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Thu, 13 Feb 2025 01:41:04 -0800 (PST) From: Aleksandr Shubin To: linux-kernel@vger.kernel.org Cc: Aleksandr Shubin , Brandon Cheo Fusi , =?utf-8?q?Uwe_Kleine-K=C3=B6ni?= =?utf-8?q?g?= , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Chen-Yu Tsai , Jernej Skrabec , Samuel Holland , Paul Walmsley , Palmer Dabbelt , Albert Ou , Philipp Zabel , linux-pwm@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-sunxi@lists.linux.dev, linux-riscv@lists.infradead.org Subject: [PATCH v11 2/3] pwm: Add Allwinner's D1/T113-S3/R329 SoCs PWM support Date: Thu, 13 Feb 2025 12:40:13 +0300 Message-Id: <20250213094018.134081-3-privatesub2@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20250213094018.134081-1-privatesub2@gmail.com> References: <20250213094018.134081-1-privatesub2@gmail.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250213_014106_889853_295B78A3 X-CRM114-Status: GOOD ( 30.70 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org Allwinner's D1, T113-S3 and R329 SoCs have a quite different PWM controllers with ones supported by pwm-sun4i driver. This patch adds a PWM controller driver for Allwinner's D1, T113-S3 and R329 SoCs. The main difference between these SoCs is the number of channels defined by the DT property. Co-developed-by: Brandon Cheo Fusi Signed-off-by: Brandon Cheo Fusi Signed-off-by: Aleksandr Shubin --- drivers/pwm/Kconfig | 10 ++ drivers/pwm/Makefile | 1 + drivers/pwm/pwm-sun20i.c | 370 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 381 insertions(+) create mode 100644 drivers/pwm/pwm-sun20i.c diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index 0915c1e7df16..778151aa3860 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -652,6 +652,16 @@ config PWM_SUN4I To compile this driver as a module, choose M here: the module will be called pwm-sun4i. +config PWM_SUN20I + tristate "Allwinner D1/T113s/R329 PWM support" + depends on ARCH_SUNXI || COMPILE_TEST + depends on COMMON_CLK + help + Generic PWM framework driver for Allwinner D1/T113s/R329 SoCs. + + To compile this driver as a module, choose M here: the module + will be called pwm-sun20i. + config PWM_SUNPLUS tristate "Sunplus PWM support" depends on ARCH_SUNPLUS || COMPILE_TEST diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index 9081e0c0e9e0..85ad1fe0dde1 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -60,6 +60,7 @@ obj-$(CONFIG_PWM_STM32) += pwm-stm32.o obj-$(CONFIG_PWM_STM32_LP) += pwm-stm32-lp.o obj-$(CONFIG_PWM_STMPE) += pwm-stmpe.o obj-$(CONFIG_PWM_SUN4I) += pwm-sun4i.o +obj-$(CONFIG_PWM_SUN20I) += pwm-sun20i.o obj-$(CONFIG_PWM_SUNPLUS) += pwm-sunplus.o obj-$(CONFIG_PWM_TEGRA) += pwm-tegra.o obj-$(CONFIG_PWM_TIECAP) += pwm-tiecap.o diff --git a/drivers/pwm/pwm-sun20i.c b/drivers/pwm/pwm-sun20i.c new file mode 100644 index 000000000000..409fa8e9bc45 --- /dev/null +++ b/drivers/pwm/pwm-sun20i.c @@ -0,0 +1,370 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * PWM Controller Driver for sunxi platforms (D1, T113-S3 and R329) + * + * Limitations: + * - When the parameters change, the current running period is not completed + * and new settings are applied immediately. + * - The PWM output goes to a HIGH-Z state when the channel is disabled. + * - Changing the clock configuration (SUN20I_PWM_CLK_CFG) + * - may cause a brief output