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205 lines
4.9 KiB
205 lines
4.9 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* PWM framework driver for Cirrus Logic EP93xx |
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* |
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* Copyright (c) 2009 Matthieu Crapet <[email protected]> |
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* Copyright (c) 2009, 2013 H Hartley Sweeten <[email protected]> |
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* |
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* EP9301/02 have only one channel: |
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* platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14) |
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* |
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* EP9307 has only one channel: |
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* platform device ep93xx-pwm.0 - PWMOUT |
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* |
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* EP9312/15 have two channels: |
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* platform device ep93xx-pwm.0 - PWMOUT |
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* platform device ep93xx-pwm.1 - PWMOUT1 (EGPIO14) |
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*/ |
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#include <linux/module.h> |
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#include <linux/platform_device.h> |
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#include <linux/slab.h> |
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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/pwm.h> |
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#include <asm/div64.h> |
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#include <linux/soc/cirrus/ep93xx.h> /* for ep93xx_pwm_{acquire,release}_gpio() */ |
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#define EP93XX_PWMx_TERM_COUNT 0x00 |
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#define EP93XX_PWMx_DUTY_CYCLE 0x04 |
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#define EP93XX_PWMx_ENABLE 0x08 |
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#define EP93XX_PWMx_INVERT 0x0c |
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struct ep93xx_pwm { |
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void __iomem *base; |
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struct clk *clk; |
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struct pwm_chip chip; |
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}; |
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static inline struct ep93xx_pwm *to_ep93xx_pwm(struct pwm_chip *chip) |
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{ |
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return container_of(chip, struct ep93xx_pwm, chip); |
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} |
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static int ep93xx_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) |
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{ |
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struct platform_device *pdev = to_platform_device(chip->dev); |
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return ep93xx_pwm_acquire_gpio(pdev); |
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} |
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static void ep93xx_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) |
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{ |
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struct platform_device *pdev = to_platform_device(chip->dev); |
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ep93xx_pwm_release_gpio(pdev); |
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} |
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static int ep93xx_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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int ret; |
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struct ep93xx_pwm *ep93xx_pwm = to_ep93xx_pwm(chip); |
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bool enabled = state->enabled; |
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void __iomem *base = ep93xx_pwm->base; |
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unsigned long long c; |
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unsigned long period_cycles; |
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unsigned long duty_cycles; |
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unsigned long term; |
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if (state->polarity != pwm->state.polarity) { |
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if (enabled) { |
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writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_ENABLE); |
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clk_disable_unprepare(ep93xx_pwm->clk); |
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enabled = false; |
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} |
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/* |
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* The clock needs to be enabled to access the PWM registers. |
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* Polarity can only be changed when the PWM is disabled. |
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*/ |
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ret = clk_prepare_enable(ep93xx_pwm->clk); |
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if (ret) |
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return ret; |
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if (state->polarity == PWM_POLARITY_INVERSED) |
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writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_INVERT); |
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else |
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writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_INVERT); |
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clk_disable_unprepare(ep93xx_pwm->clk); |
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} |
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if (!state->enabled) { |
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if (enabled) { |
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writew(0x0, ep93xx_pwm->base + EP93XX_PWMx_ENABLE); |
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clk_disable_unprepare(ep93xx_pwm->clk); |
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} |
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return 0; |
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} |
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/* |
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* The clock needs to be enabled to access the PWM registers. |
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* Configuration can be changed at any time. |
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*/ |
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if (!pwm_is_enabled(pwm)) { |
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ret = clk_prepare_enable(ep93xx_pwm->clk); |
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if (ret) |
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return ret; |
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} |
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c = clk_get_rate(ep93xx_pwm->clk); |
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c *= state->period; |
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do_div(c, 1000000000); |
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period_cycles = c; |
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c = period_cycles; |
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c *= state->duty_cycle; |
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do_div(c, state->period); |
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duty_cycles = c; |
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if (period_cycles < 0x10000 && duty_cycles < 0x10000) { |
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term = readw(base + EP93XX_PWMx_TERM_COUNT); |
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/* Order is important if PWM is running */ |
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if (period_cycles > term) { |
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writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT); |
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writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE); |
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} else { |
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writew(duty_cycles, base + EP93XX_PWMx_DUTY_CYCLE); |
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writew(period_cycles, base + EP93XX_PWMx_TERM_COUNT); |
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} |
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ret = 0; |
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} else { |
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ret = -EINVAL; |
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} |
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if (!pwm_is_enabled(pwm)) |
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clk_disable_unprepare(ep93xx_pwm->clk); |
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if (ret) |
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return ret; |
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if (!enabled) { |
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ret = clk_prepare_enable(ep93xx_pwm->clk); |
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if (ret) |
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return ret; |
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writew(0x1, ep93xx_pwm->base + EP93XX_PWMx_ENABLE); |
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} |
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return 0; |
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} |
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static const struct pwm_ops ep93xx_pwm_ops = { |
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.request = ep93xx_pwm_request, |
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.free = ep93xx_pwm_free, |
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.apply = ep93xx_pwm_apply, |
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.owner = THIS_MODULE, |
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}; |
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static int ep93xx_pwm_probe(struct platform_device *pdev) |
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{ |
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struct ep93xx_pwm *ep93xx_pwm; |
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int ret; |
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ep93xx_pwm = devm_kzalloc(&pdev->dev, sizeof(*ep93xx_pwm), GFP_KERNEL); |
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if (!ep93xx_pwm) |
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return -ENOMEM; |
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ep93xx_pwm->base = devm_platform_ioremap_resource(pdev, 0); |
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if (IS_ERR(ep93xx_pwm->base)) |
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return PTR_ERR(ep93xx_pwm->base); |
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ep93xx_pwm->clk = devm_clk_get(&pdev->dev, "pwm_clk"); |
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if (IS_ERR(ep93xx_pwm->clk)) |
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return PTR_ERR(ep93xx_pwm->clk); |
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ep93xx_pwm->chip.dev = &pdev->dev; |
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ep93xx_pwm->chip.ops = &ep93xx_pwm_ops; |
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ep93xx_pwm->chip.npwm = 1; |
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ret = devm_pwmchip_add(&pdev->dev, &ep93xx_pwm->chip); |
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if (ret < 0) |
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return ret; |
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return 0; |
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} |
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static struct platform_driver ep93xx_pwm_driver = { |
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.driver = { |
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.name = "ep93xx-pwm", |
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}, |
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.probe = ep93xx_pwm_probe, |
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}; |
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module_platform_driver(ep93xx_pwm_driver); |
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MODULE_DESCRIPTION("Cirrus Logic EP93xx PWM driver"); |
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MODULE_AUTHOR("Matthieu Crapet <[email protected]>"); |
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MODULE_AUTHOR("H Hartley Sweeten <[email protected]>"); |
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MODULE_ALIAS("platform:ep93xx-pwm"); |
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MODULE_LICENSE("GPL");
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