forked from rrcarlosr/Jetpack
70 lines
1.4 KiB
C
70 lines
1.4 KiB
C
/*
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* (C) Copyright 2014
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* Heiko Schocher, DENX Software Engineering, hs@denx.de.
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*
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* Basic support for the pwm modul on imx6.
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*
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* Based on linux:drivers/pwm/pwm-imx.c
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* from
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* Sascha Hauer <s.hauer@pengutronix.de>
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*
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* SPDX-License-Identifier: GPL-2.0
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*/
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#include <common.h>
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#include <div64.h>
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#include <asm/arch/imx-regs.h>
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/* pwm_id from 0..3 */
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struct pwm_regs *pwm_id_to_reg(int pwm_id)
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{
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switch (pwm_id) {
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case 0:
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return (struct pwm_regs *)PWM1_BASE_ADDR;
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case 1:
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return (struct pwm_regs *)PWM2_BASE_ADDR;
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case 2:
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return (struct pwm_regs *)PWM3_BASE_ADDR;
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case 3:
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return (struct pwm_regs *)PWM4_BASE_ADDR;
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default:
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printf("unknown pwm_id: %d\n", pwm_id);
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break;
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}
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return NULL;
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}
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int pwm_imx_get_parms(int period_ns, int duty_ns, unsigned long *period_c,
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unsigned long *duty_c, unsigned long *prescale)
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{
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unsigned long long c;
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/*
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* we have not yet a clock framework for imx6, so add the clock
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* value here as a define. Replace it when we have the clock
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* framework.
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*/
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c = CONFIG_IMX6_PWM_PER_CLK;
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c = c * period_ns;
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do_div(c, 1000000000);
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*period_c = c;
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*prescale = *period_c / 0x10000 + 1;
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*period_c /= *prescale;
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c = *period_c * (unsigned long long)duty_ns;
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do_div(c, period_ns);
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*duty_c = c;
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/*
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* according to imx pwm RM, the real period value should be
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* PERIOD value in PWMPR plus 2.
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*/
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if (*period_c > 2)
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*period_c -= 2;
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else
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*period_c = 0;
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return 0;
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}
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