[RFC v4 2/4] pwm: starfive: Add PWM driver support

From: William Qiu
Date: Fri Aug 25 2023 - 04:14:40 EST

Add Pulse Width Modulation driver support for StarFive
JH7100 and JH7110 SoC.

Co-developed-by: Hal Feng <hal.feng@xxxxxxxxxxxxxxxx>
Signed-off-by: Hal Feng <hal.feng@xxxxxxxxxxxxxxxx>
Signed-off-by: William Qiu <william.qiu@xxxxxxxxxxxxxxxx>
---
MAINTAINERS | 7 ++
drivers/pwm/Kconfig | 9 ++
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-starfive-ptc.c | 192 +++++++++++++++++++++++++++++++++
4 files changed, 209 insertions(+)
create mode 100644 drivers/pwm/pwm-starfive-ptc.c

diff --git a/MAINTAINERS b/MAINTAINERS
index d590ce31aa72..0e47818c6f64 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -20299,6 +20299,13 @@ F: drivers/pinctrl/starfive/pinctrl-starfive-jh71*
F: include/dt-bindings/pinctrl/pinctrl-starfive-jh7100.h
F: include/dt-bindings/pinctrl/starfive,jh7110-pinctrl.h

+STARFIVE JH71X0 PWM DRIVERS
+M: William Qiu <william.qiu@xxxxxxxxxxxxxxxx>
+M: Hal Feng <hal.feng@xxxxxxxxxxxxxxxx>
+S: Supported
+F: Documentation/devicetree/bindings/pwm/starfive,jh7100-pwm.yaml
+F: drivers/pwm/pwm-starfive-ptc.c
+
STARFIVE JH71X0 RESET CONTROLLER DRIVERS
M: Emil Renner Berthing <kernel@xxxxxxxx>
M: Hal Feng <hal.feng@xxxxxxxxxxxxxxxx>
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 6210babb0741..48800f33b5c1 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -569,6 +569,15 @@ config PWM_SPRD
To compile this driver as a module, choose M here: the module
will be called pwm-sprd.

