274 lines
6.2 KiB
C
274 lines
6.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* R-Car PWM Timer driver
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*
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* Copyright (C) 2015 Renesas Electronics Corporation
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*
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* Limitations:
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* - The hardware cannot generate a 0% duty cycle.
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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/log2.h>
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#include <linux/math64.h>
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#include <linux/module.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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#define RCAR_PWM_MAX_DIVISION 24
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#define RCAR_PWM_MAX_CYCLE 1023
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#define RCAR_PWMCR 0x00
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#define RCAR_PWMCR_CC0_MASK 0x000f0000
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#define RCAR_PWMCR_CC0_SHIFT 16
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#define RCAR_PWMCR_CCMD BIT(15)
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#define RCAR_PWMCR_SYNC BIT(11)
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#define RCAR_PWMCR_SS0 BIT(4)
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#define RCAR_PWMCR_EN0 BIT(0)
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#define RCAR_PWMCNT 0x04
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#define RCAR_PWMCNT_CYC0_MASK 0x03ff0000
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#define RCAR_PWMCNT_CYC0_SHIFT 16
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#define RCAR_PWMCNT_PH0_MASK 0x000003ff
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#define RCAR_PWMCNT_PH0_SHIFT 0
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struct rcar_pwm_chip {
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struct pwm_chip chip;
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void __iomem *base;
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struct clk *clk;
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};
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static inline struct rcar_pwm_chip *to_rcar_pwm_chip(struct pwm_chip *chip)
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{
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return container_of(chip, struct rcar_pwm_chip, chip);
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}
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static void rcar_pwm_write(struct rcar_pwm_chip *rp, u32 data,
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unsigned int offset)
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{
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writel(data, rp->base + offset);
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}
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static u32 rcar_pwm_read(struct rcar_pwm_chip *rp, unsigned int offset)
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{
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return readl(rp->base + offset);
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}
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static void rcar_pwm_update(struct rcar_pwm_chip *rp, u32 mask, u32 data,
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unsigned int offset)
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{
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u32 value;
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value = rcar_pwm_read(rp, offset);
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value &= ~mask;
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value |= data & mask;
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rcar_pwm_write(rp, value, offset);
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}
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static int rcar_pwm_get_clock_division(struct rcar_pwm_chip *rp, int period_ns)
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{
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unsigned long clk_rate = clk_get_rate(rp->clk);
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u64 div, tmp;
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if (clk_rate == 0)
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return -EINVAL;
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div = (u64)NSEC_PER_SEC * RCAR_PWM_MAX_CYCLE;
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tmp = (u64)period_ns * clk_rate + div - 1;
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tmp = div64_u64(tmp, div);
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div = ilog2(tmp - 1) + 1;
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return (div <= RCAR_PWM_MAX_DIVISION) ? div : -ERANGE;
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}
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static void rcar_pwm_set_clock_control(struct rcar_pwm_chip *rp,
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unsigned int div)
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{
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u32 value;
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value = rcar_pwm_read(rp, RCAR_PWMCR);
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value &= ~(RCAR_PWMCR_CCMD | RCAR_PWMCR_CC0_MASK);
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if (div & 1)
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value |= RCAR_PWMCR_CCMD;
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div >>= 1;
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value |= div << RCAR_PWMCR_CC0_SHIFT;
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rcar_pwm_write(rp, value, RCAR_PWMCR);
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}
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static int rcar_pwm_set_counter(struct rcar_pwm_chip *rp, int div, int duty_ns,
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int period_ns)
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{
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unsigned long long one_cycle, tmp; /* 0.01 nanoseconds */
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unsigned long clk_rate = clk_get_rate(rp->clk);
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u32 cyc, ph;
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one_cycle = (unsigned long long)NSEC_PER_SEC * 100ULL * (1 << div);
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do_div(one_cycle, clk_rate);
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tmp = period_ns * 100ULL;
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do_div(tmp, one_cycle);
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cyc = (tmp << RCAR_PWMCNT_CYC0_SHIFT) & RCAR_PWMCNT_CYC0_MASK;
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tmp = duty_ns * 100ULL;
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do_div(tmp, one_cycle);
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ph = tmp & RCAR_PWMCNT_PH0_MASK;
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/* Avoid prohibited setting */
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if (cyc == 0 || ph == 0)
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return -EINVAL;
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rcar_pwm_write(rp, cyc | ph, RCAR_PWMCNT);
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return 0;
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}
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static int rcar_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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return pm_runtime_get_sync(chip->dev);
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}
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static void rcar_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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pm_runtime_put(chip->dev);
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}
