[PATCH V6] ARM: bcm2835: add stub clock driver

[PATCH V6] ARM: bcm2835: add stub clock driver

[Stephen Warren]

From: Simon Arlott <simon@fire.lp0.eu>

This patch adds a minimal stub clock driver for the BCM2835. Its sole
purpose is to allow the PL011 AMBA clk_get() API calls to provide
something that looks enough like a clock that the driver probes and
operates correctly.

This patch was extracted from git://github.com/lp0/linux.git branch
rpi-split as of 2012/09/08, and modified as follows:

* Reworked to call clk_register_fixed_rate(), and clk_register_clkdev()
  rather than using static data to represent the clocks.
* Moved implementation to drivers/clk/.
* Modified .dev_id for UART clocks to match UART DT node names.
* s/bcm2708/bcm2835/.
* Modified device tree vendor prefix.

Signed-off-by: Chris Boot <bootc@bootc.net>
Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
Signed-off-by: Dom Cobley <popcornmix@gmail.com>
Signed-off-by: Dom Cobley <dc4@broadcom.com>
Cc: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
--
v6:
* Reworked to call clk_register_fixed_rate(), and clk_register_clkdev()
  rather than using static data to represent the clocks.
v5:
* No change.
v4:
* Moved implementation to drivers/clk/.
* s/bcm2708/bcm2835/.
* Updated for new device tree vendor prefix.
v3:
* New patch.

clk fixup
---
 arch/arm/mach-bcm2835/bcm2835.c |    3 ++
 drivers/clk/Makefile            |    1 +
 drivers/clk/clk-bcm2835.c       |   58 +++++++++++++++++++++++++++++++++++++++
 include/linux/clk/bcm2835.h     |   24 ++++++++++++++++
 4 files changed, 86 insertions(+)
 create mode 100644 drivers/clk/clk-bcm2835.c
 create mode 100644 include/linux/clk/bcm2835.h

diff --git a/arch/arm/mach-bcm2835/bcm2835.c b/arch/arm/mach-bcm2835/bcm2835.c
index e3f2968..f6fea49 100644
--- a/arch/arm/mach-bcm2835/bcm2835.c
+++ b/arch/arm/mach-bcm2835/bcm2835.c
@@ -16,6 +16,7 @@
 #include <linux/irqchip/bcm2835.h>
 #include <linux/of_platform.h>
 #include <linux/bcm2835_timer.h>
+#include <linux/clk/bcm2835.h>
 
 #include <asm/mach/arch.h>
 #include <asm/mach/map.h>
@@ -38,6 +39,8 @@ void __init bcm2835_init(void)
 {
 	int ret;
 
