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SubjectRe: [PATCH V4 1/5] phy: Add new Exynos5 USB 3.0 PHY driver
From
Hi,


On Wed, Apr 9, 2014 at 4:36 PM, Tomasz Figa <t.figa@samsung.com> wrote:
> Hi Vivek,
>
> Please see my comments inline.
>
>
> On 08.04.2014 16:36, Vivek Gautam wrote:
>>
>> Add a new driver for the USB 3.0 PHY on Exynos5 series of SoCs.
>> The new driver uses the generic PHY framework and will interact
>> with DWC3 controller present on Exynos5 series of SoCs.
>> Thereby, removing old phy-samsung-usb3 driver and related code
>> used untill now which was based on usb/phy framework.
>>
>> Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
>> ---
>> .../devicetree/bindings/phy/samsung-phy.txt | 42 ++
>> drivers/phy/Kconfig | 11 +
>> drivers/phy/Makefile | 1 +
>> drivers/phy/phy-exynos5-usbdrd.c | 668
>> ++++++++++++++++++++
>> 4 files changed, 722 insertions(+)
>> create mode 100644 drivers/phy/phy-exynos5-usbdrd.c
>
>
> [snip]
>
>
>> + Additional clock required for Exynos5420:
>> + - usb30_sclk_100m: Additional special clock used for PHY operation
>> + depicted as 'sclk_usbphy30' in CMU of
>> Exynos5420.
>
>
> Are you sure this isn't simply a gate for the ref clock, as it can be found
> on another SoC that is not upstream yet? I don't have documentation for
> Exynos 5420 so I can't tell, but I'd like to ask you to recheck this.

From what i can see in the manual :
sclk_usbphy30 is derived from OSCCLK.
It is coming from a MUX (default input line to this is OSCCLK) and
then through a DIV
there's this gate.

{OSCCLK + other sources} --->[MUX] ---> [DIV] --> [GATE for
sclk_usbphy30]

the {rate of sclk_usbphy30} == OSCCLK

However the 'ref' clock that we have been using is the actual oscillator clock.
And on SoC Exynos5250, we don't have any such gate (sclk_usbphy30).
So should this mean that ref clock and sclk_usbphy30 are still be controlled by
two different gates ?

>
>
>> +- samsung,syscon-phandle: phandle for syscon interface, which is used to
>> + control pmu registers for power isolation.
>> +- samsung,pmu-offset: phy power control register offset to
>> pmu-system-controller
>> + base.
>> +- #phy-cells : from the generic PHY bindings, must be 1;
>> +
>> +For "samsung,exynos5250-usbdrd-phy" and "samsung,exynos5420-usbdrd-phy"
>> +compatible PHYs, the second cell in the PHY specifier identifies the
>> +PHY id, which is interpreted as follows:
>> + 0 - UTMI+ type phy,
>> + 1 - PIPE3 type phy,
>> +
>> +Example:
>> + usb3_phy: usbphy@12100000 {
>> + compatible = "samsung,exynos5250-usbdrd-phy";
>> + reg = <0x12100000 0x100>;
>> + clocks = <&clock 286>, <&clock 1>;
>> + clock-names = "phy", "usb3phy_refclk";
>
>
> Binding description above doesn't mention "usb3phy_refclk" entry.

my bad !! will correct this.

>
>
>> + samsung,syscon-phandle = <&pmu_syscon>;
>> + samsung,pmu-offset = <0x704>;
>> + #phy-cells = <1>;
>> + };
>
>
> [snip]
>
>
>> diff --git a/drivers/phy/phy-exynos5-usbdrd.c
>> b/drivers/phy/phy-exynos5-usbdrd.c
>> new file mode 100644
>> index 0000000..ff54a7c
>> --- /dev/null
>> +++ b/drivers/phy/phy-exynos5-usbdrd.c
>
>
> [snip]
>
>
>> +static int exynos5_usbdrd_phy_probe(struct platform_device *pdev)
>> +{
>> + struct device *dev = &pdev->dev;
>> + struct device_node *node = dev->of_node;
>> + struct exynos5_usbdrd_phy *phy_drd;
>> + struct phy_provider *phy_provider;
>> + struct resource *res;
>> + const struct of_device_id *match;
>> + const struct exynos5_usbdrd_phy_drvdata *drv_data;
>> + struct regmap *reg_pmu;
>> + u32 pmu_offset;
>> + int i;
>> +
>> + /*
>> + * Exynos systems are completely DT enabled,
>> + * so lets not have any platform data support for this driver.
>> + */
>> + if (!node) {
>> + dev_err(dev, "no device node found\n");
>
>
> This error message is not very meaningful. I'd rather use something like
> "This driver can be only instantiated using Device Tree".

Sure, will amend this.

>
>
>> + return -ENODEV;
>> + }
>> +
>> + match = of_match_node(exynos5_usbdrd_phy_of_match,
>> pdev->dev.of_node);
>> + if (!match) {
>> + dev_err(dev, "of_match_node() failed\n");
>> + return -EINVAL;
>> + }
>> + drv_data = match->data;
>> +
>> + phy_drd = devm_kzalloc(dev, sizeof(*phy_drd), GFP_KERNEL);
>> + if (!phy_drd)
>> + return -ENOMEM;
>> +
>> + dev_set_drvdata(dev, phy_drd);
>> + phy_drd->dev = dev;
>> +
>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> + phy_drd->reg_phy = devm_ioremap_resource(dev, res);
>> + if (IS_ERR(phy_drd->reg_phy)) {
>> + dev_err(dev, "Failed to map register memory (phy)\n");
>
>
> devm_ioremap_resource() already prints an error message.
Ok, will remove this message.

>
> Best regards,
> Tomasz
> --
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