This adds PWM support for Xilinx LogiCORE IP AXI soft timers commonly found on Xilinx FPGAs. There is another driver for this device located at arch/microblaze/kernel/timer.c, but it is only used for timekeeping. This driver was written with reference to Xilinx DS764 for v1.03.a [1]. [1] https://www.xilinx.com/support/documentation/ip_documentation/axi_timer/v1_03_a/axi_timer_ds764.pdf Signed-off-by: Sean Anderson <sean.anderson@xxxxxxxx> --- arch/arm64/configs/defconfig | 1 + drivers/pwm/Kconfig | 11 ++ drivers/pwm/Makefile | 1 + drivers/pwm/pwm-xilinx.c | 322 +++++++++++++++++++++++++++++++++++ 4 files changed, 335 insertions(+) create mode 100644 drivers/pwm/pwm-xilinx.c diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig index 08c6f769df9a..81794209f287 100644 --- a/arch/arm64/configs/defconfig +++ b/arch/arm64/configs/defconfig @@ -1083,6 +1083,7 @@ CONFIG_PWM_SAMSUNG=y CONFIG_PWM_SL28CPLD=m CONFIG_PWM_SUN4I=m CONFIG_PWM_TEGRA=m +CONFIG_PWM_XILINX=m CONFIG_SL28CPLD_INTC=y CONFIG_QCOM_PDC=y CONFIG_RESET_IMX7=y diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index d3371ac7b871..01e62928f4bf 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -628,4 +628,15 @@ config PWM_VT8500 To compile this driver as a module, choose M here: the module will be called pwm-vt8500. +config PWM_XILINX + tristate "Xilinx AXI Timer PWM support" + depends on !MICROBLAZE + help + PWM framework driver for Xilinx LogiCORE IP AXI Timers. This + timer is typically a soft core which may be present in Xilinx + FPGAs. If you don't have this IP in your design, choose N. + + To compile this driver as a module, choose M here: the module + will be called pwm-xilinx. + endif diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index d3879619bd76..fc1bd6ccc9ed 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -59,3 +59,4 @@ obj-$(CONFIG_PWM_TIEHRPWM) += pwm-tiehrpwm.o obj-$(CONFIG_PWM_TWL) += pwm-twl.o obj-$(CONFIG_PWM_TWL_LED) += pwm-twl-led.o obj-$(CONFIG_PWM_VT8500) += pwm-vt8500.o +obj-$(CONFIG_PWM_XILINX) += pwm-xilinx.o diff --git a/drivers/pwm/pwm-xilinx.c b/drivers/pwm/pwm-xilinx.c new file mode 100644 index 000000000000..240bd2993f97 --- /dev/null +++ b/drivers/pwm/pwm-xilinx.c @@ -0,0 +1,322 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (C) 2021 Sean Anderson <sean.anderson@xxxxxxxx> + */ +#include <asm/io.h> +#include <linux/clk.h> +#include <linux/device.h> +#include <linux/debugfs.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/pwm.h> + +#define TCSR0 0x00 +#define TLR0 0x04 +#define TCR0 0x08 +#define TCSR1 0x10 +#define TLR1 0x14 +#define TCR1 0x18 + +#define TCSR_MDT BIT(0) +#define TCSR_UDT BIT(1) +#define TCSR_GENT BIT(2) +#define TCSR_CAPT BIT(3) +#define TCSR_ARHT BIT(4) +#define TCSR_LOAD BIT(5) +#define TCSR_ENIT BIT(6) +#define TCSR_ENT BIT(7) +#define TCSR_TINT BIT(8) +#define TCSR_PWMA BIT(9) +#define TCSR_ENALL BIT(10) +#define TCSR_CASC BIT(11) + +/* Bits we need to set/clear to enable PWM mode, not including CASC */ +#define TCSR_SET (TCSR_GENT | TCSR_ARHT | TCSR_ENT | TCSR_PWMA) +#define TCSR_CLEAR (TCSR_MDT | TCSR_LOAD) + +#define NSEC_PER_SEC_ULL 1000000000ULL + +/** + * struct xilinx_pwm_device - Driver data for Xilinx AXI timer PWM driver + * @chip: PWM controller chip + * @clk: Parent clock + * @regs: Base address of this device + * @width: Width of the counters, in bits + */ +struct xilinx_pwm_device { + struct pwm_chip chip; + struct clk *clk; + void __iomem *regs; + unsigned int width; +}; + +static inline struct xilinx_pwm_device *xilinx_pwm_chip_to_device(struct pwm_chip *chip) +{ + return container_of(chip, struct xilinx_pwm_device, chip); +} + +static bool xilinx_pwm_is_enabled(u32 tcsr0, u32 tcsr1) +{ + return !