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dc75f6bc5b
The .remove() callback for a platform driver returns an int which makes many driver authors wrongly assume it's possible to do error handling by returning an error code. However the value returned is (mostly) ignored and this typically results in resource leaks. To improve here there is a quest to make the remove callback return void. In the first step of this quest all drivers are converted to .remove_new() which already returns void. Trivially convert this driver from always returning zero in the remove callback to the void returning variant. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
334 lines
7.5 KiB
C
334 lines
7.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* ECAP PWM driver
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*
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* Copyright (C) 2012 Texas Instruments, Inc. - https://www.ti.com/
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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/io.h>
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#include <linux/err.h>
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#include <linux/clk.h>
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#include <linux/pm_runtime.h>
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#include <linux/pwm.h>
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#include <linux/of_device.h>
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/* ECAP registers and bits definitions */
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#define CAP1 0x08
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#define CAP2 0x0C
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#define CAP3 0x10
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#define CAP4 0x14
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#define ECCTL2 0x2A
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#define ECCTL2_APWM_POL_LOW BIT(10)
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#define ECCTL2_APWM_MODE BIT(9)
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#define ECCTL2_SYNC_SEL_DISA (BIT(7) | BIT(6))
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#define ECCTL2_TSCTR_FREERUN BIT(4)
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struct ecap_context {
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u32 cap3;
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u32 cap4;
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u16 ecctl2;
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};
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struct ecap_pwm_chip {
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struct pwm_chip chip;
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unsigned int clk_rate;
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void __iomem *mmio_base;
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struct ecap_context ctx;
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};
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static inline struct ecap_pwm_chip *to_ecap_pwm_chip(struct pwm_chip *chip)
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{
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return container_of(chip, struct ecap_pwm_chip, chip);
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}
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/*
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* period_ns = 10^9 * period_cycles / PWM_CLK_RATE
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* duty_ns = 10^9 * duty_cycles / PWM_CLK_RATE
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*/
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static int ecap_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
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int duty_ns, int period_ns, int enabled)
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{
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struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
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u32 period_cycles, duty_cycles;
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unsigned long long c;
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u16 value;
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c = pc->clk_rate;
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c = c * period_ns;
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do_div(c, NSEC_PER_SEC);
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period_cycles = (u32)c;
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if (period_cycles < 1) {
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period_cycles = 1;
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duty_cycles = 1;
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} else {
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c = pc->clk_rate;
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c = c * duty_ns;
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do_div(c, NSEC_PER_SEC);
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duty_cycles = (u32)c;
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}
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pm_runtime_get_sync(pc->chip.dev);
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value = readw(pc->mmio_base + ECCTL2);
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/* Configure APWM mode & disable sync option */
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value |= ECCTL2_APWM_MODE | ECCTL2_SYNC_SEL_DISA;
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writew(value, pc->mmio_base + ECCTL2);
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if (!enabled) {
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/* Update active registers if not running */
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writel(duty_cycles, pc->mmio_base + CAP2);
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writel(period_cycles, pc->mmio_base + CAP1);
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} else {
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/*
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* Update shadow registers to configure period and
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* compare values. This helps current PWM period to
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* complete on reconfiguring
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*/
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writel(duty_cycles, pc->mmio_base + CAP4);
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writel(period_cycles, pc->mmio_base + CAP3);
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}
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if (!enabled) {
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value = readw(pc->mmio_base + ECCTL2);
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/* Disable APWM mode to put APWM output Low */
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value &= ~ECCTL2_APWM_MODE;
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writew(value, pc->mmio_base + ECCTL2);
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}
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pm_runtime_put_sync(pc->chip.dev);
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return 0;
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}
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static int ecap_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 ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
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u16 value;
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pm_runtime_get_sync(pc->chip.dev);
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value = readw(pc->mmio_base + ECCTL2);
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if (polarity == PWM_POLARITY_INVERSED)
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/* Duty cycle defines LOW period of PWM */
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value |= ECCTL2_APWM_POL_LOW;
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else
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/* Duty cycle defines HIGH period of PWM */
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value &= ~ECCTL2_APWM_POL_LOW;
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writew(value, pc->mmio_base + ECCTL2);
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pm_runtime_put_sync(pc->chip.dev);
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return 0;
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}
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static int ecap_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
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u16 value;
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/* Leave clock enabled on enabling PWM */
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pm_runtime_get_sync(pc->chip.dev);
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/*
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* Enable 'Free run Time stamp counter mode' to start counter
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* and 'APWM mode' to enable APWM output
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*/
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value = readw(pc->mmio_base + ECCTL2);
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value |= ECCTL2_TSCTR_FREERUN | ECCTL2_APWM_MODE;
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writew(value, pc->mmio_base + ECCTL2);
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return 0;
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}
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static void ecap_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
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u16 value;
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/*
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* Disable 'Free run Time stamp counter mode' to stop counter
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* and 'APWM mode' to put APWM output to low
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*/
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value = readw(pc->mmio_base + ECCTL2);
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value &= ~(ECCTL2_TSCTR_FREERUN | ECCTL2_APWM_MODE);
