diff options
Diffstat (limited to 'drivers/pwm/pwm-atmel-hlcdc.c')
| -rw-r--r-- | drivers/pwm/pwm-atmel-hlcdc.c | 299 |
1 files changed, 299 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-atmel-hlcdc.c b/drivers/pwm/pwm-atmel-hlcdc.c new file mode 100644 index 000000000000..e7a785fadcdf --- /dev/null +++ b/drivers/pwm/pwm-atmel-hlcdc.c @@ -0,0 +1,299 @@ +/* + * Copyright (C) 2014 Free Electrons + * Copyright (C) 2014 Atmel + * + * Author: Boris BREZILLON <boris.brezillon@free-electrons.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/mfd/atmel-hlcdc.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/pwm.h> +#include <linux/regmap.h> + +#define ATMEL_HLCDC_PWMCVAL_MASK GENMASK(15, 8) +#define ATMEL_HLCDC_PWMCVAL(x) (((x) << 8) & ATMEL_HLCDC_PWMCVAL_MASK) +#define ATMEL_HLCDC_PWMPOL BIT(4) +#define ATMEL_HLCDC_PWMPS_MASK GENMASK(2, 0) +#define ATMEL_HLCDC_PWMPS_MAX 0x6 +#define ATMEL_HLCDC_PWMPS(x) ((x) & ATMEL_HLCDC_PWMPS_MASK) + +struct atmel_hlcdc_pwm_errata { + bool slow_clk_erratum; + bool div1_clk_erratum; +}; + +struct atmel_hlcdc_pwm { + struct pwm_chip chip; + struct atmel_hlcdc *hlcdc; + struct clk *cur_clk; + const struct atmel_hlcdc_pwm_errata *errata; +}; + +static inline struct atmel_hlcdc_pwm *to_atmel_hlcdc_pwm(struct pwm_chip *chip) +{ + return container_of(chip, struct atmel_hlcdc_pwm, chip); +} + +static int atmel_hlcdc_pwm_config(struct pwm_chip *c, + struct pwm_device *pwm, + int duty_ns, int period_ns) +{ + struct atmel_hlcdc_pwm *chip = to_atmel_hlcdc_pwm(c); + struct atmel_hlcdc *hlcdc = chip->hlcdc; + struct clk *new_clk = hlcdc->slow_clk; + u64 pwmcval = duty_ns * 256; + unsigned long clk_freq; + u64 clk_period_ns; + u32 pwmcfg; + int pres; + + if (!chip->errata || !chip->errata->slow_clk_erratum) { + clk_freq = clk_get_rate(new_clk); + clk_period_ns = (u64)NSEC_PER_SEC * 256; + do_div(clk_period_ns, clk_freq); + } + + /* Errata: cannot use slow clk on some IP revisions */ + if ((chip->errata && chip->errata->slow_clk_erratum) || + clk_period_ns > period_ns) { + new_clk = hlcdc->sys_clk; + clk_freq = clk_get_rate(new_clk); + clk_period_ns = (u64)NSEC_PER_SEC * 256; + do_div(clk_period_ns, clk_freq); + } + + for (pres = 0; pres <= ATMEL_HLCDC_PWMPS_MAX; pres++) { + /* Errata: cannot divide by 1 on some IP revisions */ + if (!pres && chip->errata && chip->errata->div1_clk_erratum) + continue; + + if ((clk_period_ns << pres) >= period_ns) + break; + } + + if (pres > ATMEL_HLCDC_PWMPS_MAX) + return -EINVAL; + + pwmcfg = ATMEL_HLCDC_PWMPS(pres); + + if (new_clk != chip->cur_clk) { + u32 gencfg = 0; + int ret; + + ret = clk_prepare_enable(new_clk); + if (ret) + return ret; + + clk_disable_unprepare(chip->cur_clk); + chip->cur_clk = new_clk; + + if (new_clk == hlcdc->sys_clk) + gencfg = ATMEL_HLCDC_CLKPWMSEL; + + ret = regmap_update_bits(hlcdc->regmap, ATMEL_HLCDC_CFG(0), + ATMEL_HLCDC_CLKPWMSEL, gencfg); + if (ret) + return ret; + } + + do_div(pwmcval, period_ns); + + /* + * The PWM duty cycle is configurable from 0/256 to 255/256 of the + * period cycle. Hence we can't set a duty cycle occupying the + * whole period cycle if we're asked to. + * Set it to 255 if pwmcval is greater than 256. + */ + if (pwmcval > 255) + pwmcval = 255; + + pwmcfg |= ATMEL_HLCDC_PWMCVAL(pwmcval); + + return regmap_update_bits(hlcdc->regmap, ATMEL_HLCDC_CFG(6), + ATMEL_HLCDC_PWMCVAL_MASK | + ATMEL_HLCDC_PWMPS_MASK, + pwmcfg); +} + +static int atmel_hlcdc_pwm_set_polarity(struct pwm_chip *c, + struct pwm_device *pwm, + enum pwm_polarity polarity) +{ + struct atmel_hlcdc_pwm *chip = to_atmel_hlcdc_pwm(c); + struct atmel_hlcdc *hlcdc = chip->hlcdc; + u32 cfg = 0; + + if (polarity == PWM_POLARITY_NORMAL) + cfg = ATMEL_HLCDC_PWMPOL; + + return regmap_update_bits(hlcdc->regmap, ATMEL_HLCDC_CFG(6), + ATMEL_HLCDC_PWMPOL, cfg); +} + +static int atmel_hlcdc_pwm_enable(struct pwm_chip *c, struct pwm_device *pwm) +{ + struct atmel_hlcdc_pwm *chip = to_atmel_hlcdc_pwm(c); + struct atmel_hlcdc *hlcdc = chip->hlcdc; + u32 status; + int ret; + + ret = regmap_write(hlcdc->regmap, ATMEL_HLCDC_EN, ATMEL_HLCDC_PWM); + if (ret) + return ret; + + while (true) { + ret = regmap_read(hlcdc->regmap, ATMEL_HLCDC_SR, &status); + if (ret) + return ret; + + if ((status & ATMEL_HLCDC_PWM) != 0) + break; + + usleep_range(1, 10); + } + + return 0; +} + +static void atmel_hlcdc_pwm_disable(struct pwm_chip *c, + struct pwm_device *pwm) +{ + struct atmel_hlcdc_pwm *chip = to_atmel_hlcdc_pwm(c); + struct atmel_hlcdc *hlcdc = chip->hlcdc; + u32 status; + int ret; + + ret = regmap_write(hlcdc->regmap, ATMEL_HLCDC_DIS, ATMEL_HLCDC_PWM); + if (ret) + return; + + while (true) { + ret = regmap_read(hlcdc->regmap, ATMEL_HLCDC_SR, &status); + if (ret) + return; + + if ((status & ATMEL_HLCDC_PWM) == 0) + break; + + usleep_range(1, 10); + } +} + +static const struct pwm_ops atmel_hlcdc_pwm_ops = { + .config = atmel_hlcdc_pwm_config, + .set_polarity = atmel_hlcdc_pwm_set_polarity, + .enable = atmel_hlcdc_pwm_enable, + .disable = atmel_hlcdc_pwm_disable, + .owner = THIS_MODULE, +}; + +static const struct atmel_hlcdc_pwm_errata atmel_hlcdc_pwm_at91sam9x5_errata = { + .slow_clk_erratum = true, +}; + +static const struct atmel_hlcdc_pwm_errata atmel_hlcdc_pwm_sama5d3_errata = { + .div1_clk_erratum = true, +}; + +static const struct of_device_id atmel_hlcdc_dt_ids[] = { + { + .compatible = "atmel,at91sam9x5-hlcdc", + .data = &atmel_hlcdc_pwm_at91sam9x5_errata, + }, + { + .compatible = "atmel,sama5d3-hlcdc", + .data = &atmel_hlcdc_pwm_sama5d3_errata, + }, + { /* sentinel */ }, +}; + +static int atmel_hlcdc_pwm_probe(struct platform_device *pdev) +{ + const struct of_device_id *match; + struct device *dev = &pdev->dev; + struct atmel_hlcdc_pwm *chip; + struct atmel_hlcdc *hlcdc; + int ret; + + hlcdc = dev_get_drvdata(dev->parent); + + chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL); + if (!chip) + return -ENOMEM; + + ret = clk_prepare_enable(hlcdc->periph_clk); + if (ret) + return ret; + + match = of_match_node(atmel_hlcdc_dt_ids, dev->parent->of_node); + if (match) + chip->errata = match->data; + + chip->hlcdc = hlcdc; + chip->chip.ops = &atmel_hlcdc_pwm_ops; + chip->chip.dev = dev; + chip->chip.base = -1; + chip->chip.npwm = 1; + chip->chip.of_xlate = of_pwm_xlate_with_flags; + chip->chip.of_pwm_n_cells = 3; + chip->chip.can_sleep = 1; + + ret = pwmchip_add(&chip->chip); + if (ret) { + clk_disable_unprepare(hlcdc->periph_clk); + return ret; + } + + platform_set_drvdata(pdev, chip); + + return 0; +} + +static int atmel_hlcdc_pwm_remove(struct platform_device *pdev) +{ + struct atmel_hlcdc_pwm *chip = platform_get_drvdata(pdev); + int ret; + + ret = pwmchip_remove(&chip->chip); + if (ret) + return ret; + + clk_disable_unprepare(chip->hlcdc->periph_clk); + + return 0; +} + +static const struct of_device_id atmel_hlcdc_pwm_dt_ids[] = { + { .compatible = "atmel,hlcdc-pwm" }, + { /* sentinel */ }, +}; + +static struct platform_driver atmel_hlcdc_pwm_driver = { + .driver = { + .name = "atmel-hlcdc-pwm", + .of_match_table = atmel_hlcdc_pwm_dt_ids, + }, + .probe = atmel_hlcdc_pwm_probe, + .remove = atmel_hlcdc_pwm_remove, +}; +module_platform_driver(atmel_hlcdc_pwm_driver); + +MODULE_ALIAS("platform:atmel-hlcdc-pwm"); +MODULE_AUTHOR("Boris Brezillon <boris.brezillon@free-electrons.com>"); +MODULE_DESCRIPTION("Atmel HLCDC PWM driver"); +MODULE_LICENSE("GPL v2"); |