+	bcm2835_init_clocks();
+
 	ret = of_platform_populate(NULL, of_default_bus_match_table, NULL,
 				   NULL);
 	if (ret) {
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index 5869ea3..d5c19d1 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -3,6 +3,7 @@ obj-$(CONFIG_CLKDEV_LOOKUP)	+= clkdev.o
 obj-$(CONFIG_COMMON_CLK)	+= clk.o clk-fixed-rate.o clk-gate.o \
 				   clk-mux.o clk-divider.o clk-fixed-factor.o
 # SoCs specific
+obj-$(CONFIG_ARCH_BCM2835)	+= clk-bcm2835.o
 obj-$(CONFIG_ARCH_NOMADIK)	+= clk-nomadik.o
 obj-$(CONFIG_ARCH_HIGHBANK)	+= clk-highbank.o
 obj-$(CONFIG_ARCH_MXS)		+= mxs/
diff --git a/drivers/clk/clk-bcm2835.c b/drivers/clk/clk-bcm2835.c
new file mode 100644
index 0000000..ad65f0e
--- /dev/null
+++ b/drivers/clk/clk-bcm2835.c
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2010 Broadcom
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/clkdev.h>
+#include <linux/clk/bcm2835.h>
+
+/*
+ * These are fixed clocks. They're probably not all root clocks and it may
+ * be possible to turn them on and off but until this is mapped out better
+ * it's the only way they can be used.
+ */
+void __init bcm2835_init_clocks(void)
+{
+	struct clk *clk;
+	int ret;
+
+	clk = clk_register_fixed_rate(NULL, "sys_pclk", NULL, CLK_IS_ROOT,
+					250000000);
+	if (!clk)
+		pr_err("sys_pclk not registered\n");
+
+	clk = clk_register_fixed_rate(NULL, "apb_pclk", NULL, CLK_IS_ROOT,
+					126000000);
+	if (!clk)
+		pr_err("apb_pclk not registered\n");
+
+	clk = clk_register_fixed_rate(NULL, "uart0_pclk", NULL, CLK_IS_ROOT,
+					3000000);
+	if (!clk)
+		pr_err("uart0_pclk not registered\n");
+	ret = clk_register_clkdev(clk, NULL, "20201000.uart");
+	if (ret)
+		pr_err("uart0_pclk alias not registered\n");
+
+	clk = clk_register_fixed_rate(NULL, "uart1_pclk", NULL, CLK_IS_ROOT,
+					125000000);
+	if (!clk)
+		pr_err("uart1_pclk not registered\n");
+	ret = clk_register_clkdev(clk, NULL, "20215000.uart");
+	if (ret)
+		pr_err("uart0_pclk alias not registered\n");
+}
diff --git a/include/linux/clk/bcm2835.h b/include/linux/clk/bcm2835.h
new file mode 100644
index 0000000..aa937f6
--- /dev/null
+++ b/include/linux/clk/bcm2835.h
@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) 2010 Broadcom
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef __LINUX_CLK_BCM2835_H_
+#define __LINUX_CLK_BCM2835_H_
+
+void __init bcm2835_init_clocks(void);
+
+#endif
-- 
1.7.9.5

[PATCH V6] ARM: bcm2835: add stub clock driver

[Domenico Andreoli]

Hi Stephen,

On Sep 19, 2012 5:57 AM, "Stephen Warren" <swarren@wwwdotorg.org> wrote:
> diff --git a/drivers/clk/clk-bcm2835.c b/drivers/clk/clk-bcm2835.c
> new file mode 100644
> index 0000000..ad65f0e
> --- /dev/null
> +++ b/drivers/clk/clk-bcm2835.c
> @@ -0,0 +1,58 @@
> +/*
> + * Copyright (C) 2010 Broadcom
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
 USA
> + */

why the copyright is of Broadcom? these files are written from scratch or
anyway being reworked quite a bit, right?

cheers,
Domenico
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[PATCH V6] ARM: bcm2835: add stub clock driver

[Mike Turquette]

Quoting Stephen Warren (2012-09-18 20:56:13)
> From: Simon Arlott <simon@fire.lp0.eu>
> 
> This patch adds a minimal stub clock driver for the BCM2835. Its sole
> purpose is to allow the PL011 AMBA clk_get() API calls to provide
> something that looks enough like a clock that the driver probes and
> operates correctly.
> 
> This patch was extracted from git://github.com/lp0/linux.git branch
> rpi-split as of 2012/09/08, and modified as follows:
> 
> * Reworked to call clk_register_fixed_rate(), and clk_register_clkdev()
>   rather than using static data to represent the clocks.
> * Moved implementation to drivers/clk/.
> * Modified .dev_id for UART clocks to match UART DT node names.
> * s/bcm2708/bcm2835/.
> * Modified device tree vendor prefix.
> 
> Signed-off-by: Chris Boot <bootc@bootc.net>
> Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
> Signed-off-by: Dom Cobley <popcornmix@gmail.com>
> Signed-off-by: Dom Cobley <dc4@broadcom.com>
> Cc: Mike Turquette <mturquette@linaro.org>
> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>

