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path: root/drivers/pwm/pwm-atmel-hlcdc.c
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Diffstat (limited to 'drivers/pwm/pwm-atmel-hlcdc.c')
-rw-r--r--drivers/pwm/pwm-atmel-hlcdc.c311
1 files changed, 311 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-atmel-hlcdc.c b/drivers/pwm/pwm-atmel-hlcdc.c
new file mode 100644
index 000000000..a43b2babc
--- /dev/null
+++ b/drivers/pwm/pwm-atmel-hlcdc.c
@@ -0,0 +1,311 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2014 Free Electrons
+ * Copyright (C) 2014 Atmel
+ *
+ * Author: Boris BREZILLON <boris.brezillon@free-electrons.com>
+ */
+
+#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_apply(struct pwm_chip *c, struct pwm_device *pwm,
+ const struct pwm_state *state)
+{
+ struct atmel_hlcdc_pwm *chip = to_atmel_hlcdc_pwm(c);
+ struct atmel_hlcdc *hlcdc = chip->hlcdc;
+ unsigned int status;
+ int ret;
+
+ if (state->enabled) {
+ struct clk *new_clk = hlcdc->slow_clk;
+ u64 pwmcval = state->duty_cycle * 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);
+ if (!clk_freq)
+ return -EINVAL;
+
+ 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 > state->period) {
+ new_clk = hlcdc->sys_clk;
+ clk_freq = clk_get_rate(new_clk);
+ if (!clk_freq)
+ return -EINVAL;
+
+ 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) >= state->period)
+ 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, state->period);
+
+ /*
+ * 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);
+
+ if (state->polarity == PWM_POLARITY_NORMAL)
+ pwmcfg |= ATMEL_HLCDC_PWMPOL;
+
+ ret = regmap_update_bits(hlcdc->regmap, ATMEL_HLCDC_CFG(6),
+ ATMEL_HLCDC_PWMCVAL_MASK |
+ ATMEL_HLCDC_PWMPS_MASK |
+ ATMEL_HLCDC_PWMPOL,
+ pwmcfg);
+ if (ret)
+ return ret;
+
+ ret = regmap_write(hlcdc->regmap, ATMEL_HLCDC_EN,
+ ATMEL_HLCDC_PWM);
+ if (ret)
+ return ret;
+
+ ret = regmap_read_poll_timeout(hlcdc->regmap, ATMEL_HLCDC_SR,
+ status,
+ status & ATMEL_HLCDC_PWM,
+ 10, 0);
+ if (ret)
+ return ret;
+ } else {
+ ret = regmap_write(hlcdc->regmap, ATMEL_HLCDC_DIS,
+ ATMEL_HLCDC_PWM);
+ if (ret)
+ return ret;
+
+ ret = regmap_read_poll_timeout(hlcdc->regmap, ATMEL_HLCDC_SR,
+ status,
+ !(status & ATMEL_HLCDC_PWM),
+ 10, 0);
+ if (ret)
+ return ret;
+
+ clk_disable_unprepare(chip->cur_clk);
+ chip->cur_clk = NULL;
+ }
+
+ return 0;
+}
+
+static const struct pwm_ops atmel_hlcdc_pwm_ops = {
+ .apply = atmel_hlcdc_pwm_apply,
+ .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,
+};
+
+#ifdef CONFIG_PM_SLEEP
+static int atmel_hlcdc_pwm_suspend(struct device *dev)
+{
+ struct atmel_hlcdc_pwm *chip = dev_get_drvdata(dev);
+
+ /* Keep the periph clock enabled if the PWM is still running. */
+ if (pwm_is_enabled(&chip->chip.pwms[0]))
+ clk_disable_unprepare(chip->hlcdc->periph_clk);
+
+ return 0;
+}
+
+static int atmel_hlcdc_pwm_resume(struct device *dev)
+{
+ struct atmel_hlcdc_pwm *chip = dev_get_drvdata(dev);
+ struct pwm_state state;
+ int ret;
+
+ pwm_get_state(&chip->chip.pwms[0], &state);
+
+ /* Re-enable the periph clock it was stopped during suspend. */
+ if (!state.enabled) {
+ ret = clk_prepare_enable(chip->hlcdc->periph_clk);
+ if (ret)
+ return ret;
+ }
+
+ return atmel_hlcdc_pwm_apply(&chip->chip, &chip->chip.pwms[0], &state);
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(atmel_hlcdc_pwm_pm_ops,
+ atmel_hlcdc_pwm_suspend, atmel_hlcdc_pwm_resume);
+
+static const struct of_device_id atmel_hlcdc_dt_ids[] = {
+ {
+ .compatible = "atmel,at91sam9n12-hlcdc",
+ /* 9n12 has same errata as 9x5 HLCDC PWM */
+ .data = &atmel_hlcdc_pwm_at91sam9x5_errata,
+ },
+ {
+ .compatible = "atmel,at91sam9x5-hlcdc",
+ .data = &atmel_hlcdc_pwm_at91sam9x5_errata,
+ },
+ {
+ .compatible = "atmel,sama5d2-hlcdc",
+ },
+ {
+ .compatible = "atmel,sama5d3-hlcdc",
+ .data = &atmel_hlcdc_pwm_sama5d3_errata,
+ },
+ {
+ .compatible = "atmel,sama5d4-hlcdc",
+ .data = &atmel_hlcdc_pwm_sama5d3_errata,
+ },
+ { .compatible = "microchip,sam9x60-hlcdc", },
+ { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, atmel_hlcdc_dt_ids);
+
+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.npwm = 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);
+
+ pwmchip_remove(&chip->chip);
+
+ 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,
+ .pm = &atmel_hlcdc_pwm_pm_ops,
+ },
+ .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");
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-27 09:05:22 +0000