(~tcsr0 & TCSR_SET || tcsr0 & (TCSR_CLEAR | TCSR_CASC) || + ~tcsr1 & TCSR_SET || tcsr1 & TCSR_CLEAR); +} + +static u32 xilinx_pwm_calc_tlr(struct xilinx_pwm_device *pwm, u32 tcsr, + unsigned int period) +{ + u64 cycles = DIV_ROUND_DOWN_ULL(period * clk_get_rate(pwm->clk), + NSEC_PER_SEC_ULL); + + if (tcsr & TCSR_UDT) + return cycles - 2; + else + return (BIT_ULL(pwm->width) - 1) - cycles + 2; +} + +static unsigned int xilinx_pwm_get_period(struct xilinx_pwm_device *pwm, + u32 tlr, u32 tcsr) +{ + u64 cycles; + + if (tcsr & TCSR_UDT) + cycles = tlr + 2; + else + cycles = (BIT_ULL(pwm->width) - 1) - tlr + 2; + + return DIV_ROUND_DOWN_ULL(cycles * NSEC_PER_SEC_ULL, + clk_get_rate(pwm->clk)); +} + +static int xilinx_pwm_apply(struct pwm_chip *chip, struct pwm_device *unused, + const struct pwm_state *state) +{ + struct xilinx_pwm_device *pwm = xilinx_pwm_chip_to_device(chip); + u32 tlr0, tlr1; + u32 tcsr0 = readl(pwm->regs + TCSR0); + u32 tcsr1 = readl(pwm->regs + TCSR1); + bool enabled = xilinx_pwm_is_enabled(tcsr0, tcsr1); + + if (state->polarity != PWM_POLARITY_NORMAL) + return -EINVAL; + + if (!enabled && state->enabled) + clk_rate_exclusive_get(pwm->clk); + + tlr0 = xilinx_pwm_calc_tlr(pwm, tcsr0, state->period); + tlr1 = xilinx_pwm_calc_tlr(pwm, tcsr1, state->duty_cycle); + writel(tlr0, pwm->regs + TLR0); + writel(tlr1, pwm->regs + TLR1); + + if (state->enabled) { + /* Only touch the TCSRs if we aren't already running */ + if (!enabled) { + /* Load TLR into TCR */ + writel(tcsr0 | TCSR_LOAD, pwm->regs + TCSR0); + writel(tcsr1 | TCSR_LOAD, pwm->regs + TCSR1); + /* Enable timers all at once with ENALL */ + tcsr0 = (TCSR_SET & ~TCSR_ENT) | (tcsr0 & TCSR_UDT); + tcsr1 = TCSR_SET | TCSR_ENALL | (tcsr1 & TCSR_UDT); + writel(tcsr0, pwm->regs + TCSR0); + writel(tcsr1, pwm->regs + TCSR1); + } + } else { + writel(tcsr0 & ~TCSR_ENT, pwm->regs + TCSR0); + writel(tcsr1 & ~TCSR_ENT, pwm->regs + TCSR1); + } + + if (enabled && !state->enabled) + clk_rate_exclusive_put(pwm->clk); + + return 0; +} + +static void xilinx_pwm_get_state(struct pwm_chip *chip, + struct pwm_device *unused, + struct pwm_state *state) +{ + struct xilinx_pwm_device *pwm = xilinx_pwm_chip_to_device(chip); + u32 tlr0, tlr1, tcsr0, tcsr1; + + tlr0 = readl(pwm->regs + TLR0); + tlr1 = readl(pwm->regs + TLR1); + tcsr0 = readl(pwm->regs + TCSR0); + tcsr1 = readl(pwm->regs + TCSR1); + + state->period = xilinx_pwm_get_period(pwm, tlr0, tcsr0); + state->duty_cycle = xilinx_pwm_get_period(pwm, tlr1, tcsr1); + state->enabled = xilinx_pwm_is_enabled(tcsr0, tcsr1); + state->polarity = PWM_POLARITY_NORMAL; +} + +static const struct pwm_ops xilinx_pwm_ops = { + .apply = xilinx_pwm_apply, + .get_state = xilinx_pwm_get_state, +}; + +static struct dentry *debug_dir; + +#define DEBUG_REG(reg) { .name = #reg, .offset = (reg), } +static struct debugfs_reg32 xilinx_pwm_reg32[] = { + DEBUG_REG(TCSR0), + DEBUG_REG(TLR0), + DEBUG_REG(TCR0), + DEBUG_REG(TCSR1), + DEBUG_REG(TLR1), + DEBUG_REG(TCR1), +}; + +static int xilinx_pwm_debug_create(struct xilinx_pwm_device *pwm) +{ + struct debugfs_regset32 *regset; + + if (!IS_ENABLED(CONFIG_DEBUG_FS)) + return 0; + + regset = devm_kzalloc(pwm->chip.dev, sizeof(*regset), GFP_KERNEL); + if (!pwm) + return -ENOMEM; + + regset->regs = xilinx_pwm_reg32; + regset->nregs = ARRAY_SIZE(xilinx_pwm_reg32); + regset->base = pwm->regs; + + debugfs_create_regset32(dev_name(pwm->chip.dev), 0400, debug_dir, + regset); + return 0; +} + +static int xilinx_pwm_probe(struct platform_device *pdev) +{ + bool enabled; + int i, ret; + struct device *dev = &pdev->dev; + struct xilinx_pwm_device *pwm; + u32 one_timer; + + ret = of_property_read_u32(dev->of_node, "xlnx,one-timer-only", + &one_timer); + if (ret || one_timer) { + dev_err(dev, "two timers are needed for PWM mode\n"); + return -EINVAL; + } + + for (i = 0; i < 2; i++) { + char fmt[] = "xlnx,gen%u-assert"; + char buf[sizeof(fmt)]; + u32 gen; + + snprintf(buf, sizeof(buf), fmt, i); + ret = of_property_read_u32(dev->of_node, buf, &gen); + if (ret || !gen) { + dev_err(dev, "generateout%u must be active high\n", i); + return -EINVAL; + } + } + + pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL); + if (!pwm) + return -ENOMEM; + platform_set_drvdata(pdev, pwm); + + pwm->chip.dev = &pdev->dev; + pwm->chip.ops = &xilinx_pwm_ops; + pwm->chip.base = -1; + pwm->chip.npwm = 1; + + pwm->regs = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(pwm->regs)) + return PTR_ERR(pwm->regs); + + ret = of_property_read_u32(dev->of_node, "xlnx,count-width", &pwm->width); + if (ret) { + dev_err(dev, "missing counter width\n"); + return -EINVAL; + } + + pwm->clk = devm_clk_get(dev, NULL); + if (IS_ERR(pwm->clk)) + return dev_err_probe(dev, PTR_ERR(pwm->clk), "missing clock\n"); + + ret = clk_prepare_enable(pwm->clk); + if (ret) { + dev_err(dev, "clock enable failed\n"); + return ret; + } + + ret = xilinx_pwm_debug_create(pwm); + if (ret) { + clk_disable_unprepare(pwm->clk); + return ret; + } + + ret = pwmchip_add(&pwm->chip); + if (ret) { + clk_disable_unprepare(pwm->clk); + return ret; + } + + enabled = xilinx_pwm_is_enabled(readl(pwm->regs + TCSR0), + readl(pwm->regs + TCSR1)); + if (enabled) + clk_rate_exclusive_get(pwm->clk); + + return ret; +} + +static int xilinx_pwm_remove(struct platform_device *pdev) +{ + struct xilinx_pwm_device *pwm = platform_get_drvdata(pdev); + bool enabled = xilinx_pwm_is_enabled(readl(pwm->regs + TCSR0), + readl(pwm->regs + TCSR1)); + + if (enabled) + clk_rate_exclusive_put(pwm->clk); + clk_disable_unprepare(pwm->clk); + return pwmchip_remove(&pwm->chip); +} + +static const struct of_device_id xilinx_pwm_of_match[] = { + { .compatible = "xlnx,xps-timer-1.00.a" }, + { .compatible = "xlnx,axi-timer-2.0" }, + {}, +}; +MODULE_DEVICE_TABLE(of, xilinx_pwm_of_match); + +static struct platform_driver xilinx_pwm_driver = { + .probe = xilinx_pwm_probe, + .remove = xilinx_pwm_remove, + .driver = { + .name = "xilinx-pwm", + .of_match_table = of_match_ptr(xilinx_pwm_of_match), + }, +}; + +static int __init xilinx_pwm_init(void) +{ + int ret = platform_driver_register(&xilinx_pwm_driver); + + if (ret) + return ret; + + if (IS_ENABLED(CONFIG_DEBUG_FS)) { + debug_dir = debugfs_create_dir(xilinx_pwm_driver.driver.name, NULL); + if (IS_ERR(debug_dir)) { + platform_driver_unregister(&xilinx_pwm_driver); + return PTR_ERR(debug_dir); + } + } + return 0; +} +module_init(xilinx_pwm_init); + +static void __exit xilinx_pwm_exit(void) +{ + platform_driver_unregister(&xilinx_pwm_driver); + if (IS_ENABLED(CONFIG_DEBUG_FS)) + debugfs_remove_recursive(debug_dir); +} +module_exit(xilinx_pwm_exit); + +MODULE_ALIAS("platform:xilinx-pwm"); +MODULE_DESCRIPTION("Xilinx LogiCORE IP AXI Timer PWM driver"); +MODULE_LICENSE("GPL v2"); -- 2.25.1
