From 75fabc3f64489aa2c52eec54cd433ea269a25e05 Mon Sep 17 00:00:00 2001 From: Simon Arlott Date: Mon, 10 Sep 2012 23:26:15 -0600 Subject: [PATCH] ARM: bcm2835: add stub clock driver 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 Signed-off-by: Simon Arlott Signed-off-by: Dom Cobley Signed-off-by: Dom Cobley Signed-off-by: Stephen Warren Acked-by: Mike Turquette --- arch/arm/mach-bcm2835/bcm2835.c | 3 ++ drivers/clk/Makefile | 1 + drivers/clk/clk-bcm2835.c | 59 +++++++++++++++++++++++++++++++++ include/linux/clk/bcm2835.h | 24 ++++++++++++++ 4 files changed, 87 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 e3f296860dd0..f6fea4933571 100644 --- a/arch/arm/mach-bcm2835/bcm2835.c +++ b/arch/arm/mach-bcm2835/bcm2835.c @@ -16,6 +16,7 @@ #include #include #include +#include #include #include @@ -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 5869ea387054..d5c19d1e0cf8 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 000000000000..67ad16b20b81 --- /dev/null +++ b/drivers/clk/clk-bcm2835.c @@ -0,0 +1,59 @@ +/* + * Copyright (C) 2010 Broadcom + * Copyright (C) 2012 Stephen Warren + * + * 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 +#include +#include + +/* + * 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 000000000000..aa937f6c17da --- /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