Re: [PATCH v3 4/4] phy: qcom-qmp: new qmp phy driver for qcom-chipsets

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Hi,


On 01/06/2017 12:48 PM, Bjorn Andersson wrote:
On Tue 20 Dec 09:03 PST 2016, Vivek Gautam wrote:

diff --git a/drivers/phy/phy-qcom-qmp.c b/drivers/phy/phy-qcom-qmp.c
[..]
+static int qcom_qmp_phy_poweron(struct phy *phy)
[..]
+
+err3:
Rather than naming your labels errX, it's idiomatic to give them
descriptive names, e.g. "disable_ref_clk" here.
Sure will change these labels and any such occurrence further in the code.


+	clk_disable_unprepare(qphy->ref_clk);
+err2:
+	regulator_disable(qphy->vddp_ref_clk);
+err1:
+	regulator_disable(qphy->vdda_pll);
+err:
+	regulator_disable(qphy->vdda_phy);
+	return ret;
+}
[..]
+static int qcom_qmp_phy_com_init(struct qcom_qmp_phy *qphy)
+{
+	const struct qmp_phy_cfg *cfg = qphy->cfg;
+	void __iomem *serdes = qphy->serdes;
+	int ret;
+
+	mutex_lock(&qphy->phy_mutex);
+	if (qphy->init_count++) {
+		mutex_unlock(&qphy->phy_mutex);
+		return 0;
+	}
As far as I can see phy_init() and phy_exit() already keep reference
count on the initialization and you only call this function from
phy_ops->init, so you should be able to drop this.
This is an intermediary function that does the common block initialization.
PHYs like PCIe have a separate common block (apart from SerDes)
for all phy channels. We shouldn't program this common block
multiple times for each channel. That's why this init_count.


[..]
+
+/* PHY Initialization */
+static int qcom_qmp_phy_init(struct phy *phy)
+{
[..]
+	/* phy power down delay; given in PCIE phy programming guide only */
+	if (qphy->cfg->type == PHY_TYPE_PCIE)
Rather than basing this off "is this pcie" it's preferred if you have a
bool power_down_delay; (or optionally carrying the timeout value) to
control this.
Sure, will modify this.


+		usleep_range(POWER_DOWN_DELAY_US_MIN, POWER_DOWN_DELAY_US_MAX);
+
+	/* start SerDes and Phy-Coding-Sublayer */
+	qphy_setbits(pcs + QPHY_START_CTRL, cfg->start_ctrl);
+
+	/* Pull PHY out of reset state */
+	qphy_clrbits(pcs + QPHY_SW_RESET, SW_RESET);
+
+	status = pcs + cfg->regs[QPHY_PCS_READY_STATUS];
+	mask = cfg->mask_pcs_ready;
+
+	ret = !mask ? 0 : readl_poll_timeout(status, val, !(val & mask), 1,
+						PHY_INIT_COMPLETE_TIMEOUT);
I presume it's not okay to read the status register even once for pcie?
If it is you can skip the conditional as !(val & 0) will break the poll
after the first read.
Yea, it is okay to read the status register for pcie.

Will leave just readl_poll_timeout() that exits on !(val & mask).
We anyways don't set mask_pcs_ready for pcie.

[..]
+static int qcom_qmp_phy_exit(struct phy *phy)
+{
[..]
+}
+
+
Extra blank line
Will remove it.

+static int qcom_qmp_phy_regulator_init(struct device *dev)
[..]
+static
+struct qmp_phy_desc *qcom_qmp_phy_create(struct platform_device *pdev, int id)
+{
[..]
+	phy_desc->pipe_clk = devm_clk_get(dev, prop_name);
+	if (IS_ERR(phy_desc->pipe_clk)) {
+		if (qphy->cfg->type == PHY_TYPE_PCIE ||
+		    qphy->cfg->type == PHY_TYPE_USB3) {
Is this check adding any value?
The USB3 and PCIe phys are PIPE based phys, and hence the pipe
clock is mandatory for them. Other phys don't care about pipe clock.


+			ret = PTR_ERR(phy_desc->pipe_clk);
+			if (ret != -EPROBE_DEFER)
+				dev_err(dev,
+					"failed to get lane%d pipe_clk, %d\n",
+					id, ret);
+			return ERR_PTR(ret);
+		}
+		phy_desc->pipe_clk = NULL;
Regards,
Bjorn
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Regards
Vivek

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