glitch. + * + * Copyright (c) 2023 Aleksandr Shubin + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define SUN20I_PWM_CLK_CFG(pair) (0x20 + ((pair) * 0x4)) +#define SUN20I_PWM_CLK_CFG_SRC GENMASK(8, 7) +#define SUN20I_PWM_CLK_CFG_DIV_M GENMASK(3, 0) +#define SUN20I_PWM_CLK_DIV_M_MAX 8 + +#define SUN20I_PWM_CLK_GATE 0x40 +#define SUN20I_PWM_CLK_GATE_BYPASS(chan) BIT((chan) + 16) +#define SUN20I_PWM_CLK_GATE_GATING(chan) BIT(chan) + +#define SUN20I_PWM_ENABLE 0x80 +#define SUN20I_PWM_ENABLE_EN(chan) BIT(chan) + +#define SUN20I_PWM_CTL(chan) (0x100 + (chan) * 0x20) +#define SUN20I_PWM_CTL_ACT_STA BIT(8) +#define SUN20I_PWM_CTL_PRESCAL_K GENMASK(7, 0) +#define SUN20I_PWM_CTL_PRESCAL_K_MAX field_max(SUN20I_PWM_CTL_PRESCAL_K) + +#define SUN20I_PWM_PERIOD(chan) (0x104 + (chan) * 0x20) +#define SUN20I_PWM_PERIOD_ENTIRE_CYCLE GENMASK(31, 16) +#define SUN20I_PWM_PERIOD_ACT_CYCLE GENMASK(15, 0) + +#define SUN20I_PWM_PCNTR_SIZE BIT(16) + +/* + * SUN20I_PWM_MAGIC is used to quickly compute the values of the clock dividers + * div_m (SUN20I_PWM_CLK_CFG_DIV_M) & prescale_k (SUN20I_PWM_CTL_PRESCAL_K) + * without using a loop. These dividers limit the # of cycles in a period + * to SUN20I_PWM_PCNTR_SIZE (65536) by applying a scaling factor of + * 1/(div_m * (prescale_k + 1)) to the clock source. + * + * SUN20I_PWM_MAGIC is derived by solving for div_m and prescale_k + * such that for a given requested period, + * + * i) div_m is minimized for any prescale_k ≤ SUN20I_PWM_CTL_PRESCAL_K_MAX, + * ii) prescale_k is minimized. + * + * The derivation proceeds as follows, with val = # of cycles for requested + * period: + * + * for a given value of div_m we want the smallest prescale_k such that + * + * (val >> div_m) // (prescale_k + 1) ≤ 65536 (= SUN20I_PWM_PCNTR_SIZE) + * + * This is equivalent to: + * + * (val >> div_m) ≤ 65536 * (prescale_k + 1) + prescale_k + * ⟺ (val >> div_m) ≤ 65537 * prescale_k + 65536 + * ⟺ (val >> div_m) - 65536 ≤ 65537 * prescale_k + * ⟺ ((val >> div_m) - 65536) / 65537 ≤ prescale_k + * + * As prescale_k is integer, this becomes + * + * ((val >> div_m) - 65536) // 65537 ≤ prescale_k + * + * And is minimized at + * + * ((val >> div_m) - 65536) // 65537 + * + * Now we pick the smallest div_m that satifies prescale_k ≤ 255 + * (i.e SUN20I_PWM_CTL_PRESCAL_K_MAX), + * + * ((val >> div_m) - 65536) // 65537 ≤ 255 + * ⟺ (val >> div_m) - 65536 ≤ 255 * 65537 + 65536 + * ⟺ val >> div_m ≤ 255 * 65537 + 2 * 65536 + * ⟺ val >> div_m < (255 * 65537 + 2 * 65536 + 1) + * ⟺ div_m = fls((val) / (255 * 65537 + 2 * 65536 + 1)) + * + * Suggested by Uwe Kleine-König + */ +#define SUN20I_PWM_MAGIC (255 * 65537 + 2 * 65536 + 1) +#define SUN20I_PWM_DIV_CONST 65537 + +struct sun20i_pwm_chip { + struct clk *clk_hosc, *clk_apb; + void __iomem *base; +}; + +static inline struct sun20i_pwm_chip *to_sun20i_pwm_chip(struct pwm_chip *chip) +{ + return pwmchip_get_drvdata(chip); +} + +static inline u32 sun20i_pwm_readl(struct sun20i_pwm_chip *chip, + unsigned long offset) +{ + return readl(chip->base + offset); +} + +static inline void sun20i_pwm_writel(struct sun20i_pwm_chip *chip, + u32 val, unsigned long offset) +{ + writel(val, chip->base + offset); +} + +static int sun20i_pwm_get_state(struct pwm_chip *chip, + struct pwm_device *pwm, + struct pwm_state *state) +{ + struct sun20i_pwm_chip *sun20i_chip = to_sun20i_pwm_chip(chip); + u16 ent_cycle, act_cycle, prescale_k; + u64 clk_rate, tmp; + u8 div_m; + u32 val; + + val = sun20i_pwm_readl(sun20i_chip, SUN20I_PWM_CLK_CFG(pwm->hwpwm / 2)); + div_m = FIELD_GET(SUN20I_PWM_CLK_CFG_DIV_M, val); + if (div_m > SUN20I_PWM_CLK_DIV_M_MAX) + div_m = SUN20I_PWM_CLK_DIV_M_MAX; + + /* + * If CLK_CFG_SRC is 0, use the hosc clock; + * otherwise (any nonzero value) use the APB clock. + */ + if (FIELD_GET(SUN20I_PWM_CLK_CFG_SRC, val) == 0) + clk_rate = clk_get_rate(sun20i_chip->clk_hosc); + else + clk_rate = clk_get_rate(sun20i_chip->clk_apb); + + val = sun20i_pwm_readl(sun20i_chip, SUN20I_PWM_CTL(pwm->hwpwm)); + state->polarity = (SUN20I_PWM_CTL_ACT_STA & val) ? + PWM_POLARITY_NORMAL : PWM_POLARITY_INVERSED; + + prescale_k = FIELD_GET(SUN20I_PWM_CTL_PRESCAL_K, val) + 1; + + val = sun20i_pwm_readl(sun20i_chip, SUN20I_PWM_ENABLE); + state->enabled = (SUN20I_PWM_ENABLE_EN(pwm->hwpwm) & val) ? true : false; + + val = sun20i_pwm_readl(sun20i_chip, SUN20I_PWM_PERIOD(pwm->hwpwm)); + + act_cycle = FIELD_GET(SUN20I_PWM_PERIOD_ACT_CYCLE, val); + ent_cycle = FIELD_GET(SUN20I_PWM_PERIOD_ENTIRE_CYCLE, val); + + /* + * The duration of the active phase should not be longer + * than the duration of the period + */ + if (act_cycle > ent_cycle) + act_cycle = ent_cycle; + + /* + * We have act_cycle <= ent_cycle <= 0xffff, prescale_k <= 0x100, + * div_m <= 8. So the multiplication fits into an u64 without + * overflow. + */ + tmp = ((u64)(act_cycle) * prescale_k << div_m) * NSEC_PER_SEC; + state->duty_cycle = DIV_ROUND_UP_ULL(tmp, clk_rate); + tmp = ((u64)(ent_cycle) * prescale_k << div_m) * NSEC_PER_SEC; + state->period = DIV_ROUND_UP_ULL(tmp, clk_rate); + + return 0; +} + +static int sun20i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, + const struct pwm_state *state) +{ + struct sun20i_pwm_chip *sun20i_chip = to_sun20i_pwm_chip(chip); + u64 bus_rate, hosc_rate, val, ent_cycle, act_cycle; + u32 clk_gate, clk_cfg, pwm_en, ctl, reg_period; + u32 prescale_k, div_m; + bool use_bus_clk; + + pwm_en = sun20i_pwm_readl(sun20i_chip, SUN20I_PWM_ENABLE); + + if (state->enabled != pwm->state.enabled) { + clk_gate = sun20i_pwm_readl(sun20i_chip, SUN20I_PWM_CLK_GATE); + + if (!state->enabled) { + clk_gate &= ~SUN20I_PWM_CLK_GATE_GATING(pwm->hwpwm); + pwm_en &= ~SUN20I_PWM_ENABLE_EN(pwm->hwpwm); + sun20i_pwm_writel(sun20i_chip, pwm_en, SUN20I_PWM_ENABLE); + sun20i_pwm_writel(sun20i_chip, clk_gate, SUN20I_PWM_CLK_GATE); + + return 0; + } + } + + ctl = sun20i_pwm_readl(sun20i_chip, SUN20I_PWM_CTL(pwm->hwpwm)); + clk_cfg = sun20i_pwm_readl(sun20i_chip, SUN20I_PWM_CLK_CFG(pwm->hwpwm / 2)); + hosc_rate = clk_get_rate(sun20i_chip->clk_hosc); + bus_rate = clk_get_rate(sun20i_chip->clk_apb); + if (pwm_en & SUN20I_PWM_ENABLE_EN(pwm->hwpwm ^ 1)) { + /* If the neighbor channel is enabled, use the current clock settings */ + use_bus_clk = FIELD_GET(SUN20I_PWM_CLK_CFG_SRC, clk_cfg) != 0; + val = mul_u64_u64_div_u64(state->period, + (use_bus_clk ? bus_rate : hosc_rate), + NSEC_PER_SEC); + + div_m = FIELD_GET(SUN20I_PWM_CLK_CFG_DIV_M, clk_cfg); + } else { + /* + * Select the clock source based on the period. + * Since bus_rate > hosc_rate, which means bus_rate + * can provide a higher frequency than hosc_rate. + */ + use_bus_clk = false; + val = mul_u64_u64_div_u64(state->period, hosc_rate, NSEC_PER_SEC); + /* + * If