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pwm: add support for atmel-hlcdc-pwm device
The HLCDC IP available in some Atmel SoCs (i.e. at91sam9x5, at91sam9n12 or sama5d3 families for instance) provides a PWM device. This driver add support for a PWM chip exposing a single PWM device (which will most likely be used to drive a backlight device). Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> Tested-by: Anthony Harivel <anthony.harivel@emtrion.de> Tested-by: Ludovic Desroches <ludovic.desroches@atmel.com> Acked-by: Thierry Reding <thierry.reding@gmail.com> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
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@ -50,6 +50,17 @@ config PWM_ATMEL
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To compile this driver as a module, choose M here: the module
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will be called pwm-atmel.
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config PWM_ATMEL_HLCDC_PWM
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tristate "Atmel HLCDC PWM support"
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depends on MFD_ATMEL_HLCDC
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help
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Generic PWM framework driver for the PWM output of the HLCDC
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(Atmel High-end LCD Controller). This PWM output is mainly used
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to control the LCD backlight.
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To compile this driver as a module, choose M here: the module
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will be called pwm-atmel-hlcdc.
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config PWM_ATMEL_TCB
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tristate "Atmel TC Block PWM support"
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depends on ATMEL_TCLIB && OF
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@ -2,6 +2,7 @@ obj-$(CONFIG_PWM) += core.o
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obj-$(CONFIG_PWM_SYSFS) += sysfs.o
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obj-$(CONFIG_PWM_AB8500) += pwm-ab8500.o
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obj-$(CONFIG_PWM_ATMEL) += pwm-atmel.o
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obj-$(CONFIG_PWM_ATMEL_HLCDC_PWM) += pwm-atmel-hlcdc.o
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obj-$(CONFIG_PWM_ATMEL_TCB) += pwm-atmel-tcb.o
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obj-$(CONFIG_PWM_BCM_KONA) += pwm-bcm-kona.o
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obj-$(CONFIG_PWM_BCM2835) += pwm-bcm2835.o
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259
drivers/pwm/pwm-atmel-hlcdc.c
Normal file
259
drivers/pwm/pwm-atmel-hlcdc.c
Normal file
@ -0,0 +1,259 @@
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/*
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* Copyright (C) 2014 Free Electrons
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* Copyright (C) 2014 Atmel
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*
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* Author: Boris BREZILLON <boris.brezillon@free-electrons.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/clk.h>
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#include <linux/delay.h>
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#include <linux/mfd/atmel-hlcdc.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/regmap.h>
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#define ATMEL_HLCDC_PWMCVAL_MASK GENMASK(15, 8)
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#define ATMEL_HLCDC_PWMCVAL(x) (((x) << 8) & ATMEL_HLCDC_PWMCVAL_MASK)
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#define ATMEL_HLCDC_PWMPOL BIT(4)
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#define ATMEL_HLCDC_PWMPS_MASK GENMASK(2, 0)
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#define ATMEL_HLCDC_PWMPS_MAX 0x6
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#define ATMEL_HLCDC_PWMPS(x) ((x) & ATMEL_HLCDC_PWMPS_MASK)
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struct atmel_hlcdc_pwm {
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struct pwm_chip chip;
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struct atmel_hlcdc *hlcdc;
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struct clk *cur_clk;
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};
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static inline struct atmel_hlcdc_pwm *to_atmel_hlcdc_pwm(struct pwm_chip *chip)
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{
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return container_of(chip, struct atmel_hlcdc_pwm, chip);
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}
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static int atmel_hlcdc_pwm_config(struct pwm_chip *c,
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struct pwm_device *pwm,
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int duty_ns, int period_ns)
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{
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struct atmel_hlcdc_pwm *chip = to_atmel_hlcdc_pwm(c);
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struct atmel_hlcdc *hlcdc = chip->hlcdc;
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struct clk *new_clk = hlcdc->slow_clk;
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u64 pwmcval = duty_ns * 256;
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unsigned long clk_freq;
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u64 clk_period_ns;
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u32 pwmcfg;
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int pres;
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clk_freq = clk_get_rate(new_clk);
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clk_period_ns = (u64)NSEC_PER_SEC * 256;
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do_div(clk_period_ns, clk_freq);
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if (clk_period_ns > period_ns) {
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new_clk = hlcdc->sys_clk;
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clk_freq = clk_get_rate(new_clk);
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clk_period_ns = (u64)NSEC_PER_SEC * 256;
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do_div(clk_period_ns, clk_freq);
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}
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for (pres = 0; pres <= ATMEL_HLCDC_PWMPS_MAX; pres++)
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if ((clk_period_ns << pres) >= period_ns)
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break;
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if (pres > ATMEL_HLCDC_PWMPS_MAX)
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return -EINVAL;
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pwmcfg = ATMEL_HLCDC_PWMPS(pres);
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if (new_clk != chip->cur_clk) {
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u32 gencfg = 0;
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int ret;
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ret = clk_prepare_enable(new_clk);
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if (ret)
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return ret;
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clk_disable_unprepare(chip->cur_clk);
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chip->cur_clk = new_clk;
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if (new_clk == hlcdc->sys_clk)
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gencfg = ATMEL_HLCDC_CLKPWMSEL;
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ret = regmap_update_bits(hlcdc->regmap, ATMEL_HLCDC_CFG(0),
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ATMEL_HLCDC_CLKPWMSEL, gencfg);
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if (ret)
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return ret;
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}
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do_div(pwmcval, period_ns);
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/*
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* The PWM duty cycle is configurable from 0/256 to 255/256 of the
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* period cycle. Hence we can't set a duty cycle occupying the
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* whole period cycle if we're asked to.
