From a53d3c9d614d74d1664288855390810d868bddc4 Mon Sep 17 00:00:00 2001 From: Drew Fustini Date: Wed, 25 Oct 2023 17:24:46 -0500 Subject: [PATCH] pwm: Add driver for AXI PWM generator Add support for the Analog Devices AXI PWM Generator. This device is an FPGA-implemented peripheral used as PWM signal generator and can be interfaced with AXI4. The register map of this peripheral makes it possible to configure the period and duty cycle of the output signal. Link: https://wiki.analog.com/resources/fpga/docs/axi_pwm_gen Co-developed-by: Sergiu Cuciurean Signed-off-by: Sergiu Cuciurean Co-developed-by: David Lechner Signed-off-by: David Lechner Signed-off-by: Drew Fustini --- MAINTAINERS | 1 + drivers/pwm/Kconfig | 12 +++ drivers/pwm/Makefile | 1 + drivers/pwm/pwm-axi-pwmgen.c | 201 +++++++++++++++++++++++++++++++++++ 4 files changed, 215 insertions(+) create mode 100644 drivers/pwm/pwm-axi-pwmgen.c diff --git a/MAINTAINERS b/MAINTAINERS index b0296f822ac6dc..e4e9365ef3e324 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -3422,6 +3422,7 @@ L: linux-pwm@vger.kernel.org S: Supported W: https://ez.analog.com/linux-software-drivers F: Documentation/devicetree/bindings/pwm/adi,axi-pwmgen.yaml +F: drivers/pwm/pwm-axi-pwmgen.c AXI SPI ENGINE M: Michael Hennerich diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index 4b956d661755d6..4caa4d8aa3ef1f 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -98,6 +98,18 @@ config PWM_ATMEL_TCB To compile this driver as a module, choose M here: the module will be called pwm-atmel-tcb. +config PWM_AXI_PWMGEN + tristate "Analog Devices AXI PWM generator" + depends on HAS_IOMEM + help + This enables support for the Analog Devices AXI PWM generator. + + This is a single output configurable PWM generator with variable + pulse width and period. + + To compile this driver as a module, choose M here: the module will be + called pwm-axi-pwmgen. + config PWM_BCM_IPROC tristate "iProc PWM support" depends on ARCH_BCM_IPROC || COMPILE_TEST diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index c5ec9e168ee7c5..8322089954e997 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -6,6 +6,7 @@ obj-$(CONFIG_PWM_APPLE) += pwm-apple.o obj-$(CONFIG_PWM_ATMEL) += pwm-atmel.o obj-$(CONFIG_PWM_ATMEL_HLCDC_PWM) += pwm-atmel-hlcdc.o obj-$(CONFIG_PWM_ATMEL_TCB) += pwm-atmel-tcb.o +obj-$(CONFIG_PWM_AXI_PWMGEN) += pwm-axi-pwmgen.o obj-$(CONFIG_PWM_BCM_IPROC) += pwm-bcm-iproc.o obj-$(CONFIG_PWM_BCM_KONA) += pwm-bcm-kona.o obj-$(CONFIG_PWM_BCM2835) += pwm-bcm2835.o diff --git a/drivers/pwm/pwm-axi-pwmgen.c b/drivers/pwm/pwm-axi-pwmgen.c new file mode 100644 index 00000000000000..df05f469c430c8 --- /dev/null +++ b/drivers/pwm/pwm-axi-pwmgen.c @@ -0,0 +1,201 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Analog Devices AXI PWM generator + * + * Copyright 2023 Analog Devices Inc. + */ +#include +#include +#include +#include +#include +#include +#include +#include + +#define AXI_PWMGEN_NPWM 4 +#define AXI_PWMGEN_REG_CORE_VERSION 0x00 +#define AXI_PWMGEN_REG_ID 0x04 +#define AXI_PWMGEN_REG_SCRATCHPAD 0x08 +#define AXI_PWMGEN_REG_CORE_MAGIC 0x0C +#define AXI_PWMGEN_REG_CONFIG 0x10 +#define AXI_PWMGEN_REG_NPWM 0x14 +#define AXI_PWMGEN_CH_PERIOD_BASE 0x40 +#define AXI_PWMGEN_CH_DUTY_BASE 0x44 +#define AXI_PWMGEN_CH_OFFSET_BASE 0x48 +#define AXI_PWMGEN_CHX_PERIOD(ch) (AXI_PWMGEN_CH_PERIOD_BASE + (12 * (ch))) +#define AXI_PWMGEN_CHX_DUTY(ch) (AXI_PWMGEN_CH_DUTY_BASE + (12 * (ch))) +#define AXI_PWMGEN_CHX_OFFSET(ch) (AXI_PWMGEN_CH_OFFSET_BASE + (12 * (ch))) +#define AXI_PWMGEN_TEST_DATA 0x5A0F0081 +#define AXI_PWMGEN_LOAD_CONIG BIT(1) +#define AXI_PWMGEN_RESET BIT(0) + +struct axi_pwmgen { + struct pwm_chip chip; + struct clk *clk; + void __iomem *base; + + /* Used to store the period when the channel is disabled */ + unsigned int ch_period[AXI_PWMGEN_NPWM]; + bool ch_enabled[AXI_PWMGEN_NPWM]; +}; + +static inline unsigned int axi_pwmgen_read(struct axi_pwmgen *pwm, + unsigned int reg) +{ + return readl(pwm->base + reg); +} + +static inline void axi_pwmgen_write(struct