Subject: [RFC][PATCH 1/2] ARM: OMAP4: clock: Add device tree support for AUXCLKs

From: [email-masked] (Roger Quadros)
Date: Wed, 10 Apr 2013 13:55:58 +0300

On 04/10/2013 11:06 AM, Mike Turquette wrote:
> Quoting Nishanth Menon (2013-04-09 13:49:00)
>> On 10:43-20130409, Tony Lindgren wrote:
>>> * Tony Lindgren <[email-masked]> [130409 09:54]:
>>>> * Roger Quadros <[email-masked]> [130409 03:00]:
>>>>> On 04/05/2013 06:58 PM, Tony Lindgren wrote:
>>>>>>
>>>>>> Can't you just use the clock name there to get it?
>>>>>
>>>>> In device tree we don't pass around clock names. You can either get
>>>>> a phandle or an index to the clock.
>>>>>
>>>>> e.g. Documentation/devicetree/bindings/clock/imx31-clock.txt
>>>>
>>>> Yes I understand that. But the driver/clock/omap driver can just
>>>> remap the DT device initially so the board specific clock is
>>>> found from the clock alias table. Basically initially a passthrough
>>>> driver that can be enhanced to parse DT clock bindings and load
>>>> data from /lib/firmware.
>>>
>>> Actually probably the driver/clock/omap can even do even less
>>> initially. There probably even no need to remap clocks there.
>>>
>>> As long as the DT clock driver understands that a board specific
>>> auxclk is specified in the DT it can just call clk_add_alias() so
>>> the driver will get the right auxclk from cclock44xx_data.c.
>>>
>>> Then other features can be added later on like to allocate a
>>> clock entirely based on the binding etc.
>> I did try to have an implementation for cpufreq using clock nodes.
>> unfortunately, device tree wont let me have arguments of strings :(
>> So, I am unable to do clock = <&clk mpu_dpll>;
>> instead, I am forced to do clock = <&clk 249>;
>>
> 
> See http://article.gmane.org/gmane.linux.ports.arm.kernel/229034
> 

Awesome. Thanks for pointing this out Mike.

Now all we need to do is create a named define for each clock index in the
header file.

cheers,
-roger

> 
>> Here is an attempt on beagleXM - adds every clock node to the list.
>> Tons of un-necessary prints added to give an idea - see log:
>> http://pastebin.com/F9A2zSTr
>>
>> Would an cleaned up version be good enough as a step #1 of transition?
>>
>> From 7d373bdb9e9549c1b6ba1775a8dfd96ebe78abfb Mon Sep 17 00:00:00 2001
>> From: Nishanth Menon <[email-masked]>
>> Date: Tue, 26 Mar 2013 10:23:27 +0000
>> Subject: [PATCH] OMAP: add devicetree support for clock nodes.
