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![Boris Brezillon](/assets/img/avatar_default.png)
Some PWM drivers are testing the PWMF_ENABLED flag. Create a helper function to hide the logic behind enabled test. This will allow us to smoothly move from the current approach to an atomic PWM update approach. Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
480 lines
12 KiB
C
480 lines
12 KiB
C
/*
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* R-Mobile TPU PWM driver
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*
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* Copyright (C) 2012 Renesas Solutions Corp.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/clk.h>
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#include <linux/err.h>
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#include <linux/io.h>
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#include <linux/init.h>
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#include <linux/ioport.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/pm_runtime.h>
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#include <linux/pwm.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#define TPU_CHANNEL_MAX 4
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#define TPU_TSTR 0x00 /* Timer start register (shared) */
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#define TPU_TCRn 0x00 /* Timer control register */
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#define TPU_TCR_CCLR_NONE (0 << 5)
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#define TPU_TCR_CCLR_TGRA (1 << 5)
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#define TPU_TCR_CCLR_TGRB (2 << 5)
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#define TPU_TCR_CCLR_TGRC (5 << 5)
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#define TPU_TCR_CCLR_TGRD (6 << 5)
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#define TPU_TCR_CKEG_RISING (0 << 3)
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#define TPU_TCR_CKEG_FALLING (1 << 3)
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#define TPU_TCR_CKEG_BOTH (2 << 3)
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#define TPU_TMDRn 0x04 /* Timer mode register */
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#define TPU_TMDR_BFWT (1 << 6)
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#define TPU_TMDR_BFB (1 << 5)
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#define TPU_TMDR_BFA (1 << 4)
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#define TPU_TMDR_MD_NORMAL (0 << 0)
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#define TPU_TMDR_MD_PWM (2 << 0)
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#define TPU_TIORn 0x08 /* Timer I/O control register */
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#define TPU_TIOR_IOA_0 (0 << 0)
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#define TPU_TIOR_IOA_0_CLR (1 << 0)
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#define TPU_TIOR_IOA_0_SET (2 << 0)
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#define TPU_TIOR_IOA_0_TOGGLE (3 << 0)
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#define TPU_TIOR_IOA_1 (4 << 0)
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#define TPU_TIOR_IOA_1_CLR (5 << 0)
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#define TPU_TIOR_IOA_1_SET (6 << 0)
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#define TPU_TIOR_IOA_1_TOGGLE (7 << 0)
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#define TPU_TIERn 0x0c /* Timer interrupt enable register */
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#define TPU_TSRn 0x10 /* Timer status register */
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#define TPU_TCNTn 0x14 /* Timer counter */
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#define TPU_TGRAn 0x18 /* Timer general register A */
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#define TPU_TGRBn 0x1c /* Timer general register B */
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#define TPU_TGRCn 0x20 /* Timer general register C */
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#define TPU_TGRDn 0x24 /* Timer general register D */
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#define TPU_CHANNEL_OFFSET 0x10
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#define TPU_CHANNEL_SIZE 0x40
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enum tpu_pin_state {
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TPU_PIN_INACTIVE, /* Pin is driven inactive */
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TPU_PIN_PWM, /* Pin is driven by PWM */
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TPU_PIN_ACTIVE, /* Pin is driven active */
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};
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struct tpu_device;
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struct tpu_pwm_device {
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bool timer_on; /* Whether the timer is running */
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struct tpu_device *tpu;
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unsigned int channel; /* Channel number in the TPU */
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enum pwm_polarity polarity;
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unsigned int prescaler;
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u16 period;
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u16 duty;
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};
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struct tpu_device {
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struct platform_device *pdev;
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struct pwm_chip chip;
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spinlock_t lock;
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void __iomem *base;
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struct clk *clk;
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};
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#define to_tpu_device(c) container_of(c, struct tpu_device, chip)
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static void tpu_pwm_write(struct tpu_pwm_device *pwm, int reg_nr, u16 value)
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{
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void __iomem *base = pwm->tpu->base + TPU_CHANNEL_OFFSET
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+ pwm->channel * TPU_CHANNEL_SIZE;
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iowrite16(value, base + reg_nr);
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}
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static void tpu_pwm_set_pin(struct tpu_pwm_device *pwm,
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enum tpu_pin_state state)
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{
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static const char * const states[] = { "inactive", "PWM", "active" };
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dev_dbg(&pwm->tpu->pdev->dev, "%u: configuring pin as %s\n",
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pwm->channel, states[state]);
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switch (state) {
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case TPU_PIN_INACTIVE:
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tpu_pwm_write(pwm, TPU_TIORn,
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pwm->polarity == PWM_POLARITY_INVERSED ?
