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/*
* 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;
}
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