--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Analog Devices AXI PWM generator
+ *
+ * Copyright 2024 Analog Devices Inc.
+ * Copyright 2024 Baylibre SAS
+ *
+ * Device docs: https://analogdevicesinc.github.io/hdl/library/axi_pwm_gen/index.html
+ *
+ * Limitations:
+ * - The writes to registers for period and duty are shadowed until
+ * LOAD_CONFIG is written to AXI_PWMGEN_REG_CONFIG, at which point
+ * they take effect.
+ * - Writing LOAD_CONFIG also has the effect of re-synchronizing all
+ * enabled channels, which could cause glitching on other channels. It
+ * is therefore expected that channels are assigned harmonic periods
+ * and all have a single user coordinating this.
+ * - Supports normal polarity. Does not support changing polarity.
+ * - On disable, the PWM output becomes low (inactive).
+ */
+#include <linux/bits.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/fpga/adi-axi-common.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#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_CHX_PERIOD(ch) (0x40 + (4 * (ch)))
+#define AXI_PWMGEN_CHX_DUTY(ch) (0x80 + (4 * (ch)))
+#define AXI_PWMGEN_CHX_OFFSET(ch) (0xC0 + (4 * (ch)))
+#define AXI_PWMGEN_REG_CORE_MAGIC_VAL 0x601A3471 /* Identification number to test during setup */
+#define AXI_PWMGEN_LOAD_CONFIG BIT(1)
+#define AXI_PWMGEN_REG_CONFIG_RESET BIT(0)
+
+struct axi_pwmgen_ddata {
+ struct regmap *regmap;
+ unsigned long clk_rate_hz;
+};
+
+static const struct regmap_config axi_pwmgen_regmap_config = {
+ .reg_bits = 32,
+ .reg_stride = 4,
+ .val_bits = 32,
+};
+
+static int axi_pwmgen_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+ const struct pwm_state *state)
+{
+ struct axi_pwmgen_ddata *ddata = pwmchip_get_drvdata(chip);
+ unsigned int ch = pwm->hwpwm;
+ struct regmap *regmap = ddata->regmap;
+ u64 period_cnt, duty_cnt;
+ int ret;
+
+ if (state->polarity != PWM_POLARITY_NORMAL)
+ return -EINVAL;
+
+ if (state->enabled) {
+ period_cnt = mul_u64_u64_div_u64(state->period, ddata->clk_rate_hz, NSEC_PER_SEC);
+ if (period_cnt > UINT_MAX)
+ period_cnt = UINT_MAX;
+
+ if (period_cnt == 0)
+ return -EINVAL;
+
+ ret = regmap_write(regmap, AXI_PWMGEN_CHX_PERIOD(ch), period_cnt);
+ if (ret)
+ return ret;
+
+ duty_cnt = mul_u64_u64_div_u64(state->duty_cycle, ddata->clk_rate_hz, NSEC_PER_SEC);
+ if (duty_cnt > UINT_MAX)
+ duty_cnt = UINT_MAX;
+
+ ret = regmap_write(regmap, AXI_PWMGEN_CHX_DUTY(ch), duty_cnt);
+ if (ret)
+ return ret;
+ } else {
+ ret = regmap_write(regmap, AXI_PWMGEN_CHX_PERIOD(ch), 0);
+ if (ret)
+ return ret;
+
+ ret = regmap_write(regmap, AXI_PWMGEN_CHX_DUTY(ch), 0);
+ if (ret)
+ return ret;
+ }
+
+ return regmap_write(regmap, AXI_PWMGEN_REG_CONFIG, AXI_PWMGEN_LOAD_CONFIG);
+}
+
+static int axi_pwmgen_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+ struct pwm_state *state)
+{
+ struct axi_pwmgen_ddata *ddata = pwmchip_get_drvdata(chip);
+ struct regmap *regmap = ddata->regmap;
+ unsigned int ch = pwm->hwpwm;
+ u32 cnt;
+ int ret;
+
+ ret = regmap_read(regmap, AXI_PWMGEN_CHX_PERIOD(ch), &cnt);
+ if (ret)
+ return ret;
+
