diff options
Diffstat (limited to 'arch/arm/cpu')
| -rw-r--r-- | arch/arm/cpu/armv7/tegra20/Makefile | 1 | ||||
| -rw-r--r-- | arch/arm/cpu/armv7/tegra20/pwm.c | 101 |
2 files changed, 102 insertions, 0 deletions
diff --git a/arch/arm/cpu/armv7/tegra20/Makefile b/arch/arm/cpu/armv7/tegra20/Makefile index 09a0314..77cb4d1 100644 --- a/arch/arm/cpu/armv7/tegra20/Makefile +++ b/arch/arm/cpu/armv7/tegra20/Makefile @@ -28,6 +28,7 @@ include $(TOPDIR)/config.mk LIB = $(obj)lib$(SOC).o COBJS-$(CONFIG_USB_EHCI_TEGRA) += usb.o +COBJS-$(CONFIG_PWM_TEGRA) += pwm.o COBJS := $(COBJS-y) SRCS := $(COBJS:.o=.c) diff --git a/arch/arm/cpu/armv7/tegra20/pwm.c b/arch/arm/cpu/armv7/tegra20/pwm.c new file mode 100644 index 0000000..b655c5c --- /dev/null +++ b/arch/arm/cpu/armv7/tegra20/pwm.c @@ -0,0 +1,101 @@ +/* + * Tegra2 pulse width frequency modulator definitions + * + * Copyright (c) 2011 The Chromium OS Authors. + * See file CREDITS for list of people who contributed to this + * project. + * + * 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 <common.h> +#include <fdtdec.h> +#include <asm/io.h> +#include <asm/arch/clock.h> +#include <asm/arch/pwm.h> + +struct pwm_info { + struct pwm_ctlr *pwm; /* Registers for our pwm controller */ + int pwm_node; /* PWM device tree node */ +} local; + +void pwm_enable(unsigned channel, int rate, int pulse_width, int freq_divider) +{ + u32 reg; + + assert(channel < PWM_NUM_CHANNELS); + + /* TODO: Can we use clock_adjust_periph_pll_div() here? */ + clock_start_periph_pll(PERIPH_ID_PWM, CLOCK_ID_SFROM32KHZ, rate); + + reg = PWM_ENABLE_MASK; + reg |= pulse_width << PWM_WIDTH_SHIFT; + reg |= freq_divider << PWM_DIVIDER_SHIFT; + writel(reg, &local.pwm[channel].control); + debug("%s: channel=%d, rate=%d\n", __func__, channel, rate); +} + +int pwm_request(const void *blob, int node, const char *prop_name) +{ + int pwm_node; + u32 data[3]; + + if (fdtdec_get_int_array(blob, node, prop_name, data, + ARRAY_SIZE(data))) { + debug("%s: Cannot decode PWM property '%s'\n", __func__, + prop_name); + return -1; + } + + pwm_node = fdt_node_offset_by_phandle(blob, data[0]); + if (pwm_node != local.pwm_node) { + debug("%s: PWM property '%s' phandle %d not recognised" + "- expecting %d\n", __func__, prop_name, data[0], + local.pwm_node); + return -1; + } + if (data[1] >= PWM_NUM_CHANNELS) { + debug("%s: PWM property '%s': invalid channel %u\n", __func__, + prop_name, data[1]); + return -1; + } + + /* + * TODO: We could maintain a list of requests, but it might not be + * worth it for U-Boot. + */ + return data[1]; +} + +int pwm_init(const void *blob) +{ + local.pwm_node = fdtdec_next_compatible(blob, 0, + COMPAT_NVIDIA_TEGRA20_PWM); + if (local.pwm_node < 0) { + debug("%s: Cannot find device tree node\n", __func__); + return -1; + } + + local.pwm = (struct pwm_ctlr *)fdtdec_get_addr(blob, local.pwm_node, + "reg"); + if (local.pwm == (struct pwm_ctlr *)FDT_ADDR_T_NONE) { + debug("%s: Cannot find pwm reg address\n", __func__); + return -1; + } + debug("Tegra PWM at %p, node %d\n", local.pwm, local.pwm_node); + + return 0; +} |