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TPU_TIOR_IOA_1 : TPU_TIOR_IOA_0);
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break;
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case TPU_PIN_PWM:
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tpu_pwm_write(pwm, TPU_TIORn,
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pwm->polarity == PWM_POLARITY_INVERSED ?
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TPU_TIOR_IOA_0_SET : TPU_TIOR_IOA_1_CLR);
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break;
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case TPU_PIN_ACTIVE:
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tpu_pwm_write(pwm, TPU_TIORn,
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pwm->polarity == PWM_POLARITY_INVERSED ?
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TPU_TIOR_IOA_0 : TPU_TIOR_IOA_1);
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break;
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}
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}
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static void tpu_pwm_start_stop(struct tpu_pwm_device *pwm, int start)
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{
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unsigned long flags;
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u16 value;
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spin_lock_irqsave(&pwm->tpu->lock, flags);
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value = ioread16(pwm->tpu->base + TPU_TSTR);
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if (start)
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value |= 1 << pwm->channel;
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else
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value &= ~(1 << pwm->channel);
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iowrite16(value, pwm->tpu->base + TPU_TSTR);
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spin_unlock_irqrestore(&pwm->tpu->lock, flags);
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}
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static int tpu_pwm_timer_start(struct tpu_pwm_device *pwm)
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{
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int ret;
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if (!pwm->timer_on) {
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/* Wake up device and enable clock. */
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pm_runtime_get_sync(&pwm->tpu->pdev->dev);
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ret = clk_prepare_enable(pwm->tpu->clk);
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if (ret) {
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dev_err(&pwm->tpu->pdev->dev, "cannot enable clock\n");
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return ret;
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}
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pwm->timer_on = true;
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}
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/*
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* Make sure the channel is stopped, as we need to reconfigure it
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* completely. First drive the pin to the inactive state to avoid
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* glitches.
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*/
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tpu_pwm_set_pin(pwm, TPU_PIN_INACTIVE);
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tpu_pwm_start_stop(pwm, false);
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/*
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* - Clear TCNT on TGRB match
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* - Count on rising edge
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* - Set prescaler
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* - Output 0 until TGRA, output 1 until TGRB (active low polarity)
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* - Output 1 until TGRA, output 0 until TGRB (active high polarity
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* - PWM mode
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*/
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tpu_pwm_write(pwm, TPU_TCRn, TPU_TCR_CCLR_TGRB | TPU_TCR_CKEG_RISING |
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pwm->prescaler);
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tpu_pwm_write(pwm, TPU_TMDRn, TPU_TMDR_MD_PWM);
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tpu_pwm_set_pin(pwm, TPU_PIN_PWM);
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tpu_pwm_write(pwm, TPU_TGRAn, pwm->duty);
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tpu_pwm_write(pwm, TPU_TGRBn, pwm->period);
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dev_dbg(&pwm->tpu->pdev->dev, "%u: TGRA 0x%04x TGRB 0x%04x\n",
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pwm->channel, pwm->duty, pwm->period);
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/* Start the channel. */
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tpu_pwm_start_stop(pwm, true);
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return 0;
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}
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static void tpu_pwm_timer_stop(struct tpu_pwm_device *pwm)
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{
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if (!pwm->timer_on)
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return;
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/* Disable channel. */
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tpu_pwm_start_stop(pwm, false);
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/* Stop clock and mark device as idle. */
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clk_disable_unprepare(pwm->tpu->clk);
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pm_runtime_put(&pwm->tpu->pdev->dev);
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pwm->timer_on = false;
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}
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/* -----------------------------------------------------------------------------
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* PWM API
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*/
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static int tpu_pwm_request(struct pwm_chip *chip, struct pwm_device *_pwm)
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{
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struct tpu_device *tpu = to_tpu_device(chip);
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struct tpu_pwm_device *pwm;
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if (_pwm->hwpwm >= TPU_CHANNEL_MAX)
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return -EINVAL;
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pwm = kzalloc(sizeof(*pwm), GFP_KERNEL);
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if (pwm == NULL)
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return -ENOMEM;
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pwm->tpu = tpu;
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pwm->channel = _pwm->hwpwm;
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pwm->polarity = PWM_POLARITY_NORMAL;
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pwm->prescaler = 0;
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pwm->period = 0;
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pwm->duty = 0;
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pwm->timer_on = false;
