Re: [PATCH v4 7/7] clk: qcom: add the driver for the MSM8996 APCS clocks
From: Stephen Boyd <sboyd@kernel.org>
Date: 2023-01-25 21:38:25
Also in:
linux-arm-msm, linux-clk, lkml
Quoting Dmitry Baryshkov (2023-01-18 05:22:54)
quoted hunk ↗ jump to hunk
diff --git a/drivers/clk/qcom/apcs-msm8996.c b/drivers/clk/qcom/apcs-msm8996.c new file mode 100644 index 000000000000..7e46ea8ed444 --- /dev/null +++ b/drivers/clk/qcom/apcs-msm8996.c@@ -0,0 +1,76 @@
[...]
+
+static int qcom_apcs_msm8996_clk_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device *parent = dev->parent;
+ struct regmap *regmap;
+ struct clk_hw *hw;
+ unsigned int val;
+ int ret = -ENODEV;
+
+ regmap = dev_get_regmap(parent, NULL);
+ if (!regmap) {
+ dev_err(dev, "failed to get regmap: %d\n", ret);
+ return ret;
+ }
+
+ regmap_read(regmap, APCS_AUX_OFFSET, &val);
+ regmap_update_bits(regmap, APCS_AUX_OFFSET, APCS_AUX_DIV_MASK,
+ FIELD_PREP(APCS_AUX_DIV_MASK, APCS_AUX_DIV_2));
+
+ /* Hardware mandated delay */Delay for what? Setting the divider? What if the register value didn't change at all? Can you skip the delay in that case?
+ udelay(5); + + /* + * Register the clock as fixed rate instead of being a child of gpll0 + * to let the driver register probe as early as possible.
The function doesn't block or return EPROBE_DEFER if the clk is orphaned when registered. Why is this necessary? Are you getting defered by the fw_devlink logic thinking it needs to defer probe of this driver until gpll0 provider probes? We should fix fw_devlink to not do that. Maybe if the node is a clk provider (#clock-cells exists) then we don't wait for clocks property to be provided, because the clk core already handles that itself.
+ */ + hw = devm_clk_hw_register_fixed_rate(dev, "sys_apcs_aux", NULL, 0, 300000000);