 +++++++++++++++++++++++++++++++----------
  1 file changed, 45 insertions(+), 14 deletions(-)

diff --git a/drivers/soc/qcom/qcom-geni-se.c b/drivers/soc/qcom/qcom-geni-se.c
index a0ceeede450f..ced2a2932eda 100644
--- a/drivers/soc/qcom/qcom-geni-se.c
+++ b/drivers/soc/qcom/qcom-geni-se.c
@@ -81,19 +81,31 @@
   */
  #define MAX_CLK_PERF_LEVEL 32
-#define NUM_AHB_CLKS 2
+#define MAX_CLKS 2
  /**
   * struct geni_wrapper - Data structure to represent the QUP Wrapper Core
   * @dev:        Device pointer of the QUP wrapper core
   * @base:        Base address of this instance of QUP wrapper core
- * @ahb_clks:        Handle to the primary & secondary AHB clocks
+ * @clks:        Handle to the primary & optional secondary AHB clocks
+ * @num_clks:        Count of clocks
   * @to_core:        Core ICC path
   */
  struct geni_wrapper {
      struct device *dev;
      void __iomem *base;
-    struct clk_bulk_data ahb_clks[NUM_AHB_CLKS];
+    struct clk_bulk_data clks[MAX_CLKS];
+    unsigned int num_clks;
+};
+
+/**
+ * struct geni_se_desc - Data structure to represent the QUP Wrapper resources
+ * @clks:        Name of the primary & optional secondary AHB clocks
+ * @num_clks:        Count of clock names
+ */
+struct geni_se_desc {
+    unsigned int num_clks;
+    const char * const *clks;
  };
  static const char * const icc_path_names[] = {"qup-core", "qup-config",
@@ -496,8 +508,7 @@ static void geni_se_clks_off(struct geni_se *se)
      struct geni_wrapper *wrapper = se->wrapper;
      clk_disable_unprepare(se->clk);
-    clk_bulk_disable_unprepare(ARRAY_SIZE(wrapper->ahb_clks),
-                        wrapper->ahb_clks);
+    clk_bulk_disable_unprepare(wrapper->num_clks, wrapper->clks);
  }
  /**
@@ -528,15 +539,13 @@ static int geni_se_clks_on(struct geni_se *se)
      int ret;
      struct geni_wrapper *wrapper = se->wrapper;
-    ret = clk_bulk_prepare_enable(ARRAY_SIZE(wrapper->ahb_clks),
-                        wrapper->ahb_clks);
+    ret = clk_bulk_prepare_enable(wrapper->num_clks, wrapper->clks);
      if (ret)
          return ret;
      ret = clk_prepare_enable(se->clk);
      if (ret)
-        clk_bulk_disable_unprepare(ARRAY_SIZE(wrapper->ahb_clks),
-                            wrapper->ahb_clks);
+        clk_bulk_disable_unprepare(wrapper->num_clks, wrapper->clks);
      return ret;
  }
@@ -887,11 +896,23 @@ static int geni_se_probe(struct platform_device *pdev)
          return PTR_ERR(wrapper->base);
      if (!has_acpi_companion(&pdev->dev)) {
-        wrapper->ahb_clks[0].id = "m-ahb";
-        wrapper->ahb_clks[1].id = "s-ahb";
-        ret = devm_clk_bulk_get(dev, NUM_AHB_CLKS, wrapper->ahb_clks);
+        const struct geni_se_desc *desc;
+        int i;
+
+        desc = device_get_match_data(&pdev->dev);
+        if (!desc)
+            return -EINVAL;
+
+        wrapper->num_clks = min_t(unsigned int, desc->num_clks, MAX_CLKS);
+        if (wrapper->num_clks < desc->num_clks)
This will never execute (except if somebody adding a third desc would make a mistake or not update MAX_CLKS), as wrapper->num_clks will only be < desc->num_clks if desc->num_clks > MAX_CLKS.

You're right, I did read too fast.


I was thinking about getting the number of actual clocks passed to the device in the DT, but I can't find a helper function for that, so it would probably require some kind of manual looping.. I guess we can drop this. Or leave it to save somebody pulling their hair out in an unlikely event. I guess I'm fine with both.

This would be:

of_count_phandle_with_args(dev->of_node, "clocks", "#clock-cells")

but ultimately if the number of clocks is lower than requested, it will fail
in the call to devm_clk_bulk_get().

Would we warn if the DT clocks count is higher ? or simply fail if lower ?

Neil



+            dev_warn(dev, "too much clocks described in DT\n")
If you leave it, s/too much/Too many/


Konrad
+
+        for (i = 0; i < wrapper->num_clks; ++i)
+            wrapper->clks[i].id = desc->clks[i];
+
+        ret = devm_clk_bulk_get(dev, wrapper->num_clks, wrapper->clks);
          if (ret) {
-            dev_err(dev, "Err getting AHB clks %d\n", ret);
+            dev_err(dev, "Err getting clks %d\n", ret);
              return ret;
          }
      }
@@ -901,8 +922,18 @@ static int geni_se_probe(struct platform_device *pdev)
      return devm_of_platform_populate(dev);
  }
+static const char * const qup_clks[] = {
+    "m-ahb",
+    "s-ahb",
+};
+
+static const struct geni_se_desc qup_desc = {
+    .clks = qup_clks,
+    .num_clks = ARRAY_SIZE(qup_clks),
+};
+
  static const struct of_device_id geni_se_dt_match[] = {
-    { .compatible = "qcom,geni-se-qup", },
+    { .compatible = "qcom,geni-se-qup", .data = &qup_desc },
      {}
  };
  MODULE_DEVICE_TABLE(of, geni_se_dt_match);