23f373e6fe
Runtime PM callbacks can be run right after runtime PM is enabled, so make sure to set the driver data before that. This is unlikely to ever happen with the current driver, but it doesn't hurt to follow best practices anyway. Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
333 lines
8 KiB
C
333 lines
8 KiB
C
/*
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* ECAP PWM driver
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*
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* Copyright (C) 2012 Texas Instruments, Inc. - http://www.ti.com/
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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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)
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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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if (period_ns > NSEC_PER_SEC)
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return -ERANGE;
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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 (!pwm_is_enabled(pwm)) {
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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 (!pwm_is_enabled(pwm)) {
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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 void ecap_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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if (pwm_is_enabled(pwm)) {
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dev_warn(chip->dev, "Removing PWM device without disabling\n");
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pm_runtime_put_sync(chip->dev);
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}
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}
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static const struct pwm_ops ecap_pwm_ops = {
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.free = ecap_pwm_free,
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.config = ecap_pwm_config,
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.set_polarity = ecap_pwm_set_polarity,
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.enable = ecap_pwm_enable,
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.disable = ecap_pwm_disable,
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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 resource *r;
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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.of_xlate = of_pwm_xlate_with_flags;
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pc->chip.of_pwm_n_cells = 3;
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pc->chip.base = -1;
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pc->chip.npwm = 1;
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r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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pc->mmio_base = devm_ioremap_resource(&pdev->dev, r);
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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 = pwmchip_add(&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 int ecap_pwm_remove(struct platform_device *pdev)
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{
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struct ecap_pwm_chip *pc = platform_get_drvdata(pdev);
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pm_runtime_disable(&pdev->dev);
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return pwmchip_remove(&pc->chip);
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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 = 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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