Hi Pratyush,

On Tue 14 Dec 21, 23:37, Pratyush Yadav wrote:

Cosmetic suggestion: add whitespaces after { and before }.

+};
+
+static int cdns_dphy_rx_power_on(struct phy *phy)
+{
+	struct cdns_dphy_rx *dphy = phy_get_drvdata(phy);
+
+	/* Start RX state machine. */
+	writel(DPHY_CMN_SSM_EN | DPHY_CMN_RX_MODE_EN |
+	       FIELD_PREP(DPHY_CMN_RX_BANDGAP_TIMER_MASK,
+			  DPHY_CMN_RX_BANDGAP_TIMER),
+	       dphy->regs + DPHY_CMN_SSM);
+
+	return 0;
+}
+
+static int cdns_dphy_rx_power_off(struct phy *phy)
+{
+	struct cdns_dphy_rx *dphy = phy_get_drvdata(phy);
+
+	writel(0, dphy->regs + DPHY_CMN_SSM);
+
+	return 0;
+}
+
+static int cdns_dphy_rx_get_band_ctrl(unsigned long hs_clk_rate)
+{
+	unsigned int rate, i;
+
+	rate = hs_clk_rate / 1000000UL;
+	/* Since CSI-2 clock is DDR, the bit rate is twice the clock rate. */
+	rate *= 2;
+
+	if (rate < bands[0].min_rate)
+		return -EOPNOTSUPP;
+
+	for (i = 0; i < ARRAY_SIZE(bands); i++) {
+		if (rate < bands[i].max_rate)
+			return i;
+	}

Comstic: you don't need the wrapping { and } here.

+
+	return -EOPNOTSUPP;
+}
+
+static int cdns_dphy_rx_wait_for_bit(void __iomem *addr, unsigned int bit)

You can probably inline this one.

+{
+	u32 val;
+
+	return readl_relaxed_poll_timeout(addr, val, val & BIT(bit), 10,
+					  DPHY_ISO_LANE_READY_TIMEOUT_MS * 1000);
+}
+
+static int cdns_dphy_rx_wait_lane_ready(struct cdns_dphy_rx *dphy,
+					unsigned int lanes)
+{
+	static const u32 data_lane_ctrl[] = {DPHY_ISO_DL_CTRL_L0,
+					     DPHY_ISO_DL_CTRL_L1,
+					     DPHY_ISO_DL_CTRL_L2,
+					     DPHY_ISO_DL_CTRL_L3};
+	void __iomem *reg = dphy->regs;
+	unsigned int i;
+	int ret;
+
+	/* Data lanes. Minimum one lane is mandatory. */
+	if (lanes < DPHY_LANES_MIN || lanes > DPHY_LANES_MAX)
+		return -EINVAL;
+
+	/* Clock lane */
+	ret = cdns_dphy_rx_wait_for_bit(reg + DPHY_ISO_CL_CTRL_L,
+					DPHY_ISO_LANE_READY_BIT);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < lanes; i++) {
+		ret = cdns_dphy_rx_wait_for_bit(reg + data_lane_ctrl[i],
+						DPHY_ISO_LANE_READY_BIT);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int cdns_dphy_rx_configure(struct phy *phy,
+				  union phy_configure_opts *opts)
+{
+	struct cdns_dphy_rx *dphy = phy_get_drvdata(phy);
+	unsigned int reg;
+	int band_ctrl, ret;
+
+	band_ctrl = cdns_dphy_rx_get_band_ctrl(opts->mipi_dphy.hs_clk_rate);
+	if (band_ctrl < 0)
+		return band_ctrl;
+
+	reg = FIELD_PREP(DPHY_BAND_CFG_LEFT_BAND, band_ctrl) |
+	      FIELD_PREP(DPHY_BAND_CFG_RIGHT_BAND, band_ctrl);
+	writel(reg, dphy->regs + DPHY_BAND_CFG);
+
+	/*
+	 * Set the required power island phase 2 time. This is mandated by DPHY
+	 * specs.
+	 */
+	reg = DPHY_POWER_ISLAND_EN_DATA_VAL;
+	writel(reg, dphy->regs + DPHY_POWER_ISLAND_EN_DATA);
+	reg = DPHY_POWER_ISLAND_EN_CLK_VAL;
+	writel(reg, dphy->regs + DPHY_POWER_ISLAND_EN_CLK);
+
+	ret = cdns_dphy_rx_wait_lane_ready(dphy, opts->mipi_dphy.lanes);
+	if (ret) {
+		dev_err(dphy->dev, "DPHY wait for lane ready timeout\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int cdns_dphy_rx_validate(struct phy *phy, enum phy_mode mode,
+				 int submode, union phy_configure_opts *opts)
+{
+	int ret;
+
+	if (mode != PHY_MODE_MIPI_DPHY)
+		return -EINVAL;
+
+	ret = cdns_dphy_rx_get_band_ctrl(opts->mipi_dphy.hs_clk_rate);
+	if (ret < 0)
+		return ret;
+
+	return phy_mipi_dphy_config_validate(&opts->mipi_dphy);
+}
+
+static const struct phy_ops cdns_dphy_rx_ops = {
+	.power_on = cdns_dphy_rx_power_on,
+	.power_off = cdns_dphy_rx_power_off,
+	.configure = cdns_dphy_rx_configure,
+	.validate = cdns_dphy_rx_validate,
+};
+
+static int cdns_dphy_rx_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct phy_provider *provider;
+	struct cdns_dphy_rx *dphy;
+
+	dphy = devm_kzalloc(dev, sizeof(*dphy), GFP_KERNEL);
+	if (!dphy)
+		return -ENOMEM;
+
+	dev_set_drvdata(dev, dphy);

It looks like you're never getting the dphy pointer from dev so this seems a bit
pointless.

+	dphy->dev = dev;
+
+	dphy->regs = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(dphy->regs))
+		return PTR_ERR(dphy->regs);
+
+	dphy->phy = devm_phy_create(dev, NULL, &cdns_dphy_rx_ops);
+	if (IS_ERR(dphy->phy)) {
+		dev_err(dev, "Failed to create PHY: %d\n", PTR_ERR(dphy->phy));
+		return PTR_ERR(dphy->phy);
+	}
+
+	phy_set_drvdata(dphy->phy, dphy);
+	provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);

You might want to print an error message if it failed to register.

+
+	return PTR_ERR_OR_ZERO(provider);
+}
+
+static const struct of_device_id cdns_dphy_rx_of_match[] = {
+	{ .compatible = "cdns,dphy-rx" },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, cdns_dphy_rx_of_match);
+
+static struct platform_driver cdns_dphy_rx_platform_driver = {
+	.probe		= cdns_dphy_rx_probe,
+	.driver		= {
+		.name		= "cdns-mipi-dphy-rx",
+		.of_match_table	= cdns_dphy_rx_of_match,
+	},
+};
+module_platform_driver(cdns_dphy_rx_platform_driver);
+
+MODULE_AUTHOR("Pratyush Yadav [off-list ref]");
+MODULE_DESCRIPTION("Cadence D-PHY Rx Driver");
+MODULE_LICENSE("GPL v2");

Otherwise this looks good to me!

Cheers,

Paul

-- 
Paul Kocialkowski, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com