Acked-by: Mike Turquette <mturquette@linaro.org>

Regards,
Mike

> --
> v6:
> * Reworked to call clk_register_fixed_rate(), and clk_register_clkdev()
>   rather than using static data to represent the clocks.
> v5:
> * No change.
> v4:
> * Moved implementation to drivers/clk/.
> * s/bcm2708/bcm2835/.
> * Updated for new device tree vendor prefix.
> v3:
> * New patch.
> 
> clk fixup
> ---
>  arch/arm/mach-bcm2835/bcm2835.c |    3 ++
>  drivers/clk/Makefile            |    1 +
>  drivers/clk/clk-bcm2835.c       |   58 +++++++++++++++++++++++++++++++++++++++
>  include/linux/clk/bcm2835.h     |   24 ++++++++++++++++
>  4 files changed, 86 insertions(+)
>  create mode 100644 drivers/clk/clk-bcm2835.c
>  create mode 100644 include/linux/clk/bcm2835.h
> 
> diff --git a/arch/arm/mach-bcm2835/bcm2835.c b/arch/arm/mach-bcm2835/bcm2835.c
> index e3f2968..f6fea49 100644
> --- a/arch/arm/mach-bcm2835/bcm2835.c
> +++ b/arch/arm/mach-bcm2835/bcm2835.c
> @@ -16,6 +16,7 @@
>  #include <linux/irqchip/bcm2835.h>
>  #include <linux/of_platform.h>
>  #include <linux/bcm2835_timer.h>
> +#include <linux/clk/bcm2835.h>
>  
>  #include <asm/mach/arch.h>
>  #include <asm/mach/map.h>
> @@ -38,6 +39,8 @@ void __init bcm2835_init(void)
>  {
>         int ret;
>  
> +       bcm2835_init_clocks();
> +
>         ret = of_platform_populate(NULL, of_default_bus_match_table, NULL,
>                                    NULL);
>         if (ret) {
> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
> index 5869ea3..d5c19d1 100644
> --- a/drivers/clk/Makefile
> +++ b/drivers/clk/Makefile
> @@ -3,6 +3,7 @@ obj-$(CONFIG_CLKDEV_LOOKUP)     += clkdev.o
>  obj-$(CONFIG_COMMON_CLK)       += clk.o clk-fixed-rate.o clk-gate.o \
>                                    clk-mux.o clk-divider.o clk-fixed-factor.o
>  # SoCs specific
> +obj-$(CONFIG_ARCH_BCM2835)     += clk-bcm2835.o
>  obj-$(CONFIG_ARCH_NOMADIK)     += clk-nomadik.o
>  obj-$(CONFIG_ARCH_HIGHBANK)    += clk-highbank.o
>  obj-$(CONFIG_ARCH_MXS)         += mxs/
> diff --git a/drivers/clk/clk-bcm2835.c b/drivers/clk/clk-bcm2835.c
> new file mode 100644
> index 0000000..ad65f0e
> --- /dev/null
> +++ b/drivers/clk/clk-bcm2835.c
> @@ -0,0 +1,58 @@
> +/*
> + * Copyright (C) 2010 Broadcom
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
> + */
> +
> +#include <linux/clk-provider.h>
> +#include <linux/clkdev.h>
> +#include <linux/clk/bcm2835.h>
> +
> +/*
> + * These are fixed clocks. They're probably not all root clocks and it may
> + * be possible to turn them on and off but until this is mapped out better
> + * it's the only way they can be used.
> + */
> +void __init bcm2835_init_clocks(void)
> +{
> +       struct clk *clk;
> +       int ret;
> +
> +       clk = clk_register_fixed_rate(NULL, "sys_pclk", NULL, CLK_IS_ROOT,
> +                                       250000000);
> +       if (!clk)
> +               pr_err("sys_pclk not registered\n");
> +
> +       clk = clk_register_fixed_rate(NULL, "apb_pclk", NULL, CLK_IS_ROOT,
> +                                       126000000);
> +       if (!clk)
> +               pr_err("apb_pclk not registered\n");
> +
> +       clk = clk_register_fixed_rate(NULL, "uart0_pclk", NULL, CLK_IS_ROOT,
> +                                       3000000);
> +       if (!clk)
> +               pr_err("uart0_pclk not registered\n");
> +       ret = clk_register_clkdev(clk, NULL, "20201000.uart");
> +       if (ret)
> +               pr_err("uart0_pclk alias not registered\n");
> +
> +       clk = clk_register_fixed_rate(NULL, "uart1_pclk", NULL, CLK_IS_ROOT,
> +                                       125000000);
> +       if (!clk)
> +               pr_err("uart1_pclk not registered\n");
> +       ret = clk_register_clkdev(clk, NULL, "20215000.uart");
> +       if (ret)
> +               pr_err("uart0_pclk alias not registered\n");
> +}
> diff --git a/include/linux/clk/bcm2835.h b/include/linux/clk/bcm2835.h
> new file mode 100644
> index 0000000..aa937f6
> --- /dev/null
> +++ b/include/linux/clk/bcm2835.h
> @@ -0,0 +1,24 @@
> +/*
> + * Copyright (C) 2010 Broadcom
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
> + */
> +
> +#ifndef __LINUX_CLK_BCM2835_H_
> +#define __LINUX_CLK_BCM2835_H_
> +
> +void __init bcm2835_init_clocks(void);
> +
> +#endif
> -- 
> 1.7.9.5
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH V6] ARM: bcm2835: add stub clock driver

