Hi,
Please refer to the comments below.
On 10/24/2013 05:52 PM, Kishon Vijay Abraham I wrote:
> Hi,
>
> On Monday 21 October 2013 07:48 PM, Tomasz Stanislawski wrote:
>> Add simple-phy driver to support a single register
>> PHY interfaces present on Exynos4 SoC.
>
> How are these PHY interfaces modelled in the SoC? Where does the register
> actually reside?
Initially, I was planning to add PHY for HDMI_PHY register in
power management register set on s5pv310 soc.
However other PHYs use very similar interface (setting bit 0).
This includes DAC_PHY, ADC_PHY, PCIe_PHY, SATA_PHY.
Moreover it suits well to USBDEVICE_PHY, USBHOST_PHY.
That is why I thought about using something more generic
to handle all those phys without introducing a herd of
200-lines-long drivers.
>>
>> Signed-off-by: Tomasz Stanislawski <t.stanislaws@xxxxxxxxxxx>
>> ---
>> drivers/phy/Kconfig | 5 ++
>> drivers/phy/Makefile | 1 +
>> drivers/phy/phy-simple.c | 128 ++++++++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 134 insertions(+)
>> create mode 100644 drivers/phy/phy-simple.c
>>
>> diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
>> index ac239ac..619c657 100644
>> --- a/drivers/phy/Kconfig
>> +++ b/drivers/phy/Kconfig
>> @@ -38,4 +38,9 @@ config TWL4030_USB
>> This transceiver supports high and full speed devices plus,
>> in host mode, low speed.
>>
>> +config PHY_SIMPLE
>> + tristate "Simple PHY driver"
>
> This is too generic a name to be used. Lets name it something specific to what
> it is used for (EXYNOS/HDMI.. ?).
Ok. It could be renamed to EXYNOS-SIMPLE-PHY or EXYNOS-1BIT-PHY or EXYNOS-GENERIC-PHY
or something similar. Any ideas?
>> + help
>> + Support for PHY controllers configured using single register.
>> +
>> endmenu
>> diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
>> index 0dd8a98..3d68e19 100644
>> --- a/drivers/phy/Makefile
>> +++ b/drivers/phy/Makefile
>> @@ -5,3 +5,4 @@
>> obj-$(CONFIG_GENERIC_PHY) += phy-core.o
>> obj-$(CONFIG_OMAP_USB2) += phy-omap-usb2.o
>> obj-$(CONFIG_TWL4030_USB) += phy-twl4030-usb.o
>> +obj-$(CONFIG_PHY_SIMPLE) += phy-simple.o
>> diff --git a/drivers/phy/phy-simple.c b/drivers/phy/phy-simple.c
>> new file mode 100644
>> index 0000000..4a28af7
>> --- /dev/null
>> +++ b/drivers/phy/phy-simple.c
>> @@ -0,0 +1,128 @@
>> +/*
>> + * Simple PHY driver
>> + *
>> + * Copyright (C) 2013 Samsung Electronics Co., Ltd.
>> + * Author: Tomasz Stanislawski <t.stanislaws@xxxxxxxxxxx>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + */
>> +
>> +#include <linux/io.h>
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/of_address.h>
>> +#include <linux/phy/phy.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/spinlock.h>
>> +
>> +struct simple_phy {
>> + spinlock_t slock;
>> + u32 on_value;
>> + u32 off_value;
>> + u32 mask;
>> + void __iomem *regs;
>> +};
>> +
>> +static int sphy_set(struct simple_phy *sphy, bool on)
>> +{
>> + u32 reg;
>> +
>> + spin_lock(&sphy->slock);
>
> Lets add spin_lock only when it is absolutely necessary. When your PHY provider
> implements only a single PHY, it is not needed. phy_power_on and phy_power_off
> is already protected by the framework.
ok
>> +
>> + reg = readl(sphy->regs);
>> + reg &= ~sphy->mask;
>> + reg |= sphy->mask & (on ? sphy->on_value : sphy->off_value);
>> + writel(reg, sphy->regs);
>> +
>> + spin_unlock(&sphy->slock);
>> +
>> + return 0;
>> +}
>> +
>> +static int simple_phy_power_on(struct phy *phy)
>> +{
>> + return sphy_set(phy_get_drvdata(phy), 1);
>> +}
>> +
>> +static int simple_phy_power_off(struct phy *phy)
>> +{
>> + return sphy_set(phy_get_drvdata(phy), 0);
>> +}
>> +
>> +static struct phy_ops simple_phy_ops = {
>> + .power_on = simple_phy_power_on,
>> + .power_off = simple_phy_power_off,
>> + .owner = THIS_MODULE,
>> +};
>> +
>> +static int simple_phy_probe(struct platform_device *pdev)
>> +{
>> + struct device *dev = &pdev->dev;
>> + struct simple_phy *sphy;
>> + struct resource *res;
>> + struct phy_provider *phy_provider;
>> + struct phy *phy;
>> +
>> + sphy = devm_kzalloc(dev, sizeof(*sphy), GFP_KERNEL);
>> + if (!sphy)
>> + return -ENOMEM;
>> +
>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +
>> + sphy->regs = devm_ioremap_resource(dev, res);
>> + if (IS_ERR(sphy->regs)) {
>> + dev_err(dev, "failed to ioremap registers\n");
>> + return PTR_ERR(sphy->regs);
>> + }
>> +
>> + spin_lock_init(&sphy->slock);
>> +
>> + phy_provider = devm_of_phy_provider_register(dev, NULL);
>
> pass 'of_phy_simple_xlate' instead of NULL.
>> + if (IS_ERR(phy_provider)) {
>> + dev_err(dev, "failed to register PHY provider\n");
>> + return PTR_ERR(phy_provider);
>> + }
>> +
>> + phy = devm_phy_create(dev, &simple_phy_ops, NULL);
>> + if (IS_ERR(phy)) {
>> + dev_err(dev, "failed to create PHY\n");
>> + return PTR_ERR(phy);
>> + }
>> +
>> + sphy->mask = 1;
>> + sphy->on_value = ~0;
>> + sphy->off_value = 0;
>> +
>> + of_property_read_u32(dev->of_node, "mask", &sphy->mask);
>
> This means your driver will depend on dt data to describe how the register
> should look like. Not a good idea.
I can remove it. No problem. The driver can justt use fixed
mask=1,on-value=1,off-value=0.
Adding mentioned attributes greatly improves driver flexibility
but such a flexibility is not needed currently for s5pv310 phys.
But frankly, I do not exactly follow what is a rationale for such police
in DT. It forces developer to write a lot of redundant code.
Moreover, some clock drivers seams to violate it.
Clock "picochip,pc3x3-gated-clk" is an example. One can find similar tricks
in pinctrl.
>> + of_property_read_u32(dev->of_node, "on-value", &sphy->on_value);
>> + of_property_read_u32(dev->of_node, "off-value", &sphy->off_value);
>> +
>> + phy_set_drvdata(phy, sphy);
>> +
>> + dev_info(dev, "probe successful\n");
> Lets not make the boot noisy.
>
ok. s/dev_info/dev_dbg is good enough?
> Thanks
> Kishon
>
Could you take a look on other patches in this RFC?
Regards,
Tomasz Stanislawski
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