>>
>> Dummy patch based on Roger's original idea
>>
>> Nyet-Signed-off-by: Nishanth Menon <[email-masked]>
>> ---
>>  arch/arm/boot/dts/omap3.dtsi          |    5 ++
>>  arch/arm/boot/dts/omap34xx.dtsi       |    2 +
>>  arch/arm/mach-omap2/cclock3xxx_data.c |    3 +-
>>  arch/arm/mach-omap2/cclock44xx_data.c |    3 +-
>>  arch/arm/mach-omap2/pm.c              |   11 +++-
>>  drivers/clk/Kconfig                   |    6 ++
>>  drivers/clk/Makefile                  |    2 +
>>  drivers/clk/ti.c                      |  100 +++++++++++++++++++++++++++++++++
>>  include/linux/clk/ti.h                |   30 ++++++++++
>>  9 files changed, 157 insertions(+), 5 deletions(-)
>>  create mode 100644 drivers/clk/ti.c
>>  create mode 100644 include/linux/clk/ti.h
>>
>> diff --git a/arch/arm/boot/dts/omap3.dtsi b/arch/arm/boot/dts/omap3.dtsi
>> index 3344f05..a08990d 100644
>> --- a/arch/arm/boot/dts/omap3.dtsi
>> +++ b/arch/arm/boot/dts/omap3.dtsi
>> @@ -73,6 +73,11 @@
>>                         ti,hwmods = "counter_32k";
>>                 };
>>  
>> +               clks: clocks {
>> +                       compatible = "ti,clock";
>> +                       #clock-cells = <1>;
>> +               };
>> +
>>                 intc: interrupt-controller at 48200000 {
>>                         compatible = "ti,omap2-intc";
>>                         interrupt-controller;
>> diff --git a/arch/arm/boot/dts/omap34xx.dtsi b/arch/arm/boot/dts/omap34xx.dtsi
>> index 75ed4ae..93c2621 100644
>> --- a/arch/arm/boot/dts/omap34xx.dtsi
>> +++ b/arch/arm/boot/dts/omap34xx.dtsi
>> @@ -23,6 +23,8 @@
>>                                 600000  1350000
>>                         >;
>>                         clock-latency = <300000>; /* From legacy driver */
>> +                       clocks = <&clks 249>; /* index to cpufreq_ck */
>> +                       clock-names = "cpu";
>>                 };
>>         };
>>  };
>> diff --git a/arch/arm/mach-omap2/cclock3xxx_data.c b/arch/arm/mach-omap2/cclock3xxx_data.c
>> index 4579c3c..d5d5ef5 100644
>> --- a/arch/arm/mach-omap2/cclock3xxx_data.c
>> +++ b/arch/arm/mach-omap2/cclock3xxx_data.c
>> @@ -22,6 +22,7 @@
>>  #include <linux/clk-private.h>
>>  #include <linux/list.h>
>>  #include <linux/io.h>
>> +#include <linux/clk/ti.h>
>>  
>>  #include "soc.h"
>>  #include "iomap.h"
>> @@ -3574,7 +3575,7 @@ int __init omap3xxx_clk_init(void)
>>         for (c = omap3xxx_clks; c < omap3xxx_clks + ARRAY_SIZE(omap3xxx_clks);
>>              c++)
>>                 if (c->cpu & cpu_clkflg) {
>> -                       clkdev_add(&c->lk);
>> +                       ti_clk_node_add(&c->lk);
>>                         if (!__clk_init(NULL, c->lk.clk))
>>                                 omap2_init_clk_hw_omap_clocks(c->lk.clk);
>>                 }
>> diff --git a/arch/arm/mach-omap2/cclock44xx_data.c b/arch/arm/mach-omap2/cclock44xx_data.c
>> index 0c6834a..338ef64 100644
>> --- a/arch/arm/mach-omap2/cclock44xx_data.c
>> +++ b/arch/arm/mach-omap2/cclock44xx_data.c
>> @@ -27,6 +27,7 @@
>>  #include <linux/clk-private.h>
>>  #include <linux/clkdev.h>
>>  #include <linux/io.h>
