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331 lines
8.0 KiB
331 lines
8.0 KiB
/* |
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* Marvell Berlin PWM driver |
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* |
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* Copyright (C) 2015 Marvell Technology Group Ltd. |
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* |
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* Author: Antoine Tenart <[email protected]> |
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* |
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* This file is licensed under the terms of the GNU General Public |
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* License version 2. This program is licensed "as is" without any |
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* warranty of any kind, whether express or implied. |
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*/ |
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#include <linux/clk.h> |
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#include <linux/io.h> |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/platform_device.h> |
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#include <linux/pwm.h> |
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#include <linux/slab.h> |
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#define BERLIN_PWM_EN 0x0 |
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#define BERLIN_PWM_ENABLE BIT(0) |
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#define BERLIN_PWM_CONTROL 0x4 |
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/* |
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* The prescaler claims to support 8 different moduli, configured using the |
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* low three bits of PWM_CONTROL. (Sequentially, they are 1, 4, 8, 16, 64, |
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* 256, 1024, and 4096.) However, the moduli from 4 to 1024 appear to be |
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* implemented by internally shifting TCNT left without adding additional |
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* bits. So, the max TCNT that actually works for a modulus of 4 is 0x3fff; |
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* for 8, 0x1fff; and so on. This means that those moduli are entirely |
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* useless, as we could just do the shift ourselves. The 4096 modulus is |
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* implemented with a real prescaler, so we do use that, but we treat it |
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* as a flag instead of pretending the modulus is actually configurable. |
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*/ |
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#define BERLIN_PWM_PRESCALE_4096 0x7 |
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#define BERLIN_PWM_INVERT_POLARITY BIT(3) |
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#define BERLIN_PWM_DUTY 0x8 |
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#define BERLIN_PWM_TCNT 0xc |
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#define BERLIN_PWM_MAX_TCNT 65535 |
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struct berlin_pwm_channel { |
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u32 enable; |
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u32 ctrl; |
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u32 duty; |
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u32 tcnt; |
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}; |
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struct berlin_pwm_chip { |
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struct pwm_chip chip; |
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struct clk *clk; |
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void __iomem *base; |
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}; |
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static inline struct berlin_pwm_chip *to_berlin_pwm_chip(struct pwm_chip *chip) |
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{ |
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return container_of(chip, struct berlin_pwm_chip, chip); |
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} |
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static inline u32 berlin_pwm_readl(struct berlin_pwm_chip *bpc, |
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unsigned int channel, unsigned long offset) |
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{ |
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return readl_relaxed(bpc->base + channel * 0x10 + offset); |
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} |
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static inline void berlin_pwm_writel(struct berlin_pwm_chip *bpc, |
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unsigned int channel, u32 value, |
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unsigned long offset) |
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{ |
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writel_relaxed(value, bpc->base + channel * 0x10 + offset); |
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} |
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static int berlin_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) |
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{ |
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struct berlin_pwm_channel *channel; |
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channel = kzalloc(sizeof(*channel), GFP_KERNEL); |
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if (!channel) |
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return -ENOMEM; |
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return pwm_set_chip_data(pwm, channel); |
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} |
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static void berlin_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) |
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{ |
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struct berlin_pwm_channel *channel = pwm_get_chip_data(pwm); |
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kfree(channel); |
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} |
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static int berlin_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, |
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u64 duty_ns, u64 period_ns) |
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{ |
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struct berlin_pwm_chip *bpc = to_berlin_pwm_chip(chip); |
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bool prescale_4096 = false; |
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u32 value, duty, period; |
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u64 cycles; |
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cycles = clk_get_rate(bpc->clk); |
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cycles *= period_ns; |
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do_div(cycles, NSEC_PER_SEC); |
