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![Uwe Kleine-König](/assets/img/avatar_default.png)
Since commit 5e5da1e9fb
("pwm: ab8500: Explicitly allocate pwm chip
base dynamically") all drivers use dynamic ID allocation explicitly. New
drivers are supposed to do the same, so remove support for driver
specified base IDs and drop all assignments in the low-level drivers.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
292 lines
7.5 KiB
C
292 lines
7.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
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* JZ4740 platform PWM support
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*
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* Limitations:
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* - The .apply callback doesn't complete the currently running period before
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* reconfiguring the hardware.
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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/gpio.h>
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#include <linux/kernel.h>
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#include <linux/mfd/ingenic-tcu.h>
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#include <linux/mfd/syscon.h>
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#include <linux/module.h>
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#include <linux/of_device.h>
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#include <linux/platform_device.h>
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#include <linux/pwm.h>
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#include <linux/regmap.h>
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struct soc_info {
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unsigned int num_pwms;
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};
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struct jz4740_pwm_chip {
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struct pwm_chip chip;
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struct regmap *map;
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};
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static inline struct jz4740_pwm_chip *to_jz4740(struct pwm_chip *chip)
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{
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return container_of(chip, struct jz4740_pwm_chip, chip);
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}
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static bool jz4740_pwm_can_use_chn(struct jz4740_pwm_chip *jz,
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unsigned int channel)
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{
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/* Enable all TCU channels for PWM use by default except channels 0/1 */
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u32 pwm_channels_mask = GENMASK(jz->chip.npwm - 1, 2);
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device_property_read_u32(jz->chip.dev->parent,
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"ingenic,pwm-channels-mask",
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&pwm_channels_mask);
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return !!(pwm_channels_mask & BIT(channel));
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}
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static int jz4740_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct jz4740_pwm_chip *jz = to_jz4740(chip);
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struct clk *clk;
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char name[16];
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int err;
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if (!jz4740_pwm_can_use_chn(jz, pwm->hwpwm))
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return -EBUSY;
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snprintf(name, sizeof(name), "timer%u", pwm->hwpwm);
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clk = clk_get(chip->dev, name);
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if (IS_ERR(clk))
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return dev_err_probe(chip->dev, PTR_ERR(clk),
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"Failed to get clock\n");
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err = clk_prepare_enable(clk);
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if (err < 0) {
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clk_put(clk);
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return err;
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}
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pwm_set_chip_data(pwm, clk);
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return 0;
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}
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static void jz4740_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct clk *clk = pwm_get_chip_data(pwm);
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clk_disable_unprepare(clk);
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clk_put(clk);
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}
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static int jz4740_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct jz4740_pwm_chip *jz = to_jz4740(chip);
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/* Enable PWM output */
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regmap_update_bits(jz->map, TCU_REG_TCSRc(pwm->hwpwm),
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TCU_TCSR_PWM_EN, TCU_TCSR_PWM_EN);
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/* Start counter */
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regmap_write(jz->map, TCU_REG_TESR, BIT(pwm->hwpwm));
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return 0;
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}
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static void jz4740_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct jz4740_pwm_chip *jz = to_jz4740(chip);
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/*
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* Set duty > period. This trick allows the TCU channels in TCU2 mode to
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* properly return to their init level.
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*/
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regmap_write(jz->map, TCU_REG_TDHRc(pwm->hwpwm), 0xffff);
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regmap_write(jz->map, TCU_REG_TDFRc(pwm->hwpwm), 0x0);
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/*
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* Disable PWM output.
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* In TCU2 mode (channel 1/2 on JZ4750+), this must be done before the
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* counter is stopped, while in TCU1 mode the order does not matter.
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*/
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regmap_update_bits(jz->map, TCU_REG_TCSRc(pwm->hwpwm),
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TCU_TCSR_PWM_EN, 0);
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/* Stop counter */
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regmap_write(jz->map, TCU_REG_TECR, BIT(pwm->hwpwm));
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}
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static int jz4740_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 jz4740_pwm_chip *jz4740 = to_jz4740(pwm->chip);
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unsigned long long tmp = 0xffffull * NSEC_PER_SEC;
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struct clk *clk = pwm_get_chip_data(pwm);
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unsigned long period, duty;
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long rate;
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int err;
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/*
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* Limit the clock to a maximum rate that still gives us a period value
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* which fits in 16 bits.
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*/
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do_div(tmp, state->period);
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/*
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* /!\ IMPORTANT NOTE:
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* -------------------
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* This code relies on the fact that clk_round_rate() will always round
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* down, which is not a valid assumption given by the clk API, but only
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* happens to be true with the clk drivers used for Ingenic SoCs.
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*
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* Right now, there is no alternative as the clk API does not have a
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* round-down function (and won't have one for a while), but if it ever
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* comes to light, a round-down function should be used instead.
