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Date: Fri, 2 Dec 2016 11:17:19 +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 v3 4/7] PWM: add pwm driver for stm32 plaftorm
This driver add 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, counter register size...
Use DT parameters to handle those differentes configuration
version 2:
- only keep one comptatible
- use DT paramaters to discover hardware block configuration
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@...com>
---
drivers/pwm/Kconfig | 8 ++
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-stm32.c | 285 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 294 insertions(+)
create mode 100644 drivers/pwm/pwm-stm32.c
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index bf01288..a89fdba 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -388,6 +388,14 @@ 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
+ depends on OF
+ select MFD_STM32_GP_TIMER
+ help
+ Generic PWM framework driver for STM32 SoCs.
+
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..a362f63
--- /dev/null
+++ b/drivers/pwm/pwm-stm32.c
@@ -0,0 +1,285 @@
+/*
+ * 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/of.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+
+#include <linux/mfd/stm32-gptimer.h>
+
+#define DRIVER_NAME "stm32-pwm"
+
+#define CAP_COMPLEMENTARY BIT(0)
+#define CAP_32BITS_COUNTER BIT(1)
+#define CAP_BREAKINPUT BIT(2)
+#define CAP_BREAKINPUT_POLARITY BIT(3)
+
+struct stm32_pwm_dev {
+ struct device *dev;
+ struct clk *clk;
+ struct regmap *regmap;
+ struct pwm_chip chip;
+ int caps;
+ int npwm;
+ u32 polarity;
+};
+
+#define to_stm32_pwm_dev(x) container_of(chip, struct stm32_pwm_dev, chip)
+
+static u32 __active_channels(struct stm32_pwm_dev *pwm_dev)
+{
+ u32 ccer;
+
+ regmap_read(pwm_dev->regmap, TIM_CCER, &ccer);
+
+ return ccer & TIM_CCER_CCXE;
+}
+
+static int write_ccrx(struct stm32_pwm_dev *dev, struct pwm_device *pwm,
+ u32 ccr)
+{
+ switch (pwm->hwpwm) {
+ case 0:
+ return regmap_write(dev->regmap, TIM_CCR1, ccr);
+ case 1:
+ return regmap_write(dev->regmap, TIM_CCR2, ccr);
+ case 2:
+ return regmap_write(dev->regmap, TIM_CCR3, ccr);
+ case 3:
+ return regmap_write(dev->regmap, TIM_CCR4, ccr);
+ }
+ return -EINVAL;
+}
+
+static int stm32_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+ int duty_ns, int period_ns)
+{
+ struct stm32_pwm_dev *dev = to_stm32_pwm_dev(chip);
+ unsigned long long prd, div, dty;
+ int prescaler = 0;
+ u32 max_arr = 0xFFFF, ccmr, mask, shift, bdtr;
+
+ if (dev->caps & CAP_32BITS_COUNTER)
+ max_arr = 0xFFFFFFFF;
+
+ /* Period and prescaler values depends of clock rate */
+ div = (unsigned long long)clk_get_rate(dev->clk) * period_ns;
+
+ do_div(div, NSEC_PER_SEC);
+ prd = div;
+
+ while (div > 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(dev) & ~(1 << pwm->hwpwm * 4)) {
+ u32 psc, arr;
+
+ regmap_read(dev->regmap, TIM_PSC, &psc);
+ regmap_read(dev->regmap, TIM_ARR, &arr);
+
+ if ((psc != prescaler) || (arr != prd - 1))
+ return -EINVAL;
+ }
+
+ regmap_write(dev->regmap, TIM_PSC, prescaler);
+ regmap_write(dev->regmap, TIM_ARR, prd - 1);
+ regmap_update_bits(dev->regmap, TIM_CR1, TIM_CR1_ARPE, TIM_CR1_ARPE);
+
+ /* Calculate the duty cycles */
+ dty = prd * duty_ns;
+ do_div(dty, period_ns);
+
+ write_ccrx(dev, pwm, dty);
+
+ /* Configure output mode */
+ shift = (pwm->hwpwm & 0x1) * 8;
+ ccmr = (TIM_CCMR_PE | TIM_CCMR_M1) << shift;
+ mask = 0xFF << shift;