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pwm_set_chip_data(_pwm, pwm);
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return 0;
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}
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static void tpu_pwm_free(struct pwm_chip *chip, struct pwm_device *_pwm)
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{
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struct tpu_pwm_device *pwm = pwm_get_chip_data(_pwm);
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tpu_pwm_timer_stop(pwm);
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kfree(pwm);
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}
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static int tpu_pwm_config(struct pwm_chip *chip, struct pwm_device *_pwm,
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int duty_ns, int period_ns)
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{
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static const unsigned int prescalers[] = { 1, 4, 16, 64 };
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struct tpu_pwm_device *pwm = pwm_get_chip_data(_pwm);
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struct tpu_device *tpu = to_tpu_device(chip);
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unsigned int prescaler;
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bool duty_only = false;
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u32 clk_rate;
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u32 period;
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u32 duty;
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int ret;
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/*
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* Pick a prescaler to avoid overflowing the counter.
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* TODO: Pick the highest acceptable prescaler.
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*/
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clk_rate = clk_get_rate(tpu->clk);
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for (prescaler = 0; prescaler < ARRAY_SIZE(prescalers); ++prescaler) {
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period = clk_rate / prescalers[prescaler]
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/ (NSEC_PER_SEC / period_ns);
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if (period <= 0xffff)
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break;
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}
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if (prescaler == ARRAY_SIZE(prescalers) || period == 0) {
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dev_err(&tpu->pdev->dev, "clock rate mismatch\n");
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return -ENOTSUPP;
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}
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if (duty_ns) {
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duty = clk_rate / prescalers[prescaler]
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/ (NSEC_PER_SEC / duty_ns);
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if (duty > period)
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return -EINVAL;
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} else {
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duty = 0;
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}
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dev_dbg(&tpu->pdev->dev,
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"rate %u, prescaler %u, period %u, duty %u\n",
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clk_rate, prescalers[prescaler], period, duty);
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if (pwm->prescaler == prescaler && pwm->period == period)
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duty_only = true;
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pwm->prescaler = prescaler;
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pwm->period = period;
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pwm->duty = duty;
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/* If the channel is disabled we're done. */
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if (!pwm_is_enabled(_pwm))
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return 0;
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if (duty_only && pwm->timer_on) {
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/*
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* If only the duty cycle changed and the timer is already
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* running, there's no need to reconfigure it completely, Just
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* modify the duty cycle.
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*/
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tpu_pwm_write(pwm, TPU_TGRAn, pwm->duty);
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dev_dbg(&tpu->pdev->dev, "%u: TGRA 0x%04x\n", pwm->channel,
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pwm->duty);
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} else {
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/* Otherwise perform a full reconfiguration. */
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ret = tpu_pwm_timer_start(pwm);
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if (ret < 0)
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return ret;
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}
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if (duty == 0 || duty == period) {
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/*
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* To avoid running the timer when not strictly required, handle
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* 0% and 100% duty cycles as fixed levels and stop the timer.
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*/
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tpu_pwm_set_pin(pwm, duty ? TPU_PIN_ACTIVE : TPU_PIN_INACTIVE);
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tpu_pwm_timer_stop(pwm);
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}
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return 0;
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}
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static int tpu_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *_pwm,
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enum pwm_polarity polarity)
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{
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struct tpu_pwm_device *pwm = pwm_get_chip_data(_pwm);
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pwm->polarity = polarity;
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return 0;
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}
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static int tpu_pwm_enable(struct pwm_chip *chip, struct pwm_device *_pwm)
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{
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struct tpu_pwm_device *pwm = pwm_get_chip_data(_pwm);
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int ret;
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ret = tpu_pwm_timer_start(pwm);
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if (ret < 0)
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return ret;
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/*
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* To avoid running the timer when not strictly required, handle 0% and
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* 100% duty cycles as fixed levels and stop the timer.
