Messages in this thread | | | Date | Thu, 24 Feb 2022 15:58:16 +0000 | Subject | Re: [PATCH v2 1/3] soundwire: qcom: add runtime pm support | From | Srinivas Kandagatla <> |
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On 24/02/2022 15:41, Pierre-Louis Bossart wrote: > >> static const struct snd_soc_dai_ops qcom_swrm_pdm_dai_ops = { >> @@ -1197,12 +1224,23 @@ static int qcom_swrm_get_port_config(struct qcom_swrm_ctrl *ctrl) >> static int swrm_reg_show(struct seq_file *s_file, void *data) >> { >> struct qcom_swrm_ctrl *swrm = s_file->private; >> - int reg, reg_val; >> + int reg, reg_val, ret; >> + >> + ret = pm_runtime_get_sync(swrm->dev); >> + if (ret < 0 && ret != -EACCES) { >> + dev_err_ratelimited(swrm->dev, >> + "pm_runtime_get_sync failed in %s, ret %d\n", >> + __func__, ret); >> + pm_runtime_put_noidle(swrm->dev); >> + } >> >> for (reg = 0; reg <= SWR_MSTR_MAX_REG_ADDR; reg += 4) { >> swrm->reg_read(swrm, reg, ®_val); >> seq_printf(s_file, "0x%.3x: 0x%.2x\n", reg, reg_val); >> } >> + pm_runtime_mark_last_busy(swrm->dev); >> + pm_runtime_put_autosuspend(swrm->dev); >> + > > question: is there a reason why this specific set of reg_read() is > surrounded pm_runtime stuff? Is this saying that in all other case where > the callback is used, the controller is already resumed and fully > operational? That's be worthy of a comment.
controller register reads require clk to be ON, which might not be always ON. In suspended case we switch off the clocks.
Other places so far that I have seen is that controller is either already resumed or clk is on (interrupt case) and resume case.
>> struct qcom_swrm_ctrl *swrm >> struct qcom_swrm_ctrl *ctrl > > nit-pick: it helps reviewers when the same variable name is used > consistently.
Yes, I did notice this, but for some reason I forgot to fix it.
> >> +static int __maybe_unused swrm_runtime_suspend(struct device *dev) >> +{ >> + struct qcom_swrm_ctrl *ctrl = dev_get_drvdata(dev); >> + int ret; >> + >> + if (!ctrl->clock_stop_not_supported) { >> + /* Mask bus clash interrupt */ >> + ctrl->intr_mask &= ~SWRM_INTERRUPT_STATUS_MASTER_CLASH_DET; >> + ctrl->reg_write(ctrl, SWRM_INTERRUPT_MASK_ADDR, ctrl->intr_mask); >> + ctrl->reg_write(ctrl, SWRM_INTERRUPT_CPU_EN, ctrl->intr_mask); >> + } >> + /* Prepare slaves for clock stop */ >> + ret = sdw_bus_prep_clk_stop(&ctrl->bus); >> + if (ret < 0) { > > if (ret < 0 && ret != -ENODATA) { > > ? > >> + dev_err(dev, "prepare clock stop failed %d", ret); >> + return ret; >> + } >> + >> + ret = sdw_bus_clk_stop(&ctrl->bus); >> + if (ret < 0 && ret != -ENODATA) { >> + dev_err(dev, "bus clock stop failed %d", ret); >> + return ret; >> + } >> + >> + clk_disable_unprepare(ctrl->hclk); >> + >> + usleep_range(300, 305); >> + >> + return 0; >> +}
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