+
+ if (pwm->hwpwm & 0x2)
+ regmap_update_bits(dev->regmap, TIM_CCMR2, mask, ccmr);
+ else
+ regmap_update_bits(dev->regmap, TIM_CCMR1, mask, ccmr);
+
+ if (!(dev->caps & CAP_BREAKINPUT))
+ return 0;
+
+ bdtr = TIM_BDTR_MOE | TIM_BDTR_AOE;
+
+ if (dev->caps & CAP_BREAKINPUT_POLARITY)
+ bdtr |= TIM_BDTR_BKE;
+
+ if (dev->polarity)
+ bdtr |= TIM_BDTR_BKP;
+
+ regmap_update_bits(dev->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_dev *dev = to_stm32_pwm_dev(chip);
+
+ mask = TIM_CCER_CC1P << (pwm->hwpwm * 4);
+ if (dev->caps & CAP_COMPLEMENTARY)
+ mask |= TIM_CCER_CC1NP << (pwm->hwpwm * 4);
+
+ regmap_update_bits(dev->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_dev *dev = to_stm32_pwm_dev(chip);
+
+ clk_enable(dev->clk);
+
+ /* Enable channel */
+ mask = TIM_CCER_CC1E << (pwm->hwpwm * 4);
+ if (dev->caps & CAP_COMPLEMENTARY)
+ mask |= TIM_CCER_CC1NE << (pwm->hwpwm * 4);
+
+ regmap_update_bits(dev->regmap, TIM_CCER, mask, mask);
+
+ /* Make sure that registers are updated */
+ regmap_update_bits(dev->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG);
+
+ /* Enable controller */
+ regmap_update_bits(dev->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_dev *dev = to_stm32_pwm_dev(chip);
+
+ /* Disable channel */
+ mask = TIM_CCER_CC1E << (pwm->hwpwm * 4);
+ if (dev->caps & CAP_COMPLEMENTARY)
+ mask |= TIM_CCER_CC1NE << (pwm->hwpwm * 4);
+
+ regmap_update_bits(dev->regmap, TIM_CCER, mask, 0);
+
+ /* When all channels are disabled, we can disable the controller */
+ if (!__active_channels(dev))
+ regmap_update_bits(dev->regmap, TIM_CR1, TIM_CR1_CEN, 0);
+
+ clk_disable(dev->clk);
+}
+
+static const struct pwm_ops stm32pwm_ops = {
+ .config = stm32_pwm_config,
+ .set_polarity = stm32_pwm_set_polarity,
+ .enable = stm32_pwm_enable,
+ .disable = stm32_pwm_disable,
+};
+
+static int stm32_pwm_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+ struct stm32_gptimer_dev *mfd = dev_get_drvdata(pdev->dev.parent);
+ struct stm32_pwm_dev *pwm;
+ int ret;
+
+ pwm = devm_kzalloc(dev, sizeof(*pwm), GFP_KERNEL);
+ if (!pwm)
+ return -ENOMEM;
+
+ pwm->regmap = mfd->regmap;
+ pwm->clk = mfd->clk;
+
+ if (!pwm->regmap || !pwm->clk)
+ return -EINVAL;
+
+ if (of_property_read_bool(np, "st,complementary"))
+ pwm->caps |= CAP_COMPLEMENTARY;
+
+ if (of_property_read_bool(np, "st,32bits-counter"))
+ pwm->caps |= CAP_32BITS_COUNTER;
+
+ if (of_property_read_bool(np, "st,breakinput"))
+ pwm->caps |= CAP_BREAKINPUT;
+
+ if (!of_property_read_u32(np, "st,breakinput-polarity", &pwm->polarity))
+ pwm->caps |= CAP_BREAKINPUT_POLARITY;
+
+ of_property_read_u32(np, "st,pwm-num-chan", &pwm->npwm);
+
+ pwm->chip.base = -1;
+ pwm->chip.dev = dev;
+ pwm->chip.ops = &stm32pwm_ops;
+ pwm->chip.npwm = pwm->npwm;
+
+ ret = pwmchip_add(&pwm->chip);
+ if (ret < 0)
+ return ret;
+
+ platform_set_drvdata(pdev, pwm);
+
+ return 0;
+}
+
+static int stm32_pwm_remove(struct platform_device *pdev)
+{
+ struct stm32_pwm_dev *pwm = platform_get_drvdata(pdev);
+ int i;
+
+ for (i = 0; i < pwm->npwm; i++)
+ pwm_disable(&pwm->chip.pwms[i]);
+
+ pwmchip_remove(&pwm->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 = DRIVER_NAME,
+ .of_match_table = stm32_pwm_of_match,
+ },
+};
+module_platform_driver(stm32_pwm_driver);
+
+MODULE_ALIAS("platform:" DRIVER_NAME);
+MODULE_DESCRIPTION("STMicroelectronics STM32 PWM driver");
+MODULE_LICENSE("GPL");
--
1.9.1
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