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if (cycles > BERLIN_PWM_MAX_TCNT) { |
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prescale_4096 = true; |
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cycles >>= 12; // Prescaled by 4096 |
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if (cycles > BERLIN_PWM_MAX_TCNT) |
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return -ERANGE; |
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} |
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period = cycles; |
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cycles *= duty_ns; |
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do_div(cycles, period_ns); |
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duty = cycles; |
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value = berlin_pwm_readl(bpc, pwm->hwpwm, BERLIN_PWM_CONTROL); |
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if (prescale_4096) |
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value |= BERLIN_PWM_PRESCALE_4096; |
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else |
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value &= ~BERLIN_PWM_PRESCALE_4096; |
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berlin_pwm_writel(bpc, pwm->hwpwm, value, BERLIN_PWM_CONTROL); |
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berlin_pwm_writel(bpc, pwm->hwpwm, duty, BERLIN_PWM_DUTY); |
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berlin_pwm_writel(bpc, pwm->hwpwm, period, BERLIN_PWM_TCNT); |
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return 0; |
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} |
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static int berlin_pwm_set_polarity(struct pwm_chip *chip, |
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struct pwm_device *pwm, |
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enum pwm_polarity polarity) |
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{ |
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struct berlin_pwm_chip *bpc = to_berlin_pwm_chip(chip); |
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u32 value; |
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value = berlin_pwm_readl(bpc, pwm->hwpwm, BERLIN_PWM_CONTROL); |
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if (polarity == PWM_POLARITY_NORMAL) |
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value &= ~BERLIN_PWM_INVERT_POLARITY; |
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else |
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value |= BERLIN_PWM_INVERT_POLARITY; |
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berlin_pwm_writel(bpc, pwm->hwpwm, value, BERLIN_PWM_CONTROL); |
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return 0; |
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} |
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static int berlin_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) |
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{ |
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struct berlin_pwm_chip *bpc = to_berlin_pwm_chip(chip); |
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u32 value; |
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value = berlin_pwm_readl(bpc, pwm->hwpwm, BERLIN_PWM_EN); |
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value |= BERLIN_PWM_ENABLE; |
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berlin_pwm_writel(bpc, pwm->hwpwm, value, BERLIN_PWM_EN); |
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return 0; |
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} |
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static void berlin_pwm_disable(struct pwm_chip *chip, |
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struct pwm_device *pwm) |
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{ |
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struct berlin_pwm_chip *bpc = to_berlin_pwm_chip(chip); |
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u32 value; |
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value = berlin_pwm_readl(bpc, pwm->hwpwm, BERLIN_PWM_EN); |
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value &= ~BERLIN_PWM_ENABLE; |
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berlin_pwm_writel(bpc, pwm->hwpwm, value, BERLIN_PWM_EN); |
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} |
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static int berlin_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 err; |
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bool enabled = pwm->state.enabled; |
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if (state->polarity != pwm->state.polarity) { |
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if (enabled) { |
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berlin_pwm_disable(chip, pwm); |
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enabled = false; |
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} |
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err = berlin_pwm_set_polarity(chip, pwm, state->polarity); |
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if (err) |
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return err; |
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} |
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if (!state->enabled) { |
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if (enabled) |
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berlin_pwm_disable(chip, pwm); |
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return 0; |
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} |
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err = berlin_pwm_config(chip, pwm, state->duty_cycle, state->period); |
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if (err) |
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return err; |
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if (!enabled) |
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return berlin_pwm_enable(chip, pwm); |
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return 0; |
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} |
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static const struct pwm_ops berlin_pwm_ops = { |
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.request = berlin_pwm_request, |
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.free = berlin_pwm_free, |
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.apply = berlin_pwm_apply, |
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.owner = THIS_MODULE, |
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}; |
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static const struct of_device_id berlin_pwm_match[] = { |
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{ .compatible = "marvell,berlin-pwm" }, |
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{ }, |
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}; |
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MODULE_DEVICE_TABLE(of, berlin_pwm_match); |
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static int berlin_pwm_probe(struct platform_device *pdev) |
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{ |