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*/
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if (pwm->duty == 0 || pwm->duty == pwm->period) {
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tpu_pwm_set_pin(pwm, pwm->duty ?
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TPU_PIN_ACTIVE : TPU_PIN_INACTIVE);
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tpu_pwm_timer_stop(pwm);
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}
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return 0;
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}
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static void tpu_pwm_disable(struct pwm_chip *chip, struct pwm_device *_pwm)
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{
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struct tpu_pwm_device *pwm = pwm_get_chip_data(_pwm);
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/* The timer must be running to modify the pin output configuration. */
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tpu_pwm_timer_start(pwm);
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tpu_pwm_set_pin(pwm, TPU_PIN_INACTIVE);
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tpu_pwm_timer_stop(pwm);
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}
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static const struct pwm_ops tpu_pwm_ops = {
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.request = tpu_pwm_request,
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.free = tpu_pwm_free,
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.config = tpu_pwm_config,
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.set_polarity = tpu_pwm_set_polarity,
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.enable = tpu_pwm_enable,
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.disable = tpu_pwm_disable,
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.owner = THIS_MODULE,
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};
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/* -----------------------------------------------------------------------------
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* Probe and remove
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*/
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static int tpu_probe(struct platform_device *pdev)
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{
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struct tpu_device *tpu;
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struct resource *res;
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int ret;
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tpu = devm_kzalloc(&pdev->dev, sizeof(*tpu), GFP_KERNEL);
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if (tpu == NULL)
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return -ENOMEM;
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spin_lock_init(&tpu->lock);
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tpu->pdev = pdev;
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/* Map memory, get clock and pin control. */
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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tpu->base = devm_ioremap_resource(&pdev->dev, res);
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if (IS_ERR(tpu->base))
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return PTR_ERR(tpu->base);
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tpu->clk = devm_clk_get(&pdev->dev, NULL);
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if (IS_ERR(tpu->clk)) {
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dev_err(&pdev->dev, "cannot get clock\n");
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return PTR_ERR(tpu->clk);
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}
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/* Initialize and register the device. */
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platform_set_drvdata(pdev, tpu);
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tpu->chip.dev = &pdev->dev;
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tpu->chip.ops = &tpu_pwm_ops;
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tpu->chip.of_xlate = of_pwm_xlate_with_flags;
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tpu->chip.of_pwm_n_cells = 3;
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tpu->chip.base = -1;
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tpu->chip.npwm = TPU_CHANNEL_MAX;
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ret = pwmchip_add(&tpu->chip);
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if (ret < 0) {
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dev_err(&pdev->dev, "failed to register PWM chip\n");
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return ret;
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}
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dev_info(&pdev->dev, "TPU PWM %d registered\n", tpu->pdev->id);
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pm_runtime_enable(&pdev->dev);
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return 0;
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}
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static int tpu_remove(struct platform_device *pdev)
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{
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struct tpu_device *tpu = platform_get_drvdata(pdev);
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int ret;
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ret = pwmchip_remove(&tpu->chip);
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if (ret)
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return ret;
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pm_runtime_disable(&pdev->dev);
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return 0;
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}
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#ifdef CONFIG_OF
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static const struct of_device_id tpu_of_table[] = {
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{ .compatible = "renesas,tpu-r8a73a4", },
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{ .compatible = "renesas,tpu-r8a7740", },
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{ .compatible = "renesas,tpu-r8a7790", },
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{ .compatible = "renesas,tpu-sh7372", },
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{ .compatible = "renesas,tpu", },
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{ },
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};
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MODULE_DEVICE_TABLE(of, tpu_of_table);
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#endif
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static struct platform_driver tpu_driver = {
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.probe = tpu_probe,
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.remove = tpu_remove,
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.driver = {
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.name = "renesas-tpu-pwm",
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.of_match_table = of_match_ptr(tpu_of_table),
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}
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};
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module_platform_driver(tpu_driver);
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MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
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MODULE_DESCRIPTION("Renesas TPU PWM Driver");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS("platform:renesas-tpu-pwm");
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