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Message-Id: <1481027929-13704-5-git-send-email-benjamin.gaignard@st.com>
Date: Tue, 6 Dec 2016 13:38:46 +0100
From: Benjamin Gaignard <benjamin.gaignard@...aro.org>
To: lee.jones@...aro.org, robh+dt@...nel.org, mark.rutland@....com,
alexandre.torgue@...com, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org, thierry.reding@...il.com,
linux-pwm@...r.kernel.org, jic23@...nel.org, knaack.h@....de,
lars@...afoo.de, pmeerw@...erw.net, linux-iio@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org
Cc: fabrice.gasnier@...com, gerald.baeza@...com,
arnaud.pouliquen@...com, linus.walleij@...aro.org,
linaro-kernel@...ts.linaro.org, benjamin.gaignard@...aro.org,
Benjamin Gaignard <benjamin.gaignard@...com>
Subject: [PATCH v4 4/7] PWM: add PWM driver for STM32 plaftorm
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 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@...com>
---
drivers/pwm/Kconfig | 11 ++
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-stm32.c | 363 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 375 insertions(+)
create mode 100644 drivers/pwm/pwm-stm32.c
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index bf01288..95c9f04 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -388,6 +388,17 @@ config PWM_STI
To compile this driver as a module, choose M here: the module
will be called pwm-sti.
+config PWM_STM32
+ bool "STMicroelectronics STM32 PWM"
+ depends on ARCH_STM32 || COMPILE_TEST
+ depends on OF
+ depends on MFD_STM32_GP_TIMER
+ 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 1194c54..5aa9308 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -37,6 +37,7 @@ 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..319fd77
--- /dev/null
+++ b/drivers/pwm/pwm-stm32.c
@@ -0,0 +1,363 @@
+/*
+ * Copyright (C) STMicroelectronics 2016
+ *
+ * Author: Gerald Baeza <gerald.baeza@...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/module.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/of.h>
+
+#include <linux/mfd/stm32-gptimer.h>
+
+#define CCMR_CHANNEL_SHIFT 8
+#define CCMR_CHANNEL_MASK 0xFF
+
+struct stm32_pwm {
+ struct pwm_chip chip;
+ struct device *dev;
+ struct clk *clk;
+ struct regmap *regmap;
+ unsigned int caps;
+ unsigned int npwm;
+ u32 breakinput_polarity;
+ u32 max_arr;
+ bool have_complementary_output;
+ bool have_breakinput;
+ bool use_breakinput;
+};
+
+#define to_stm32_pwm_dev(x) 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, struct pwm_device *pwm,
+ u32 value)
+{
+ switch (pwm->hwpwm) {
+ 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 pwm_chip *chip, struct pwm_device *pwm,
+ int duty_ns, int period_ns)
+{
+ struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
+ unsigned long long prd, div, dty;
+ unsigned int prescaler = 0;
+ u32 ccmr, mask, shift, bdtr;
+
+ /* 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) {
+ dev_err(chip->dev, "prescaler exceeds the maximum value\n");
+ return -EINVAL;
+ }
+
+ /*
+ * All channels share the same prescaler and counter so when two
+ * channels are active at the same we can't change them
+ */
+ if (active_channels(priv) & ~(1 << pwm->hwpwm * 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, pwm, dty);
+
+ /* Configure output mode */
+ shift = (pwm->hwpwm & 0x1) * CCMR_CHANNEL_SHIFT;
+ ccmr = (TIM_CCMR_PE | TIM_CCMR_M1) << shift;
+ mask = CCMR_CHANNEL_MASK << shift;
+
+ if (pwm->hwpwm < 2)
+ regmap_update_bits(priv->regmap, TIM_CCMR1, mask, ccmr);
+ else
+ regmap_update_bits(priv->regmap, TIM_CCMR2, mask, ccmr);
+
+ if (!priv->have_breakinput)
+ return 0;
+
+ bdtr = TIM_BDTR_MOE | TIM_BDTR_AOE;
+
+ if (priv->use_breakinput)
+ bdtr |= TIM_BDTR_BKE;
+
+ if (priv->breakinput_polarity)
+ bdtr |= TIM_BDTR_BKP;
+
+ regmap_update_bits(priv->regmap, TIM_BDTR,
+ TIM_BDTR_MOE | TIM_BDTR_AOE |
+ TIM_BDTR_BKP | TIM_BDTR_BKE,
+ bdtr);
+