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writew(value, pc->mmio_base + ECCTL2);
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/* Disable clock on PWM disable */
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pm_runtime_put_sync(pc->chip.dev);
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}
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static int ecap_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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int enabled = pwm->state.enabled;
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if (state->polarity != pwm->state.polarity) {
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if (enabled) {
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ecap_pwm_disable(chip, pwm);
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enabled = false;
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}
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err = ecap_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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ecap_pwm_disable(chip, pwm);
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return 0;
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}
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if (state->period > NSEC_PER_SEC)
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return -ERANGE;
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err = ecap_pwm_config(chip, pwm, state->duty_cycle,
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state->period, enabled);
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if (err)
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return err;
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if (!enabled)
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return ecap_pwm_enable(chip, pwm);
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return 0;
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}
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static const struct pwm_ops ecap_pwm_ops = {
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.apply = ecap_pwm_apply,
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.owner = THIS_MODULE,
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};
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static const struct of_device_id ecap_of_match[] = {
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{ .compatible = "ti,am3352-ecap" },
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{ .compatible = "ti,am33xx-ecap" },
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{},
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};
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MODULE_DEVICE_TABLE(of, ecap_of_match);
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static int ecap_pwm_probe(struct platform_device *pdev)
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{
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struct device_node *np = pdev->dev.of_node;
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struct ecap_pwm_chip *pc;
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struct clk *clk;
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int ret;
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pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
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if (!pc)
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return -ENOMEM;
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clk = devm_clk_get(&pdev->dev, "fck");
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if (IS_ERR(clk)) {
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if (of_device_is_compatible(np, "ti,am33xx-ecap")) {
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dev_warn(&pdev->dev, "Binding is obsolete.\n");
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clk = devm_clk_get(pdev->dev.parent, "fck");
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}
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}
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if (IS_ERR(clk)) {
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dev_err(&pdev->dev, "failed to get clock\n");
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return PTR_ERR(clk);
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}
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pc->clk_rate = clk_get_rate(clk);
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if (!pc->clk_rate) {
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dev_err(&pdev->dev, "failed to get clock rate\n");
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return -EINVAL;
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}
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pc->chip.dev = &pdev->dev;
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pc->chip.ops = &ecap_pwm_ops;
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pc->chip.npwm = 1;
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pc->mmio_base = devm_platform_ioremap_resource(pdev, 0);
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if (IS_ERR(pc->mmio_base))
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return PTR_ERR(pc->mmio_base);
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ret = devm_pwmchip_add(&pdev->dev, &pc->chip);
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if (ret < 0) {
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dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
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return ret;
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}
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platform_set_drvdata(pdev, pc);
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pm_runtime_enable(&pdev->dev);
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return 0;
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}
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static void ecap_pwm_remove(struct platform_device *pdev)
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{
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pm_runtime_disable(&pdev->dev);
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}
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#ifdef CONFIG_PM_SLEEP
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static void ecap_pwm_save_context(struct ecap_pwm_chip *pc)
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{
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pm_runtime_get_sync(pc->chip.dev);
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pc->ctx.ecctl2 = readw(pc->mmio_base + ECCTL2);
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pc->ctx.cap4 = readl(pc->mmio_base + CAP4);
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pc->ctx.cap3 = readl(pc->mmio_base + CAP3);
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pm_runtime_put_sync(pc->chip.dev);
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}
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static void ecap_pwm_restore_context(struct ecap_pwm_chip *pc)
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{
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writel(pc->ctx.cap3, pc->mmio_base + CAP3);
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writel(pc->ctx.cap4, pc->mmio_base + CAP4);
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writew(pc->ctx.ecctl2, pc->mmio_base + ECCTL2);
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}
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static int ecap_pwm_suspend(struct device *dev)
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{
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struct ecap_pwm_chip *pc = dev_get_drvdata(dev);
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struct pwm_device *pwm = pc->chip.pwms;
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ecap_pwm_save_context(pc);
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/* Disable explicitly if PWM is running */
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if (pwm_is_enabled(pwm))
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pm_runtime_put_sync(dev);
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return 0;
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}
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static int ecap_pwm_resume(struct device *dev)
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{
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struct ecap_pwm_chip *pc = dev_get_drvdata(dev);
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struct pwm_device *pwm = pc->chip.pwms;
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/* Enable explicitly if PWM was running */
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if (pwm_is_enabled(pwm))
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pm_runtime_get_sync(dev);
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ecap_pwm_restore_context(pc);
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return 0;
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}
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#endif
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static SIMPLE_DEV_PM_OPS(ecap_pwm_pm_ops, ecap_pwm_suspend, ecap_pwm_resume);
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static struct platform_driver ecap_pwm_driver = {
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.driver = {
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.name = "ecap",
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.of_match_table = ecap_of_match,
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.pm = &ecap_pwm_pm_ops,
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},
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.probe = ecap_pwm_probe,
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.remove_new = ecap_pwm_remove,
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};
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module_platform_driver(ecap_pwm_driver);
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MODULE_DESCRIPTION("ECAP PWM driver");
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MODULE_AUTHOR("Texas Instruments");
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MODULE_LICENSE("GPL");
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