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struct berlin_pwm_chip *bpc; |
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int ret; |
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bpc = devm_kzalloc(&pdev->dev, sizeof(*bpc), GFP_KERNEL); |
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if (!bpc) |
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return -ENOMEM; |
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bpc->base = devm_platform_ioremap_resource(pdev, 0); |
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if (IS_ERR(bpc->base)) |
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return PTR_ERR(bpc->base); |
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bpc->clk = devm_clk_get(&pdev->dev, NULL); |
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if (IS_ERR(bpc->clk)) |
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return PTR_ERR(bpc->clk); |
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ret = clk_prepare_enable(bpc->clk); |
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if (ret) |
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return ret; |
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bpc->chip.dev = &pdev->dev; |
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bpc->chip.ops = &berlin_pwm_ops; |
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bpc->chip.npwm = 4; |
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ret = pwmchip_add(&bpc->chip); |
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if (ret < 0) { |
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dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret); |
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clk_disable_unprepare(bpc->clk); |
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return ret; |
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} |
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platform_set_drvdata(pdev, bpc); |
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return 0; |
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} |
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static int berlin_pwm_remove(struct platform_device *pdev) |
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{ |
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struct berlin_pwm_chip *bpc = platform_get_drvdata(pdev); |
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pwmchip_remove(&bpc->chip); |
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clk_disable_unprepare(bpc->clk); |
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return 0; |
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} |
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#ifdef CONFIG_PM_SLEEP |
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static int berlin_pwm_suspend(struct device *dev) |
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{ |
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struct berlin_pwm_chip *bpc = dev_get_drvdata(dev); |
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unsigned int i; |
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for (i = 0; i < bpc->chip.npwm; i++) { |
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struct berlin_pwm_channel *channel; |
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channel = pwm_get_chip_data(&bpc->chip.pwms[i]); |
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if (!channel) |
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continue; |
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channel->enable = berlin_pwm_readl(bpc, i, BERLIN_PWM_ENABLE); |
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channel->ctrl = berlin_pwm_readl(bpc, i, BERLIN_PWM_CONTROL); |
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channel->duty = berlin_pwm_readl(bpc, i, BERLIN_PWM_DUTY); |
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channel->tcnt = berlin_pwm_readl(bpc, i, BERLIN_PWM_TCNT); |
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} |
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clk_disable_unprepare(bpc->clk); |
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return 0; |
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} |
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static int berlin_pwm_resume(struct device *dev) |
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{ |
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struct berlin_pwm_chip *bpc = dev_get_drvdata(dev); |
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unsigned int i; |
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int ret; |
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ret = clk_prepare_enable(bpc->clk); |
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if (ret) |
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return ret; |
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for (i = 0; i < bpc->chip.npwm; i++) { |
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struct berlin_pwm_channel *channel; |
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channel = pwm_get_chip_data(&bpc->chip.pwms[i]); |
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if (!channel) |
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continue; |
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berlin_pwm_writel(bpc, i, channel->ctrl, BERLIN_PWM_CONTROL); |
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berlin_pwm_writel(bpc, i, channel->duty, BERLIN_PWM_DUTY); |
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berlin_pwm_writel(bpc, i, channel->tcnt, BERLIN_PWM_TCNT); |
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berlin_pwm_writel(bpc, i, channel->enable, BERLIN_PWM_ENABLE); |
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} |
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return 0; |
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} |
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#endif |
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static SIMPLE_DEV_PM_OPS(berlin_pwm_pm_ops, berlin_pwm_suspend, |
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berlin_pwm_resume); |
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static struct platform_driver berlin_pwm_driver = { |
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.probe = berlin_pwm_probe, |
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.remove = berlin_pwm_remove, |
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.driver = { |
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.name = "berlin-pwm", |
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.of_match_table = berlin_pwm_match, |
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.pm = &berlin_pwm_pm_ops, |
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}, |
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}; |
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module_platform_driver(berlin_pwm_driver); |
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MODULE_AUTHOR("Antoine Tenart <[email protected]>"); |
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MODULE_DESCRIPTION("Marvell Berlin PWM driver"); |
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MODULE_LICENSE("GPL v2");
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