+ return 0;
+}
+
+static int stm32_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
+ enum pwm_polarity polarity)
+{
+ u32 mask;
+ struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
+
+ mask = TIM_CCER_CC1P << (pwm->hwpwm * 4);
+ if (priv->have_complementary_output)
+ mask |= TIM_CCER_CC1NP << (pwm->hwpwm * 4);
+
+ regmap_update_bits(priv->regmap, TIM_CCER, mask,
+ polarity == PWM_POLARITY_NORMAL ? 0 : mask);
+
+ return 0;
+}
+
+static int stm32_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ u32 mask;
+ struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
+
+ clk_enable(priv->clk);
+
+ /* Enable channel */
+ mask = TIM_CCER_CC1E << (pwm->hwpwm * 4);
+ if (priv->have_complementary_output)
+ mask |= TIM_CCER_CC1NE << (pwm->hwpwm * 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 pwm_chip *chip, struct pwm_device *pwm)
+{
+ u32 mask;
+ struct stm32_pwm *priv = to_stm32_pwm_dev(chip);
+
+ /* Disable channel */
+ mask = TIM_CCER_CC1E << (pwm->hwpwm * 4);
+ if (priv->have_complementary_output)
+ mask |= TIM_CCER_CC1NE << (pwm->hwpwm * 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;
+ int ret;
+
+ pwm_get_state(pwm, &curstate);
+ enabled = curstate.enabled;
+
+ if (enabled && !state->enabled) {
+ stm32_pwm_disable(chip, pwm);
+ return 0;
+ }
+
+ if (state->polarity != curstate.polarity && enabled)
+ stm32_pwm_set_polarity(chip, pwm, state->polarity);
+
+ ret = stm32_pwm_config(chip, pwm, state->duty_cycle, state->period);
+ if (ret)
+ return ret;
+
+ if (!enabled && state->enabled)
+ ret = stm32_pwm_enable(chip, pwm);
+
+ return ret;
+}
+
+static const struct pwm_ops stm32pwm_ops = {
+ .owner = THIS_MODULE,
+ .apply = stm32_pwm_apply,
+};
+
+static bool stm32_pwm_detect_breakinput(struct regmap *regmap)
+{
+ u32 bdtr;
+
+ /*
+ * If breakinput enable bit doesn't exist writing 1 will have no
+ * effect so we can detect it.
+ */
+ regmap_update_bits(regmap, TIM_BDTR, TIM_BDTR_BKE, TIM_BDTR_BKE);
+ regmap_read(regmap, TIM_BDTR, &bdtr);
+ regmap_update_bits(regmap, TIM_BDTR, TIM_BDTR_BKE, 0);
+
+ return (bdtr != 0);
+}
+
+static bool stm32_pwm_detect_complementary(struct regmap *regmap)
+{
+ u32 ccer;
+
+ /*
+ * If complementary bit doesn't exist writing 1 will have no
+ * effect so we can detect it.
+ */
+ regmap_update_bits(regmap, TIM_CCER, TIM_CCER_CC1NE, TIM_CCER_CC1NE);
+ regmap_read(regmap, TIM_CCER, &ccer);
+ regmap_update_bits(regmap, TIM_CCER, TIM_CCER_CCXE, 0);
+
+ return (ccer != 0);
+}
+
+static int stm32_pwm_detect_channels(struct regmap *regmap)
+{
+ int channels = 0;
+ u32 ccer;
+
+ /*
+ * If channels enable bits don't exist writing 1 will have no
+ * effect so we can detect and count them.
+ */
+ regmap_update_bits(regmap, TIM_CCER, TIM_CCER_CCXE, TIM_CCER_CCXE);
+ regmap_read(regmap, TIM_CCER, &ccer);
+ regmap_update_bits(regmap, TIM_CCER, TIM_CCER_CCXE, 0);
+
+ if (ccer & TIM_CCER_CC1E)
+ channels++;
+
+ if (ccer & TIM_CCER_CC2E)
+ channels++;
+
+ if (ccer & TIM_CCER_CC3E)
+ channels++;
+
+ if (ccer & TIM_CCER_CC4E)
+ channels++;
+
+ return channels;
+}
+
+static int stm32_pwm_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+ struct stm32_gptimer *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;
+
+ priv->have_breakinput = stm32_pwm_detect_breakinput(priv->regmap);
+ priv->have_complementary_output =
+ stm32_pwm_detect_complementary(priv->regmap);
+ priv->npwm = stm32_pwm_detect_channels(priv->regmap);
+
+ if (!of_property_read_u32(np, "st,breakinput-polarity",
+ &priv->breakinput_polarity))
+ priv->use_breakinput = true;
+
+ priv->chip.base = -1;
+ priv->chip.dev = dev;
+ priv->chip.ops = &stm32pwm_ops;
+ priv->chip.npwm = priv->npwm;
+
+ 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->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", }
+};
+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");
--
1.9.1
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