>> +#include <linux/clk/ti.h>
>>  
>>  #include "soc.h"
>>  #include "iomap.h"
>> @@ -1697,7 +1698,7 @@ int __init omap4xxx_clk_init(void)
>>         for (c = omap44xx_clks; c < omap44xx_clks + ARRAY_SIZE(omap44xx_clks);
>>                                                                         c++) {
>>                 if (c->cpu & cpu_clkflg) {
>> -                       clkdev_add(&c->lk);
>> +                       ti_clk_node_add(&c->lk);
>>                         if (!__clk_init(NULL, c->lk.clk))
>>                                 omap2_init_clk_hw_omap_clocks(c->lk.clk);
>>                 }
>> diff --git a/arch/arm/mach-omap2/pm.c b/arch/arm/mach-omap2/pm.c
>> index 8d15f9a..6cf95160 100644
>> --- a/arch/arm/mach-omap2/pm.c
>> +++ b/arch/arm/mach-omap2/pm.c
>> @@ -267,7 +267,12 @@ static void __init omap4_init_voltages(void)
>>  
>>  static inline void omap_init_cpufreq(void)
>>  {
>> -       struct platform_device_info devinfo = { .name = "omap-cpufreq", };
>> +       struct platform_device_info devinfo = { };
>> +
>> +       if (!of_have_populated_dt())
>> +               devinfo.name = "omap-cpufreq";
>> +       else
>> +               devinfo.name = "cpufreq-cpu0";
>>         platform_device_register_full(&devinfo);
>>  }
>>  
>> @@ -301,9 +306,9 @@ int __init omap2_common_pm_late_init(void)
>>                 /* Smartreflex device init */
>>                 omap_devinit_smartreflex();
>>  
>> -               /* cpufreq dummy device instantiation */
>> -               omap_init_cpufreq();
>>         }
>> +       /* cpufreq dummy device instantiation */
>> +       omap_init_cpufreq();
>>  
>>  #ifdef CONFIG_SUSPEND
>>         suspend_set_ops(&omap_pm_ops);
>> diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
>> index a47e6ee..03c6e48 100644
>> --- a/drivers/clk/Kconfig
>> +++ b/drivers/clk/Kconfig
>> @@ -55,6 +55,12 @@ config COMMON_CLK_MAX77686
>>         ---help---
>>           This driver supports Maxim 77686 crystal oscillator clock. 
>>  
>> +config COMMON_CLK_TI
>> +       tristate "Clock driver for TI SoCs"
>> +       depends on ARCH_OMAP && OF
>> +       ---help---
>> +         Fill me up.. some generic statement ofcourse (lets start with OMAP)
>> +
>>  config CLK_TWL6040
>>         tristate "External McPDM functional clock from twl6040"
>>         depends on TWL6040_CORE
>> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
>> index 300d477..9621815 100644
>> --- a/drivers/clk/Makefile
>> +++ b/drivers/clk/Makefile
>> @@ -30,6 +30,8 @@ obj-$(CONFIG_ARCH_TEGRA)      += tegra/
>>  
>>  obj-$(CONFIG_X86)              += x86/
>>  
>> +obj-$(CONFIG_COMMON_CLK_TI)    += ti.o
>> +
>>  # Chip specific
>>  obj-$(CONFIG_COMMON_CLK_WM831X) += clk-wm831x.o
>>  obj-$(CONFIG_COMMON_CLK_MAX77686) += clk-max77686.o
>> diff --git a/drivers/clk/ti.c b/drivers/clk/ti.c
>> new file mode 100644
>> index 0000000..c747381
>> --- /dev/null
>> +++ b/drivers/clk/ti.c
>> @@ -0,0 +1,100 @@
>> +/*
>> + * TI Clock node provider
>> + *
>> + * Copyright (C) 2013 Texas Instruments Incorporated - http://www.ti.com/
>> + *     Nishanth Menon
>> + *
>> + * 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.
