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SubjectRe: [PATCH v4 7/7] clk: qcom: add the driver for the MSM8996 APCS clocks
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Quoting Dmitry Baryshkov (2023-01-18 05:22:54)
> 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);

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