[Stephen Warren]

On 09/19/2012 02:54 AM, Domenico Andreoli wrote:
> Hi Stephen,
> 
> On Sep 19, 2012 5:57 AM, "Stephen Warren" <swarren@wwwdotorg.org
> <mailto:swarren@wwwdotorg.org>> wrote:
>> diff --git a/drivers/clk/clk-bcm2835.c b/drivers/clk/clk-bcm2835.c
>> new file mode 100644
>> index 0000000..ad65f0e
>> --- /dev/null
>> +++ b/drivers/clk/clk-bcm2835.c
>> @@ -0,0 +1,58 @@
>> +/*
>> + * Copyright (C) 2010 Broadcom
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License as published by
>> + * the Free Software Foundation; either version 2 of the License, or
>> + * (at your option) any later version.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License
>> + * along with this program; if not, write to the Free Software
>> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
>  02111-1307  USA
>> + */
> 
> why the copyright is of Broadcom? these files are written from scratch
> or anyway being reworked quite a bit, right?

The original code in Simon's branch has this (c) message so I maintained
it. I honestly don't know whether Simon wrote this patch from scratch or
derived it from Broadcom code.

Given the rework I did, I suppose I should have added my (c) on this
patchset too though; I can fix that up locally before sending the pull
request unless you have objections.

[PATCH V6] ARM: bcm2835: add stub clock driver

[Domenico Andreoli]

On Wed, Sep 19, 2012 at 10:15:02AM -0600, Stephen Warren wrote:
> On 09/19/2012 02:54 AM, Domenico Andreoli wrote:
> > Hi Stephen,
> > 
> > On Sep 19, 2012 5:57 AM, "Stephen Warren" <swarren@wwwdotorg.org
> > <mailto:swarren@wwwdotorg.org>> wrote:
> >> diff --git a/drivers/clk/clk-bcm2835.c b/drivers/clk/clk-bcm2835.c
> >> new file mode 100644
> >> index 0000000..ad65f0e
> >> --- /dev/null
> >> +++ b/drivers/clk/clk-bcm2835.c
> >> @@ -0,0 +1,58 @@
> >> +/*
> >> + * Copyright (C) 2010 Broadcom
> >> + *
> >> + * This program is free software; you can redistribute it and/or modify
> >> + * it under the terms of the GNU General Public License as published by
> >> + * the Free Software Foundation; either version 2 of the License, or
> >> + * (at your option) any later version.
> >> + *
> >> + * This program is distributed in the hope that it will be useful,
> >> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> >> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> >> + * GNU General Public License for more details.
> >> + *
> >> + * You should have received a copy of the GNU General Public License
> >> + * along with this program; if not, write to the Free Software
> >> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
> >  02111-1307  USA
> >> + */
> > 
> > why the copyright is of Broadcom? these files are written from scratch
> > or anyway being reworked quite a bit, right?
> 
> The original code in Simon's branch has this (c) message so I maintained
> it. I honestly don't know whether Simon wrote this patch from scratch or
> derived it from Broadcom code.
> 
> Given the rework I did, I suppose I should have added my (c) on this
> patchset too though; I can fix that up locally before sending the pull
> request unless you have objections.

No objections for sure. Thanks.

Domenico