+ state->enabled = cnt != 0;
+
+ state->period = DIV_ROUND_UP_ULL((u64)cnt * NSEC_PER_SEC, ddata->clk_rate_hz);
+
+ ret = regmap_read(regmap, AXI_PWMGEN_CHX_DUTY(ch), &cnt);
+ if (ret)
+ return ret;
+
+ state->duty_cycle = DIV_ROUND_UP_ULL((u64)cnt * NSEC_PER_SEC, ddata->clk_rate_hz);
+
+ state->polarity = PWM_POLARITY_NORMAL;
+
+ 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 regmap *regmap, struct device *dev)
+{
+ int ret;
+ u32 val;
+
+ ret = regmap_read(regmap, AXI_PWMGEN_REG_CORE_MAGIC, &val);
+ if (ret)
+ return ret;
+
+ if (val != AXI_PWMGEN_REG_CORE_MAGIC_VAL)
+ return dev_err_probe(dev, -ENODEV,
+ "failed to read expected value from register: got %08x, expected %08x\n",
+ val, AXI_PWMGEN_REG_CORE_MAGIC_VAL);
+
+ ret = regmap_read(regmap, AXI_PWMGEN_REG_CORE_VERSION, &val);
+ if (ret)
+ return ret;
+
+ if (ADI_AXI_PCORE_VER_MAJOR(val) != 2) {
+ return dev_err_probe(dev, -ENODEV, "Unsupported peripheral version %u.%u.%u\n",
+ ADI_AXI_PCORE_VER_MAJOR(val),
+ ADI_AXI_PCORE_VER_MINOR(val),
+ ADI_AXI_PCORE_VER_PATCH(val));
+ }
+
+ /* Enable the core */
+ ret = regmap_update_bits(regmap, AXI_PWMGEN_REG_CONFIG, AXI_PWMGEN_REG_CONFIG_RESET, 0);
+ if (ret)
+ return ret;
+
+ ret = regmap_read(regmap, AXI_PWMGEN_REG_NPWM, &val);
+ if (ret)
+ return ret;
+
+ /* Return the number of PWMs */
+ return val;
+}
+
+static int axi_pwmgen_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct regmap *regmap;
+ struct pwm_chip *chip;
+ struct axi_pwmgen_ddata *ddata;
+ struct clk *clk;
+ void __iomem *io_base;
+ int ret;
+
+ io_base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(io_base))
+ return PTR_ERR(io_base);
+
+ regmap = devm_regmap_init_mmio(dev, io_base, &axi_pwmgen_regmap_config);
+ if (IS_ERR(regmap))
+ return dev_err_probe(dev, PTR_ERR(regmap),
+ "failed to init register map\n");
+
+ ret = axi_pwmgen_setup(regmap, dev);
+ if (ret < 0)
+ return ret;
+
+ chip = devm_pwmchip_alloc(dev, ret, sizeof(*ddata));
+ if (IS_ERR(chip))
+ return PTR_ERR(chip);
+ ddata = pwmchip_get_drvdata(chip);
+ ddata->regmap = regmap;
+
+ clk = devm_clk_get_enabled(dev, NULL);
+ if (IS_ERR(clk))
+ return dev_err_probe(dev, PTR_ERR(clk), "failed to get clock\n");
+
+ ret = devm_clk_rate_exclusive_get(dev, clk);
+ if (ret)
+ return dev_err_probe(dev, ret, "failed to get exclusive rate\n");
+
+ ddata->clk_rate_hz = clk_get_rate(clk);
+ if (!ddata->clk_rate_hz || ddata->clk_rate_hz > NSEC_PER_SEC)
+ return dev_err_probe(dev, -EINVAL,
+ "Invalid clock rate: %lu\n", ddata->clk_rate_hz);
+
+ chip->ops = &axi_pwmgen_pwm_ops;
+ chip->atomic = true;
+
+ ret = devm_pwmchip_add(dev, chip);
+ if (ret)
+ return dev_err_probe(dev, ret, "could not add PWM chip\n");
+
+ return 0;
+}
+
+static const struct of_device_id axi_pwmgen_ids[] = {
+ { .compatible = "adi,axi-pwmgen-2.00.a" },
+ { }
+};
+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 <sergiu.cuciurean@analog.com>");
+MODULE_AUTHOR("Trevor Gamblin <tgamblin@baylibre.com>");
+MODULE_DESCRIPTION("Driver for the Analog Devices AXI PWM generator");
projects / thirdparty / kernel / linux.git / commitdiff
