This driver adds support for PWM driver on STM32 platform. The SoC have multiple instances of the hardware IP and each of them could have small differences: number of channels, complementary output, auto reload register size...
version 8: - fix comments done by Thierry on version 7
version 6: - change st,breakinput parameter to make it usuable for stm32f7 too.
version 4: - detect at probe time hardware capabilities - fix comments done on v2 and v3 - use PWM atomic ops
version 2: - only keep one comptatible - use DT parameters to discover hardware block configuration
Signed-off-by: Benjamin Gaignard benjamin.gaignard@st.com --- drivers/pwm/Kconfig | 9 ++ drivers/pwm/Makefile | 1 + drivers/pwm/pwm-stm32.c | 398 ++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 408 insertions(+) create mode 100644 drivers/pwm/pwm-stm32.c
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index f92dd41..2d0cfaa 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -397,6 +397,15 @@ config PWM_STI To compile this driver as a module, choose M here: the module will be called pwm-sti.
+config PWM_STM32 + tristate "STMicroelectronics STM32 PWM" + depends on MFD_STM32_TIMERS || COMPILE_TEST + help + Generic PWM framework driver for STM32 SoCs. + + To compile this driver as a module, choose M here: the module + will be called pwm-stm32. + config PWM_STMPE bool "STMPE expander PWM export" depends on MFD_STMPE diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index a48bdb5..346a83b 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -38,6 +38,7 @@ obj-$(CONFIG_PWM_ROCKCHIP) += pwm-rockchip.o obj-$(CONFIG_PWM_SAMSUNG) += pwm-samsung.o obj-$(CONFIG_PWM_SPEAR) += pwm-spear.o obj-$(CONFIG_PWM_STI) += pwm-sti.o +obj-$(CONFIG_PWM_STM32) += pwm-stm32.o obj-$(CONFIG_PWM_STMPE) += pwm-stmpe.o obj-$(CONFIG_PWM_SUN4I) += pwm-sun4i.o obj-$(CONFIG_PWM_TEGRA) += pwm-tegra.o diff --git a/drivers/pwm/pwm-stm32.c b/drivers/pwm/pwm-stm32.c new file mode 100644 index 0000000..3780afd --- /dev/null +++ b/drivers/pwm/pwm-stm32.c @@ -0,0 +1,398 @@ +/* + * Copyright (C) STMicroelectronics 2016 + * + * Author: Gerald Baeza gerald.baeza@st.com + * + * License terms: GNU General Public License (GPL), version 2 + * + * Inspired by timer-stm32.c from Maxime Coquelin + * pwm-atmel.c from Bo Shen + */ + +#include <linux/mfd/stm32-timers.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/pwm.h> + +#define CCMR_CHANNEL_SHIFT 8 +#define CCMR_CHANNEL_MASK 0xFF +#define MAX_BREAKINPUT 2 + +struct stm32_pwm { + struct pwm_chip chip; + struct device *dev; + struct clk *clk; + struct regmap *regmap; + u32 max_arr; + bool have_complementary_output; +}; + +struct stm32_breakinput { + u32 index; + u32 level; + u32 filter; +}; + +static inline struct stm32_pwm *to_stm32_pwm_dev(struct pwm_chip *chip) +{ + return container_of(chip, struct stm32_pwm, chip); +} + +static u32 active_channels(struct stm32_pwm *dev) +{ + u32 ccer; + + regmap_read(dev->regmap, TIM_CCER, &ccer); + + return ccer & TIM_CCER_CCXE; +} + +static int write_ccrx(struct stm32_pwm *dev, int ch, u32 value) +{ + switch (ch) { + case 0: + return regmap_write(dev->regmap, TIM_CCR1, value); + case 1: + return regmap_write(dev->regmap, TIM_CCR2, value); + case 2: + return regmap_write(dev->regmap, TIM_CCR3, value); + case 3: + return regmap_write(dev->regmap, TIM_CCR4, value); + } + return -EINVAL; +} + +static int stm32_pwm_config(struct stm32_pwm *priv, int ch, + int duty_ns, int period_ns) +{ + unsigned long long prd, div, dty; + unsigned int prescaler = 0; + u32 ccmr, mask, shift; + + /* Period and prescaler values depends on clock rate */ + div = (unsigned long long)clk_get_rate(priv->clk) * period_ns; + + do_div(div, NSEC_PER_SEC); + prd = div; + + while (div > priv->max_arr) { + prescaler++; + div = prd; + do_div(div, prescaler + 1); + } + + prd = div; + + if (prescaler > MAX_TIM_PSC) + return -EINVAL; + + /* + * All channels share the same prescaler and counter so when two + * channels are active at the same time we can't change them + */ + if (active_channels(priv) & ~(1 << ch * 4)) { + u32 psc, arr; + + regmap_read(priv->regmap, TIM_PSC, &psc); + regmap_read(priv->regmap, TIM_ARR, &arr); + + if ((psc != prescaler) || (arr != prd - 1)) + return -EBUSY; + } + + regmap_write(priv->regmap, TIM_PSC, prescaler); + regmap_write(priv->regmap, TIM_ARR, prd - 1); + regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, TIM_CR1_ARPE); + + /* Calculate the duty cycles */ + dty = prd * duty_ns; + do_div(dty, period_ns); + + write_ccrx(priv, ch, dty); + + /* Configure output mode */ + shift = (ch & 0x1) * CCMR_CHANNEL_SHIFT; + ccmr = (TIM_CCMR_PE | TIM_CCMR_M1) << shift; + mask = CCMR_CHANNEL_MASK << shift; + + if (ch < 2) + regmap_update_bits(priv->regmap, TIM_CCMR1, mask, ccmr); + else + regmap_update_bits(priv->regmap, TIM_CCMR2, mask, ccmr); + + regmap_update_bits(priv->regmap, TIM_BDTR, + TIM_BDTR_MOE | TIM_BDTR_AOE, + TIM_BDTR_MOE | TIM_BDTR_AOE); + + return 0; +} + +static int stm32_pwm_set_polarity(struct stm32_pwm *priv, int ch, + enum pwm_polarity polarity) +{ + u32 mask; + + mask = TIM_CCER_CC1P << (ch * 4); + if (priv->have_complementary_output) + mask |= TIM_CCER_CC1NP << (ch * 4); + + regmap_update_bits(priv->regmap, TIM_CCER, mask, + polarity == PWM_POLARITY_NORMAL ? 0 : mask); + + return 0; +} + +static int stm32_pwm_enable(struct stm32_pwm *priv, int ch) +{ + u32 mask; + int ret; + + ret = clk_enable(priv->clk); + if (ret) + return ret; + + /* Enable channel */ + mask = TIM_CCER_CC1E << (ch * 4); + if (priv->have_complementary_output) + mask |= TIM_CCER_CC1NE << (ch * 4); + + regmap_update_bits(priv->regmap, TIM_CCER, mask, mask); + + /* Make sure that registers are updated */ + regmap_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG); + + /* Enable controller */ + regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, TIM_CR1_CEN); + + return 0; +} + +static void stm32_pwm_disable(struct stm32_pwm *priv, int ch) +{ + u32 mask; + + /* Disable channel */ + mask = TIM_CCER_CC1E << (ch * 4); + if (priv->have_complementary_output) + mask |= TIM_CCER_CC1NE << (ch * 4); + + regmap_update_bits(priv->regmap, TIM_CCER, mask, 0); + + /* When all channels are disabled, we can disable the controller */ + if (!active_channels(priv)) + regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0); + + clk_disable(priv->clk); +} + +static int stm32_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, + struct pwm_state *state) +{ + struct pwm_state curstate; + bool enabled; + struct stm32_pwm *priv = to_stm32_pwm_dev(chip); + int ret; + + enabled = pwm->state.enabled; + + if (enabled && !state->enabled) { + stm32_pwm_disable(priv, pwm->hwpwm); + return 0; + } + + if (state->polarity != curstate.polarity) + stm32_pwm_set_polarity(priv, pwm->hwpwm, state->polarity); + + ret = stm32_pwm_config(priv, pwm->hwpwm, + state->duty_cycle, state->period); + if (ret) + return ret; + + if (!enabled && state->enabled) + ret = stm32_pwm_enable(priv, pwm->hwpwm); + + return ret; +} + +static const struct pwm_ops stm32pwm_ops = { + .owner = THIS_MODULE, + .apply = stm32_pwm_apply, +}; + +static int stm32_pwm_set_breakinput(struct stm32_pwm *priv, + int index, int level, int filter) +{ + u32 bke = (index == 0) ? TIM_BDTR_BKE : TIM_BDTR_BK2E; + int shift = (index == 0) ? TIM_BDTR_BKF_SHIFT : TIM_BDTR_BK2F_SHIFT; + u32 mask = (index == 0) ? TIM_BDTR_BKE | TIM_BDTR_BKP | TIM_BDTR_BKF + : TIM_BDTR_BK2E | TIM_BDTR_BK2P | TIM_BDTR_BK2F; + u32 bdtr = bke; + + /* + * The both bits could be set since only one will be wrote + * due to mask value. + */ + if (level) + bdtr |= TIM_BDTR_BKP | TIM_BDTR_BK2P; + + bdtr |= (filter & TIM_BDTR_BKF_MASK) << shift; + + regmap_update_bits(priv->regmap, TIM_BDTR, mask, bdtr); + + regmap_read(priv->regmap, TIM_BDTR, &bdtr); + + return (bdtr & bke) ? 