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*/
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rate = clk_round_rate(clk, tmp);
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if (rate < 0) {
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dev_err(chip->dev, "Unable to round rate: %ld", rate);
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return rate;
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}
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/* Calculate period value */
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tmp = (unsigned long long)rate * state->period;
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do_div(tmp, NSEC_PER_SEC);
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period = tmp;
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/* Calculate duty value */
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tmp = (unsigned long long)rate * state->duty_cycle;
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do_div(tmp, NSEC_PER_SEC);
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duty = tmp;
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if (duty >= period)
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duty = period - 1;
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jz4740_pwm_disable(chip, pwm);
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err = clk_set_rate(clk, rate);
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if (err) {
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dev_err(chip->dev, "Unable to set rate: %d", err);
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return err;
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}
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/* Reset counter to 0 */
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regmap_write(jz4740->map, TCU_REG_TCNTc(pwm->hwpwm), 0);
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/* Set duty */
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regmap_write(jz4740->map, TCU_REG_TDHRc(pwm->hwpwm), duty);
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/* Set period */
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regmap_write(jz4740->map, TCU_REG_TDFRc(pwm->hwpwm), period);
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/* Set abrupt shutdown */
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regmap_update_bits(jz4740->map, TCU_REG_TCSRc(pwm->hwpwm),
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TCU_TCSR_PWM_SD, TCU_TCSR_PWM_SD);
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/*
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* Set polarity.
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*
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* The PWM starts in inactive state until the internal timer reaches the
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* duty value, then becomes active until the timer reaches the period
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* value. In theory, we should then use (period - duty) as the real duty
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* value, as a high duty value would otherwise result in the PWM pin
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* being inactive most of the time.
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*
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* Here, we don't do that, and instead invert the polarity of the PWM
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* when it is active. This trick makes the PWM start with its active
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* state instead of its inactive state.
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*/
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if ((state->polarity == PWM_POLARITY_NORMAL) ^ state->enabled)
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regmap_update_bits(jz4740->map, TCU_REG_TCSRc(pwm->hwpwm),
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TCU_TCSR_PWM_INITL_HIGH, 0);
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else
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regmap_update_bits(jz4740->map, TCU_REG_TCSRc(pwm->hwpwm),
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TCU_TCSR_PWM_INITL_HIGH,
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TCU_TCSR_PWM_INITL_HIGH);
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if (state->enabled)
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jz4740_pwm_enable(chip, pwm);
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return 0;
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}
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static const struct pwm_ops jz4740_pwm_ops = {
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.request = jz4740_pwm_request,
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.free = jz4740_pwm_free,
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.apply = jz4740_pwm_apply,
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.owner = THIS_MODULE,
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};
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static int jz4740_pwm_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct jz4740_pwm_chip *jz4740;
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const struct soc_info *info;
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info = device_get_match_data(dev);
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if (!info)
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return -EINVAL;
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jz4740 = devm_kzalloc(dev, sizeof(*jz4740), GFP_KERNEL);
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if (!jz4740)
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return -ENOMEM;
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jz4740->map = device_node_to_regmap(dev->parent->of_node);
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if (IS_ERR(jz4740->map)) {
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dev_err(dev, "regmap not found: %ld\n", PTR_ERR(jz4740->map));
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return PTR_ERR(jz4740->map);
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}
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jz4740->chip.dev = dev;
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jz4740->chip.ops = &jz4740_pwm_ops;
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jz4740->chip.npwm = info->num_pwms;
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jz4740->chip.of_xlate = of_pwm_xlate_with_flags;
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jz4740->chip.of_pwm_n_cells = 3;
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platform_set_drvdata(pdev, jz4740);
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return pwmchip_add(&jz4740->chip);
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}
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static int jz4740_pwm_remove(struct platform_device *pdev)
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{
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struct jz4740_pwm_chip *jz4740 = platform_get_drvdata(pdev);
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return pwmchip_remove(&jz4740->chip);
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}
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static const struct soc_info __maybe_unused jz4740_soc_info = {
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.num_pwms = 8,
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};
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static const struct soc_info __maybe_unused jz4725b_soc_info = {
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.num_pwms = 6,
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};
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#ifdef CONFIG_OF
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static const struct of_device_id jz4740_pwm_dt_ids[] = {
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{ .compatible = "ingenic,jz4740-pwm", .data = &jz4740_soc_info },
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{ .compatible = "ingenic,jz4725b-pwm", .data = &jz4725b_soc_info },
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{},
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};
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MODULE_DEVICE_TABLE(of, jz4740_pwm_dt_ids);
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#endif
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static struct platform_driver jz4740_pwm_driver = {
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.driver = {
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.name = "jz4740-pwm",
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.of_match_table = of_match_ptr(jz4740_pwm_dt_ids),
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},
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.probe = jz4740_pwm_probe,
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.remove = jz4740_pwm_remove,
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};
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module_platform_driver(jz4740_pwm_driver);
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MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
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MODULE_DESCRIPTION("Ingenic JZ4740 PWM driver");
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MODULE_ALIAS("platform:jz4740-pwm");
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MODULE_LICENSE("GPL");
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