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* Set it to 255 if pwmcval is greater than 256.
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*/
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if (pwmcval > 255)
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pwmcval = 255;
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pwmcfg |= ATMEL_HLCDC_PWMCVAL(pwmcval);
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return regmap_update_bits(hlcdc->regmap, ATMEL_HLCDC_CFG(6),
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ATMEL_HLCDC_PWMCVAL_MASK |
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ATMEL_HLCDC_PWMPS_MASK,
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pwmcfg);
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}
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static int atmel_hlcdc_pwm_set_polarity(struct pwm_chip *c,
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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 atmel_hlcdc_pwm *chip = to_atmel_hlcdc_pwm(c);
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struct atmel_hlcdc *hlcdc = chip->hlcdc;
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u32 cfg = 0;
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if (polarity == PWM_POLARITY_NORMAL)
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cfg = ATMEL_HLCDC_PWMPOL;
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return regmap_update_bits(hlcdc->regmap, ATMEL_HLCDC_CFG(6),
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ATMEL_HLCDC_PWMPOL, cfg);
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}
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static int atmel_hlcdc_pwm_enable(struct pwm_chip *c, struct pwm_device *pwm)
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{
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struct atmel_hlcdc_pwm *chip = to_atmel_hlcdc_pwm(c);
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struct atmel_hlcdc *hlcdc = chip->hlcdc;
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u32 status;
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int ret;
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ret = regmap_write(hlcdc->regmap, ATMEL_HLCDC_EN, ATMEL_HLCDC_PWM);
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if (ret)
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return ret;
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while (true) {
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ret = regmap_read(hlcdc->regmap, ATMEL_HLCDC_SR, &status);
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if (ret)
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return ret;
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if ((status & ATMEL_HLCDC_PWM) != 0)
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break;
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usleep_range(1, 10);
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}
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return 0;
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}
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static void atmel_hlcdc_pwm_disable(struct pwm_chip *c,
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struct pwm_device *pwm)
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{
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struct atmel_hlcdc_pwm *chip = to_atmel_hlcdc_pwm(c);
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struct atmel_hlcdc *hlcdc = chip->hlcdc;
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u32 status;
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int ret;
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ret = regmap_write(hlcdc->regmap, ATMEL_HLCDC_DIS, ATMEL_HLCDC_PWM);
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if (ret)
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return;
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while (true) {
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ret = regmap_read(hlcdc->regmap, ATMEL_HLCDC_SR, &status);
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if (ret)
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return;
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if ((status & ATMEL_HLCDC_PWM) == 0)
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break;
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usleep_range(1, 10);
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}
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}
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static const struct pwm_ops atmel_hlcdc_pwm_ops = {
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.config = atmel_hlcdc_pwm_config,
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.set_polarity = atmel_hlcdc_pwm_set_polarity,
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.enable = atmel_hlcdc_pwm_enable,
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.disable = atmel_hlcdc_pwm_disable,
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.owner = THIS_MODULE,
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};
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static int atmel_hlcdc_pwm_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct atmel_hlcdc_pwm *chip;
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struct atmel_hlcdc *hlcdc;
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int ret;
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hlcdc = dev_get_drvdata(dev->parent);
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chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
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if (!chip)
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return -ENOMEM;
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ret = clk_prepare_enable(hlcdc->periph_clk);
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if (ret)
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return ret;
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chip->hlcdc = hlcdc;
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chip->chip.ops = &atmel_hlcdc_pwm_ops;
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chip->chip.dev = dev;
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chip->chip.base = -1;
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chip->chip.npwm = 1;
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chip->chip.of_xlate = of_pwm_xlate_with_flags;
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chip->chip.of_pwm_n_cells = 3;
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chip->chip.can_sleep = 1;
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ret = pwmchip_add(&chip->chip);
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if (ret) {
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clk_disable_unprepare(hlcdc->periph_clk);
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return ret;
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}
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platform_set_drvdata(pdev, chip);
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return 0;
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}
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static int atmel_hlcdc_pwm_remove(struct platform_device *pdev)
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{
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struct atmel_hlcdc_pwm *chip = platform_get_drvdata(pdev);
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int ret;
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ret = pwmchip_remove(&chip->chip);
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if (ret)
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return ret;
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clk_disable_unprepare(chip->hlcdc->periph_clk);
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return 0;
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}
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static const struct of_device_id atmel_hlcdc_pwm_dt_ids[] = {
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{ .compatible = "atmel,hlcdc-pwm" },
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{ /* sentinel */ },
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};
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static struct platform_driver atmel_hlcdc_pwm_driver = {
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.driver = {
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.name = "atmel-hlcdc-pwm",
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.of_match_table = atmel_hlcdc_pwm_dt_ids,
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},
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.probe = atmel_hlcdc_pwm_probe,
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.remove = atmel_hlcdc_pwm_remove,
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};
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module_platform_driver(atmel_hlcdc_pwm_driver);
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MODULE_ALIAS("platform:atmel-hlcdc-pwm");
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MODULE_AUTHOR("Boris Brezillon <boris.brezillon@free-electrons.com>");
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MODULE_DESCRIPTION("Atmel HLCDC PWM driver");
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MODULE_LICENSE("GPL v2");
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