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static int rcar_pwm_enable(struct rcar_pwm_chip *rp)
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{
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u32 value;
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/* Don't enable the PWM device if CYC0 or PH0 is 0 */
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value = rcar_pwm_read(rp, RCAR_PWMCNT);
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if ((value & RCAR_PWMCNT_CYC0_MASK) == 0 ||
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(value & RCAR_PWMCNT_PH0_MASK) == 0)
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return -EINVAL;
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rcar_pwm_update(rp, RCAR_PWMCR_EN0, RCAR_PWMCR_EN0, RCAR_PWMCR);
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return 0;
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}
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static void rcar_pwm_disable(struct rcar_pwm_chip *rp)
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{
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rcar_pwm_update(rp, RCAR_PWMCR_EN0, 0, RCAR_PWMCR);
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}
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static int rcar_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
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const struct pwm_state *state)
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{
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struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip);
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int div, ret;
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/* This HW/driver only supports normal polarity */
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if (state->polarity != PWM_POLARITY_NORMAL)
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return -EINVAL;
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if (!state->enabled) {
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rcar_pwm_disable(rp);
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return 0;
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}
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div = rcar_pwm_get_clock_division(rp, state->period);
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if (div < 0)
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return div;
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rcar_pwm_update(rp, RCAR_PWMCR_SYNC, RCAR_PWMCR_SYNC, RCAR_PWMCR);
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ret = rcar_pwm_set_counter(rp, div, state->duty_cycle, state->period);
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if (!ret)
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rcar_pwm_set_clock_control(rp, div);
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/* The SYNC should be set to 0 even if rcar_pwm_set_counter failed */
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rcar_pwm_update(rp, RCAR_PWMCR_SYNC, 0, RCAR_PWMCR);
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if (!ret)
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ret = rcar_pwm_enable(rp);
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return ret;
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}
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static const struct pwm_ops rcar_pwm_ops = {
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.request = rcar_pwm_request,
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.free = rcar_pwm_free,
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.apply = rcar_pwm_apply,
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.owner = THIS_MODULE,
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};
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static int rcar_pwm_probe(struct platform_device *pdev)
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{
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struct rcar_pwm_chip *rcar_pwm;
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int ret;
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rcar_pwm = devm_kzalloc(&pdev->dev, sizeof(*rcar_pwm), GFP_KERNEL);
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if (rcar_pwm == NULL)
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return -ENOMEM;
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rcar_pwm->base = devm_platform_ioremap_resource(pdev, 0);
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if (IS_ERR(rcar_pwm->base))
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return PTR_ERR(rcar_pwm->base);
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rcar_pwm->clk = devm_clk_get(&pdev->dev, NULL);
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if (IS_ERR(rcar_pwm->clk)) {
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dev_err(&pdev->dev, "cannot get clock\n");
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return PTR_ERR(rcar_pwm->clk);
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}
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platform_set_drvdata(pdev, rcar_pwm);
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rcar_pwm->chip.dev = &pdev->dev;
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rcar_pwm->chip.ops = &rcar_pwm_ops;
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rcar_pwm->chip.base = -1;
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rcar_pwm->chip.npwm = 1;
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pm_runtime_enable(&pdev->dev);
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ret = pwmchip_add(&rcar_pwm->chip);
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if (ret < 0) {
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dev_err(&pdev->dev, "failed to register PWM chip: %d\n", ret);
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pm_runtime_disable(&pdev->dev);
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return ret;
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}
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return 0;
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}
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static int rcar_pwm_remove(struct platform_device *pdev)
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{
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struct rcar_pwm_chip *rcar_pwm = platform_get_drvdata(pdev);
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int ret;
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ret = pwmchip_remove(&rcar_pwm->chip);
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pm_runtime_disable(&pdev->dev);
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return ret;
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}
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static const struct of_device_id rcar_pwm_of_table[] = {
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{ .compatible = "renesas,pwm-rcar", },
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{ },
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};
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MODULE_DEVICE_TABLE(of, rcar_pwm_of_table);
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static struct platform_driver rcar_pwm_driver = {
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.probe = rcar_pwm_probe,
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.remove = rcar_pwm_remove,
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.driver = {
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.name = "pwm-rcar",
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.of_match_table = of_match_ptr(rcar_pwm_of_table),
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}
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};
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module_platform_driver(rcar_pwm_driver);
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MODULE_AUTHOR("Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>");
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MODULE_DESCRIPTION("Renesas PWM Timer Driver");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS("platform:pwm-rcar");
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