axi_pwmgen *pwm, + unsigned int reg, + unsigned int value) +{ + writel(value, pwm->base + reg); +} + +static void axi_pwmgen_write_mask(struct axi_pwmgen *pwm, + unsigned int reg, + unsigned int mask, + unsigned int value) +{ + unsigned int temp; + + temp = axi_pwmgen_read(pwm, reg); + axi_pwmgen_write(pwm, reg, (temp & ~mask) | value); +} + +static struct axi_pwmgen *to_axi_pwmgen(struct pwm_chip *chip) +{ + return container_of(chip, struct axi_pwmgen, chip); +} + +static int axi_pwmgen_apply(struct pwm_chip *chip, struct pwm_device *device, + const struct pwm_state *state) +{ + struct axi_pwmgen *pwm = to_axi_pwmgen(chip); + unsigned long clk_rate = clk_get_rate(pwm->clk); + unsigned int ch = device->hwpwm; + u64 period_cnt, duty_cnt; + + period_cnt = DIV_ROUND_UP_ULL(state->period * clk_rate, NSEC_PER_SEC); + if (period_cnt > UINT_MAX) + return -EINVAL; + + pwm->ch_period[ch] = period_cnt; + pwm->ch_enabled[ch] = state->enabled; + axi_pwmgen_write(pwm, AXI_PWMGEN_CHX_PERIOD(ch), + state->enabled ? period_cnt : 0); + + duty_cnt = DIV_ROUND_UP_ULL(state->duty_cycle * clk_rate, NSEC_PER_SEC); + axi_pwmgen_write(pwm, AXI_PWMGEN_CHX_DUTY(ch), duty_cnt); + + axi_pwmgen_write(pwm, AXI_PWMGEN_REG_CONFIG, AXI_PWMGEN_LOAD_CONIG); + + return 0; +} + +static int axi_pwmgen_get_state(struct pwm_chip *chip, struct pwm_device *pwm, + struct pwm_state *state) +{ + struct axi_pwmgen *pwmgen = to_axi_pwmgen(chip); + unsigned long rate = clk_get_rate(pwmgen->clk); + size_t ch = pwm->hwpwm; + unsigned int cnt; + + state->enabled = pwmgen->ch_enabled[ch]; + + if (state->enabled) + cnt = axi_pwmgen_read(pwmgen, AXI_PWMGEN_CHX_PERIOD(ch)); + else + cnt = pwmgen->ch_period[ch]; + + state->period = DIV_ROUND_CLOSEST_ULL((u64)cnt * NSEC_PER_SEC, rate); + + cnt = axi_pwmgen_read(pwmgen, AXI_PWMGEN_CHX_DUTY(ch)); + state->duty_cycle = DIV_ROUND_CLOSEST_ULL((u64)cnt * NSEC_PER_SEC, rate); + + return 0; +} + +static const struct pwm_ops axi_pwmgen_pwm_ops = { + .apply = axi_pwmgen_apply, + .get_state = axi_pwmgen_get_state, +}; + +static int axi_pwmgen_setup(struct pwm_chip *chip) +{ + struct axi_pwmgen *pwm; + unsigned int reg; + int idx; + + pwm = to_axi_pwmgen(chip); + axi_pwmgen_write(pwm, AXI_PWMGEN_REG_SCRATCHPAD, AXI_PWMGEN_TEST_DATA); + reg = axi_pwmgen_read(pwm, AXI_PWMGEN_REG_SCRATCHPAD); + if (reg != AXI_PWMGEN_TEST_DATA) + return dev_err_probe(chip->dev, -EIO, + "failed to access the device registers\n"); + + pwm->chip.npwm = axi_pwmgen_read(pwm, AXI_PWMGEN_REG_NPWM); + if (pwm->chip.npwm > AXI_PWMGEN_NPWM) + return -EINVAL; + + /* Disable all the outputs */ + for (idx = 0; idx < pwm->chip.npwm; idx++) { + axi_pwmgen_write(pwm, AXI_PWMGEN_CHX_PERIOD(idx), 0); + axi_pwmgen_write(pwm, AXI_PWMGEN_CHX_DUTY(idx), 0); + axi_pwmgen_write(pwm, AXI_PWMGEN_CHX_OFFSET(idx), 0); + } + + /* Enable the core */ + axi_pwmgen_write_mask(pwm, AXI_PWMGEN_REG_CONFIG, AXI_PWMGEN_RESET, 0); + + return 0; +} + +static int axi_pwmgen_probe(struct platform_device *pdev) +{ + struct axi_pwmgen *pwm; + int ret; + + pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL); + if (!pwm) + return -ENOMEM; + + pwm->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(pwm->base)) + return PTR_ERR(pwm->base); + + pwm->clk = devm_clk_get_enabled(&pdev->dev, NULL); + if (IS_ERR(pwm->clk)) + return PTR_ERR(pwm->clk); + + pwm->chip.dev = &pdev->dev; + pwm->chip.ops = &axi_pwmgen_pwm_ops; + pwm->chip.base = -1; + + ret = axi_pwmgen_setup(&pwm->chip); + if (ret < 0) + return ret; + + return devm_pwmchip_add(&pdev->dev, &pwm->chip); +} + +static const struct of_device_id axi_pwmgen_ids[] = { + { .compatible = "adi,axi-pwmgen" }, + { } +}; +MODULE_DEVICE_TABLE(of, axi_pwmgen_ids); + +static struct platform_driver axi_pwmgen_driver = { + .driver = { + .name = "axi-pwmgen", + .of_match_table = axi_pwmgen_ids, + }, + .probe = axi_pwmgen_probe, +}; + +module_platform_driver(axi_pwmgen_driver); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Sergiu Cuciurean "); +MODULE_DESCRIPTION("Driver for the Analog Devices AXI PWM generator");