0 : -EINVAL; +} + +static int stm32_pwm_apply_breakinputs(struct stm32_pwm *priv, + struct device_node *np) +{ + struct stm32_breakinput breakinput[MAX_BREAKINPUT]; + int nb, ret, i, array_size; + + nb = of_property_count_elems_of_size(np, "st,breakinput", + sizeof(struct stm32_breakinput)); + + /* + * Because "st,breakinput" parameter is optional do not make probe + * failed if it doesn't exist. + */ + if (nb <= 0) + return 0; + + if (nb > MAX_BREAKINPUT) + return -EINVAL; + + array_size = nb * sizeof(struct stm32_breakinput) / sizeof(u32); + ret = of_property_read_u32_array(np, "st,breakinput", + (u32 *)breakinput, array_size); + if (ret) + return ret; + + for (i = 0; i < nb && !ret; i++) { + ret = stm32_pwm_set_breakinput(priv, + breakinput[i].index, + breakinput[i].level, + breakinput[i].filter); + } + + return ret; +} + +static void stm32_pwm_detect_complementary(struct stm32_pwm *priv) +{ + u32 ccer; + + /* + * If complementary bit doesn't exist writing 1 will have no + * effect so we can detect it. + */ + regmap_update_bits(priv->regmap, + TIM_CCER, TIM_CCER_CC1NE, TIM_CCER_CC1NE); + regmap_read(priv->regmap, TIM_CCER, &ccer); + regmap_update_bits(priv->regmap, TIM_CCER, TIM_CCER_CC1NE, 0); + + priv->have_complementary_output = (ccer != 0); +} + +static int stm32_pwm_detect_channels(struct stm32_pwm *priv) +{ + u32 ccer; + int npwm = 0; + + /* + * If channels enable bits don't exist writing 1 will have no + * effect so we can detect and count them. + */ + regmap_update_bits(priv->regmap, + TIM_CCER, TIM_CCER_CCXE, TIM_CCER_CCXE); + regmap_read(priv->regmap, TIM_CCER, &ccer); + regmap_update_bits(priv->regmap, TIM_CCER, TIM_CCER_CCXE, 0); + + if (ccer & TIM_CCER_CC1E) + npwm++; + + if (ccer & TIM_CCER_CC2E) + npwm++; + + if (ccer & TIM_CCER_CC3E) + npwm++; + + if (ccer & TIM_CCER_CC4E) + npwm++; + + return npwm; +} + +static int stm32_pwm_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct device_node *np = dev->of_node; + struct stm32_timers *ddata = dev_get_drvdata(pdev->dev.parent); + struct stm32_pwm *priv; + int ret; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->regmap = ddata->regmap; + priv->clk = ddata->clk; + priv->max_arr = ddata->max_arr; + + if (!priv->regmap || !priv->clk) + return -EINVAL; + + ret = stm32_pwm_apply_breakinputs(priv, np); + if (ret) + return ret; + + stm32_pwm_detect_complementary(priv); + + priv->chip.base = -1; + priv->chip.dev = dev; + priv->chip.ops = &stm32pwm_ops; + priv->chip.npwm = stm32_pwm_detect_channels(priv); + + ret = pwmchip_add(&priv->chip); + if (ret < 0) + return ret; + + platform_set_drvdata(pdev, priv); + + return 0; +} + +static int stm32_pwm_remove(struct platform_device *pdev) +{ + struct stm32_pwm *priv = platform_get_drvdata(pdev); + unsigned int i; + + for (i = 0; i < priv->chip.npwm; i++) + pwm_disable(&priv->chip.pwms[i]); + + pwmchip_remove(&priv->chip); + + return 0; +} + +static const struct of_device_id stm32_pwm_of_match[] = { + { .compatible = "st,stm32-pwm", }, + { /* end node */ }, +}; +MODULE_DEVICE_TABLE(of, stm32_pwm_of_match); + +static struct platform_driver stm32_pwm_driver = { + .probe = stm32_pwm_probe, + .remove = stm32_pwm_remove, + .driver = { + .name = "stm32-pwm", + .of_match_table = stm32_pwm_of_match, + }, +}; +module_platform_driver(stm32_pwm_driver); + +MODULE_ALIAS("platform: stm32-pwm"); +MODULE_DESCRIPTION("STMicroelectronics STM32 PWM driver"); +MODULE_LICENSE("GPL v2");