Hello,
On Tue, 12 Dec 2023 19:51:46 +0800
Luo Jie <quic_luoj@xxxxxxxxxxx> wrote:
> The ethernet LDO provides the clock for the ethernet PHY that
> is connected with PCS, each LDO enables the clock output to
> each PCS, after the clock output enablement, the PHY GPIO reset
> can take effect.
>
> For the PHY taking the MDIO bus level GPIO reset, the ethernet
> LDO should be enabled before the MDIO bus register.
>
> For example, the qca8084 PHY takes the MDIO bus level GPIO
> reset for quad PHYs, there is another reason for qca8084 PHY
> using MDIO bus level GPIO reset instead of PHY level GPIO
> reset as below.
>
> The work sequence of qca8084:
> 1. enable ethernet LDO.
> 2. GPIO reset on quad PHYs.
> 3. register clock provider based on MDIO device of qca8084.
> 4. PHY probe function called for initializing common clocks.
> 5. PHY capabilities acquirement.
>
> If qca8084 takes PHY level GPIO reset in the step 4, the clock
> provider of qca8084 can't be registered correctly, since the
> clock parent(reading the current qca8084 hardware registers in
> step 3) of the registered clocks is deserted after GPIO reset.
>
> There are two PCS(UNIPHY) supported in SOC side on ipq5332,
> and three PCS(UNIPHY) supported on ipq9574.
>
> Signed-off-by: Luo Jie <quic_luoj@xxxxxxxxxxx>
> ---
[...]
> @@ -252,11 +244,32 @@ static int ipq4019_mdio_probe(struct platform_device *pdev)
> if (IS_ERR(priv->mdio_clk))
> return PTR_ERR(priv->mdio_clk);
>
> - /* The platform resource is provided on the chipset IPQ5018 */
> - /* This resource is optional */
> - res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> - if (res)
> - priv->eth_ldo_rdy = devm_ioremap_resource(&pdev->dev, res);
> + /* These platform resources are provided on the chipset IPQ5018 or
> + * IPQ5332.
> + */
> + /* This resource are optional */
> + for (index = 0; index < ETH_LDO_RDY_CNT; index++) {
> + res = platform_get_resource(pdev, IORESOURCE_MEM, index + 1);
> + if (res) {
> + priv->eth_ldo_rdy[index] = devm_ioremap(&pdev->dev,
> + res->start,
> + resource_size(res));
You can simplify that sequence by using
devm_platform_get_and_ioremap_resource(), which will do both the
platform_get_resource and the devm_ioremap at once for you.
Thanks,
Maxime
