[PATCH V6] ARM: bcm2835: add stub clock driver
Mike Turquette
mturquette at linaro.org
Wed Sep 19 11:38:12 EDT 2012
Quoting Stephen Warren (2012-09-18 20:56:13)
> From: Simon Arlott <simon at 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 at bootc.net>
> Signed-off-by: Simon Arlott <simon at fire.lp0.eu>
> Signed-off-by: Dom Cobley <popcornmix at gmail.com>
> Signed-off-by: Dom Cobley <dc4 at broadcom.com>
> Cc: Mike Turquette <mturquette at linaro.org>
> Signed-off-by: Stephen Warren <swarren at wwwdotorg.org>
Acked-by: Mike Turquette <mturquette at 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
>
>
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