RE: [EXT] Re: [v2 2/3] clk: ls1028a: Add clock driver for Display output interface

[Wen He]

> -----Original Message-----
> From: Stephen Boyd <sboyd@xxxxxxxxxx>
> Sent: 2019å8æ17æ 1:46
> To: Mark Rutland <mark.rutland@xxxxxxx>; Michael Turquette
> <mturquette@xxxxxxxxxxxx>; Rob Herring <robh+dt@xxxxxxxxxx>; Shawn Guo
> <shawnguo@xxxxxxxxxx>; Wen He <wen.he_1@xxxxxxx>;
> devicetree@xxxxxxxxxxxxxxx; linux-clk@xxxxxxxxxxxxxxx;
> linux-devel@xxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Cc: Leo Li <leoyang.li@xxxxxxx>; liviu.dudau@xxxxxxx; Wen He
> <wen.he_1@xxxxxxx>
> Subject: [EXT] Re: [v2 2/3] clk: ls1028a: Add clock driver for Display output
> interface
> 
> Caution: EXT Email
> 
> Quoting Wen He (2019-08-15 03:16:12)
> > diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig index
> > 801fa1cd0321..3c95d8ec31d4 100644
> > --- a/drivers/clk/Kconfig
> > +++ b/drivers/clk/Kconfig
> > @@ -223,6 +223,16 @@ config CLK_QORIQ
> >           This adds the clock driver support for Freescale QorIQ platforms
> >           using common clock framework.
> >
> > +config CLK_LS1028A_PLLDIG
> > +        bool "Clock driver for LS1028A Display output"
> > +       depends on (ARCH_LAYERSCAPE || COMPILE_TEST) && OF
> 
> Where is the OF dependency to build anything? Doesn't this still compile
> without CONFIG_OF set?

Yes, current included some APIs of the OF, like of_get_parent_name()

> 
> > +       default ARCH_LAYERSCAPE
> > +        help
> > +          This driver support the Display output interfaces(LCD, DPHY)
> pixel clocks
> > +          of the QorIQ Layerscape LS1028A, as implemented TSMC
> CLN28HPM PLL. Not all
> > +          features of the PLL are currently supported by the driver. By
> default,
> > +          configured bypass mode with this PLL.
> 
> These lines look sort of long. Are they under 80 columns?
> 

Yes, they had been checked by the checkpatch.pl. 

> > +
> >  config COMMON_CLK_XGENE
> >         bool "Clock driver for APM XGene SoC"
> >         default ARCH_XGENE
> > diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile index
> > 0cad76021297..c8e22a764c4d 100644
> > --- a/drivers/clk/Makefile
> > +++ b/drivers/clk/Makefile
> > @@ -44,6 +44,7 @@ obj-$(CONFIG_COMMON_CLK_OXNAS)
> += clk-oxnas.o
> >  obj-$(CONFIG_COMMON_CLK_PALMAS)                += clk-palmas.o
> >  obj-$(CONFIG_COMMON_CLK_PWM)           += clk-pwm.o
> >  obj-$(CONFIG_CLK_QORIQ)                        += clk-qoriq.o
> > +obj-$(CONFIG_CLK_LS1028A_PLLDIG)       += clk-plldig.o
> >  obj-$(CONFIG_COMMON_CLK_RK808)         += clk-rk808.o
> >  obj-$(CONFIG_COMMON_CLK_HI655X)                += clk-hi655x.o
> >  obj-$(CONFIG_COMMON_CLK_S2MPS11)       += clk-s2mps11.o
> > diff --git a/drivers/clk/clk-plldig.c b/drivers/clk/clk-plldig.c new
> > file mode 100644 index 000000000000..60988b0ea20a
> > --- /dev/null
> > +++ b/drivers/clk/clk-plldig.c
> > @@ -0,0 +1,278 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +// Copyright 2019 NXP
> > +
> > +/*
> > + * Clock driver for LS1028A Display output interfaces(LCD, DPHY).
> > + */
> > +
> > +#include <linux/clk-provider.h>
> > +#include <linux/device.h>
> > +#include <linux/module.h>
> > +#include <linux/err.h>
> > +#include <linux/io.h>
> > +#include <linux/iopoll.h>
> > +#include <linux/of.h>
> [...]
> > +
> > +static int plldig_clk_probe(struct platform_device *pdev) {
> > +       struct clk_plldig *data;
> > +       struct resource *mem;
> > +       const char *parent_name;
> > +       struct clk_init_data init = {};
> > +       struct device *dev = &pdev->dev;
> > +       int ret;
> > +
> > +       data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> > +       if (!data)
> > +               return -ENOMEM;
> > +
> > +       mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > +       data->regs = devm_ioremap_resource(dev, mem);
> > +       if (IS_ERR(data->regs))
> > +               return PTR_ERR(data->regs);
> > +
> > +       init.name = dev->of_node->name;
> > +       init.ops = &plldig_clk_ops;
> > +       parent_name = of_clk_get_parent_name(dev->of_node, 0);
> > +       init.parent_names = &parent_name;
> 
> Can you use the new way of specifying clk parents with the parent_data
> member of clk_init?

Of course, but I don't understand why need recommend to use this member?
Is that the member parent_names will be discard in future?

Here are definition of the clk-provider.h
/* Only one of the following three should be assigned */
const char              * const *parent_names;
const struct clk_parent_data    *parent_data;
const struct clk_hw             **parent_hws;

For PLLDIG, it only has one parent.


> 
> > +       init.num_parents = 1;
> > +
> > +       data->hw.init = &init;
> > +       data->dev = dev;
> > +
> > +       ret = devm_clk_hw_register(dev, &data->hw);
> > +       if (ret) {
> > +               dev_err(dev, "failed to register %s clock\n", init.name);
> > +               return ret;
> > +       }
> > +
> > +       return of_clk_add_hw_provider(dev->of_node,
> > + of_clk_hw_simple_get,
> 
> Use devm? So that driver remove frees this.

Yes, here also should be using devm_of_clk_add_hw_provider().

> 
> > +                       &data->hw);
> > +}
> > +
> > +static int plldig_clk_remove(struct platform_device *pdev) {
> > +       of_clk_del_provider(pdev->dev.of_node);
> > +       return 0;
> > +}
> > +
> > +static const struct of_device_id plldig_clk_id[] = {
> > +       { .compatible = "fsl,ls1028a-plldig", .data = NULL},
> > +       { }
> > +};
> 
> Add a MODULE_DEVICE_TABLE(of, plldig_clk_id) here.
> 
OK,

> > +
> > +static struct platform_driver plldig_clk_driver = {
> > +       .driver = {
> > +               .name = "plldig-clock",
> > +               .of_match_table = plldig_clk_id,
> > +       },
> > +       .probe = plldig_clk_probe,
> > +       .remove = plldig_clk_remove,
> > +};
> > +module_platform_driver(plldig_clk_driver);
> > +
> > +MODULE_LICENSE("GPL v2");
> > +MODULE_AUTHOR("Wen He <wen.he_1@xxxxxxx>");
> > +MODULE_DESCRIPTION("LS1028A Display output interface pixel clock
> > +driver"); MODULE_ALIAS("platform:ls1028a-plldig");
> 
> Drop MODULE_ALIAS, it's not useful.

OK, 

Best Regards,
Wen