>> + *
>> + * This program is distributed "as is" WITHOUT ANY WARRANTY of any
>> + * kind, whether express or implied; without even the implied warranty
>> + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + */
>> +#include <linux/kernel.h>
>> +#include <linux/list.h>
>> +#include <linux/clk-private.h>
>> +#include <linux/clkdev.h>
>> +#include <linux/io.h>
>> +#include <linux/of.h>
>> +#include <linux/clk/ti.h>
>> +
>> +struct ti_clk {
>> +       struct clk_lookup *lk;
>> +       struct list_head node;
>> +};
>> +
>> +static LIST_HEAD(ti_clk_list);
>> +
>> +static struct clk *ti_bypass_clk_get_by_name(struct of_phandle_args *clkspec,
>> +                                            void *data)
>> +{
>> +       struct ti_clk *c;
>> +#if 0
>> +       /* Eww.. IF ONLY phandle arguments could be string */
>> +       char clk_name[32]; /* 32 is max size of property name */
>> +
>> +       char *name = clkspec->args[0];
>> +
>> +       snprintf(clk_name, 32, "%s_ck", name);
>> +       list_for_each_entry(c, &ti_clk_list, node) {
>> +               int r = strncmp(c->lk->conn_id, clk_name, 32);
>> +               pr_err("%s: searching %s in %s - %d\n",
>> +                       __func__, clk_name, c->lk->con_id, r);
>> +               if (!r) {
>> +                       pr_err("%s: found it!\n", __func__);
>> +                       return c->lk.clk;
>> +               }
>> +       }
>> +#else
>> +       /* Use integer indexing into clkdev list! Sigh.. */
>> +       int idx = clkspec->args[0];
>> +       int cindex = 1;
>> +
>> +       list_for_each_entry(c, &ti_clk_list, node) {
>> +               int r = (idx == cindex) ? 0 :  1;
>> +               pr_err("%s: searching index search = %d in %d in %s - %d\n",
>> +                       __func__, idx, cindex, c->lk->con_id, r);
>> +               if (!r) {
>> +                       pr_err("%s: found it!\n", __func__);
>> +                       return c->lk->clk;
>> +               }
>> +               cindex++;
>> +       }
>> +#endif
>> +
>> +       pr_err("%s: ran out of options\n", __func__);
>> +       return ERR_PTR(-ENODEV);
>> +}
>> +
>> +static void __init ti_clock_init(struct device_node *node)
>> +{
>> +
>> +       pr_err("%s: START\n", __func__);
>> +       of_clk_add_provider(node, ti_bypass_clk_get_by_name, NULL);
>> +       pr_err("%s: END\n", __func__);
>> +}
>> +CLK_OF_DECLARE(ti_clk, "ti,clock", ti_clock_init);
>> +
>> +void __init ti_clk_node_add(struct clk_lookup *lk)
>> +{
>> +       struct ti_clk *c;
>> +       static bool of_added;
>> +
>> +       c = kzalloc(sizeof(struct ti_clk), GFP_KERNEL);
>> +       if (!c) {
>> +               pr_err("%s: No memory!! cannot add clk node!\n", __func__);
>> +               return;
>> +       }
>> +       clkdev_add(lk);
>> +       c->lk = lk;
>> +       list_add_tail(&c->node, &ti_clk_list);
>> +       pr_err("%s: Added clock node %s\n", __func__, lk->con_id);
>> +       if (!of_added) {
>> +               of_clk_init(NULL);
>> +               of_added =  true;
>> +       }
>> +};
>> +
>> diff --git a/include/linux/clk/ti.h b/include/linux/clk/ti.h
>> new file mode 100644
>> index 0000000..eb502a8
>> --- /dev/null
>> +++ b/include/linux/clk/ti.h
>> @@ -0,0 +1,30 @@
>> +/*
>> + * TI Clock node provider header
>> + *
>> + * Copyright (C) 2013 Texas Instruments Incorporated - http://www.ti.com/
>> + *     Nishanth Menon
>> + *
>> + * 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.
>> + *
>> + * This program is distributed "as is" WITHOUT ANY WARRANTY of any
>> + * kind, whether express or implied; without even the implied warranty
>> + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + */
>> +#ifndef __TI_CLK_H
>> +#define __TI_CLK_H
>> +
>> +#include <linux/clkdev.h>
>> +
>> +#ifdef CONFIG_OF
>> +extern void ti_clk_node_add(struct clk_lookup *lk);
>> +#else
>> +static inline void ti_clk_node_add(struct clk_lookup *lk)
>> +{
>> +       clkdev_add(lk);
>> +}
>> +#endif /* CONFIG_OF */
>> +
>> +#endif /* __TI_CLK_H */
>> -- 
>> 1.7.9.5
>>
>>
>> -- 
>> Regards,
>> Nishanth Menon
>> --
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