+config PWM_STARFIVE_PTC
+ tristate "StarFive PWM PTC support"
+ depends on ARCH_STARFIVE || COMPILE_TEST
+ help
+ Generic PWM framework driver for StarFive SoCs.
+
+ To compile this driver as a module, choose M here: the module
+ will be called pwm-starfive-ptc.
+
config PWM_STI
tristate "STiH4xx PWM support"
depends on ARCH_STI || COMPILE_TEST
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index c822389c2a24..d2b2a3aeea22 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -52,6 +52,7 @@ obj-$(CONFIG_PWM_SIFIVE) += pwm-sifive.o
obj-$(CONFIG_PWM_SL28CPLD) += pwm-sl28cpld.o
obj-$(CONFIG_PWM_SPEAR) += pwm-spear.o
obj-$(CONFIG_PWM_SPRD) += pwm-sprd.o
+obj-$(CONFIG_PWM_STARFIVE_PTC) += pwm-starfive-ptc.o
obj-$(CONFIG_PWM_STI) += pwm-sti.o
obj-$(CONFIG_PWM_STM32) += pwm-stm32.o
obj-$(CONFIG_PWM_STM32_LP) += pwm-stm32-lp.o
diff --git a/drivers/pwm/pwm-starfive-ptc.c b/drivers/pwm/pwm-starfive-ptc.c
new file mode 100644
index 000000000000..57b5736f6732
--- /dev/null
+++ b/drivers/pwm/pwm-starfive-ptc.c
@@ -0,0 +1,192 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PWM driver for the StarFive JH71x0 SoC
+ *
+ * Copyright (C) 2018-2023 StarFive Technology Co., Ltd.
+ */
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+
+/* Access PTC register (CNTR, HRC, LRC and CTRL) */
+#define REG_PTC_BASE_ADDR_SUB(base, N) \
+((base) + (((N) > 3) ? (((N) % 4) * 0x10 + (1 << 15)) : ((N) * 0x10)))
+#define REG_PTC_RPTC_CNTR(base, N) (REG_PTC_BASE_ADDR_SUB(base, N))
+#define REG_PTC_RPTC_HRC(base, N) (REG_PTC_BASE_ADDR_SUB(base, N) + 0x4)
+#define REG_PTC_RPTC_LRC(base, N) (REG_PTC_BASE_ADDR_SUB(base, N) + 0x8)
+#define REG_PTC_RPTC_CTRL(base, N) (REG_PTC_BASE_ADDR_SUB(base, N) + 0xC)
+
+/* PTC_RPTC_CTRL register bits*/
+#define PTC_EN BIT(0)
+#define PTC_ECLK BIT(1)
+#define PTC_NEC BIT(2)
+#define PTC_OE BIT(3)
+#define PTC_SIGNLE BIT(4)
+#define PTC_INTE BIT(5)
+#define PTC_INT BIT(6)
+#define PTC_CNTRRST BIT(7)
+#define PTC_CAPTE BIT(8)
+
+struct starfive_pwm_ptc_device {
+ struct pwm_chip chip;
+ struct clk *clk;
+ struct reset_control *rst;
+ void __iomem *regs;
+ u32 clk_rate; /* PWM APB clock frequency */
+};
+
+static inline
+struct starfive_pwm_ptc_device *chip_to_starfive_ptc(struct pwm_chip *c)
+{
+ return container_of(c, struct starfive_pwm_ptc_device, chip);
+}
+
+static int starfive_pwm_ptc_get_state(struct pwm_chip *chip,
+ struct pwm_device *dev,
+ struct pwm_state *state)
+{
+ struct starfive_pwm_ptc_device *pwm = chip_to_starfive_ptc(chip);
+ u32 period_data, duty_data, ctrl_data;
+
+ period_data = readl(REG_PTC_RPTC_LRC(pwm->regs, dev->hwpwm));
+ duty_data = readl(REG_PTC_RPTC_HRC(pwm->regs, dev->hwpwm));
+ ctrl_data = readl(REG_PTC_RPTC_CTRL(pwm->regs, dev->hwpwm));
+
+ state->period = DIV_ROUND_CLOSEST_ULL((u64)period_data * NSEC_PER_SEC, pwm->clk_rate);
+ state->duty_cycle = DIV_ROUND_CLOSEST_ULL((u64)duty_data * NSEC_PER_SEC, pwm->clk_rate);
+ state->polarity = PWM_POLARITY_INVERSED;
+ state->enabled = (ctrl_data & PTC_EN) ? true : false;
+
+ return 0;
+}
+
+static int starfive_pwm_ptc_apply(struct pwm_chip *chip,
+ struct pwm_device *dev,
+ const struct pwm_state *state)
+{
+ struct starfive_pwm_ptc_device *pwm = chip_to_starfive_ptc(chip);
+ u32 period_data, duty_data, ctrl_data = 0;
+
+ if (state->polarity != PWM_POLARITY_INVERSED)
+ return -EINVAL;
+
+ period_data = DIV_ROUND_CLOSEST_ULL(state->period * pwm->clk_rate,
+ NSEC_PER_SEC);
+ duty_data = DIV_ROUND_CLOSEST_ULL(state->duty_cycle * pwm->clk_rate,
+ NSEC_PER_SEC);
+
+ writel(period_data, REG_PTC_RPTC_LRC(pwm->regs, dev->hwpwm));
+ writel(duty_data, REG_PTC_RPTC_HRC(pwm->regs, dev->hwpwm));
+ writel(0, REG_PTC_RPTC_CNTR(pwm->regs, dev->hwpwm));
+
+ ctrl_data = readl(REG_PTC_RPTC_CTRL(pwm->regs, dev->hwpwm));
+ if (state->enabled)
+ writel(ctrl_data | PTC_EN | PTC_OE, REG_PTC_RPTC_CTRL(pwm->regs, dev->hwpwm));
+ else
+ writel(ctrl_data & ~(PTC_EN | PTC_OE), REG_PTC_RPTC_CTRL(pwm->regs, dev->hwpwm));
+
+ return 0;
+}
+
+static const struct pwm_ops starfive_pwm_ptc_ops = {
+ .get_state = starfive_pwm_ptc_get_state,
+ .apply = starfive_pwm_ptc_apply,
+ .owner = THIS_MODULE,
+};
+
+static int starfive_pwm_ptc_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct starfive_pwm_ptc_device *pwm;
+ struct pwm_chip *chip;
+ int ret;
+
+ pwm = devm_kzalloc(dev, sizeof(*pwm), GFP_KERNEL);
+ if (!pwm)
+ return -ENOMEM;
+
+ chip = &pwm->chip;
+ chip->dev = dev;
+ chip->ops = &starfive_pwm_ptc_ops;
+ chip->npwm = 8;
+ chip->of_pwm_n_cells = 3;
+
+ pwm->regs = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(pwm->regs))
+ return dev_err_probe(dev, PTR_ERR(pwm->regs),
+ "Unable to map IO resources\n");
+
+ pwm->clk = devm_clk_get(dev, NULL);
+ if (IS_ERR(pwm->clk))
+ return dev_err_probe(dev, PTR_ERR(pwm->clk),
+ "Unable to get pwm's clock\n");
+
+ pwm->rst = devm_reset_control_get_exclusive(dev, NULL);
+ if (IS_ERR(pwm->rst))
+ return dev_err_probe(dev, PTR_ERR(pwm->rst),
+ "Unable to get pwm's reset\n");
+
+ ret = clk_prepare_enable(pwm->clk);
+ if (ret) {
+ dev_err(dev,
+ "Failed to enable clock for pwm: %d\n", ret);
+ return ret;
+ }
+
+ reset_control_deassert(pwm->rst);
+
+ pwm->clk_rate = clk_get_rate(pwm->clk);
+ if (pwm->clk_rate <= 0) {
+ dev_warn(dev, "Failed to get APB clock rate\n");
+ return -EINVAL;
+ }
+
+ ret = devm_pwmchip_add(dev, chip);
+ if (ret < 0) {
+ dev_err(dev, "Cannot register PTC: %d\n", ret);
+ clk_disable_unprepare(pwm->clk);
+ reset_control_assert(pwm->rst);
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, pwm);
+
+ return 0;
+}
+
+static int starfive_pwm_ptc_remove(struct platform_device *dev)
+{
+ struct starfive_pwm_ptc_device *pwm = platform_get_drvdata(dev);
+
+ reset_control_assert(pwm->rst);
+ clk_disable_unprepare(pwm->clk);
+
+ return 0;
+}
+
+static const struct of_device_id starfive_pwm_ptc_of_match[] = {
+ { .compatible = "starfive,jh7100-pwm" },
+ { .compatible = "starfive,jh7110-pwm" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, starfive_pwm_ptc_of_match);
+
+static struct platform_driver starfive_pwm_ptc_driver = {
+ .probe = starfive_pwm_ptc_probe,
+ .remove = starfive_pwm_ptc_remove,
+ .driver = {
+ .name = "pwm-starfive-ptc",
+ .of_match_table = starfive_pwm_ptc_of_match,
+ },
+};
+module_platform_driver(starfive_pwm_ptc_driver);
+
+MODULE_AUTHOR("Jieqin Chen");
+MODULE_AUTHOR("Hal Feng <hal.feng@xxxxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("StarFive PWM PTC driver");
+MODULE_LICENSE("GPL");
--
2.34.1