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271 lines
6.2 KiB
271 lines
6.2 KiB
// 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.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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pwmchip_remove(&rcar_pwm->chip); |
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pm_runtime_disable(&pdev->dev); |
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return 0; |
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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 <[email protected]>"); |
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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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