the calculated value is ≤ 1, the period is too short + * for proper PWM operation + */ + if (val <= 1) { + use_bus_clk = true; + val = mul_u64_u64_div_u64(state->period, bus_rate, NSEC_PER_SEC); + if (val <= 1) + return -EINVAL; + } + div_m = fls(DIV_ROUND_DOWN_ULL(val, SUN20I_PWM_MAGIC)); + if (div_m > SUN20I_PWM_CLK_DIV_M_MAX) + return -EINVAL; + + /* Set up the CLK_DIV_M and clock CLK_SRC */ + clk_cfg = FIELD_PREP(SUN20I_PWM_CLK_CFG_DIV_M, div_m); + clk_cfg |= FIELD_PREP(SUN20I_PWM_CLK_CFG_SRC, use_bus_clk); + + sun20i_pwm_writel(sun20i_chip, clk_cfg, SUN20I_PWM_CLK_CFG(pwm->hwpwm / 2)); + } + + /* Calculate prescale_k and determine the number of cycles for a full PWM period */ + ent_cycle = val >> div_m; + prescale_k = DIV_ROUND_DOWN_ULL(ent_cycle, SUN20I_PWM_DIV_CONST); + if (prescale_k > SUN20I_PWM_CTL_PRESCAL_K_MAX) + prescale_k = SUN20I_PWM_CTL_PRESCAL_K_MAX; + + /* ent_cycle must not be zero */ + if (ent_cycle == 0) + return -EINVAL; + do_div(ent_cycle, prescale_k + 1); + + /* For N cycles, PPRx.PWM_ENTIRE_CYCLE = (N-1) */ + reg_period = FIELD_PREP(SUN20I_PWM_PERIOD_ENTIRE_CYCLE, ent_cycle - 1); + + /* Calculate the active cycles (duty cycle) */ + val = mul_u64_u64_div_u64(state->duty_cycle, + (use_bus_clk ? bus_rate : hosc_rate), + NSEC_PER_SEC); + act_cycle = val >> div_m; + do_div(act_cycle, prescale_k + 1); + + /* + * The formula of the output period and the duty-cycle for PWM are as follows. + * T period = PWM0_PRESCALE_K / PWM01_CLK * (PPR0.PWM_ENTIRE_CYCLE + 1) + * T high-level = PWM0_PRESCALE_K / PWM01_CLK * PPR0.PWM_ACT_CYCLE + * Duty-cycle = T high-level / T period + */ + reg_period |= FIELD_PREP(SUN20I_PWM_PERIOD_ACT_CYCLE, act_cycle); + sun20i_pwm_writel(sun20i_chip, reg_period, SUN20I_PWM_PERIOD(pwm->hwpwm)); + + ctl = FIELD_PREP(SUN20I_PWM_CTL_PRESCAL_K, prescale_k); + if (state->polarity == PWM_POLARITY_NORMAL) + ctl |= SUN20I_PWM_CTL_ACT_STA; + + sun20i_pwm_writel(sun20i_chip, ctl, SUN20I_PWM_CTL(pwm->hwpwm)); + + if (state->enabled != pwm->state.enabled) { + clk_gate &= ~SUN20I_PWM_CLK_GATE_BYPASS(pwm->hwpwm); + clk_gate |= SUN20I_PWM_CLK_GATE_GATING(pwm->hwpwm); + pwm_en |= SUN20I_PWM_ENABLE_EN(pwm->hwpwm); + sun20i_pwm_writel(sun20i_chip, pwm_en, SUN20I_PWM_ENABLE); + sun20i_pwm_writel(sun20i_chip, clk_gate, SUN20I_PWM_CLK_GATE); + } + + return 0; +} + +static const struct pwm_ops sun20i_pwm_ops = { + .apply = sun20i_pwm_apply, + .get_state = sun20i_pwm_get_state, +}; + +static const struct of_device_id sun20i_pwm_dt_ids[] = { + { .compatible = "allwinner,sun20i-d1-pwm" }, + { } +}; +MODULE_DEVICE_TABLE(of, sun20i_pwm_dt_ids); + +static int sun20i_pwm_probe(struct platform_device *pdev) +{ + struct pwm_chip *chip; + struct sun20i_pwm_chip *sun20i_chip; + struct clk *clk_bus; + struct reset_control *rst; + u32 npwm; + int ret; + + ret = of_property_read_u32(pdev->dev.of_node, "allwinner,npwms", &npwm); + if (ret < 0) + npwm = 8; /* Default value */ + + if (npwm > 16) { + dev_info(&pdev->dev, "Limiting number of PWM lines from %u to 16", npwm); + npwm = 16; + } + + chip = devm_pwmchip_alloc(&pdev->dev, npwm, sizeof(*sun20i_chip)); + if (IS_ERR(chip)) + return PTR_ERR(chip); + sun20i_chip = to_sun20i_pwm_chip(chip); + + sun20i_chip->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(sun20i_chip->base)) + return PTR_ERR(sun20i_chip->base); + + clk_bus = devm_clk_get_enabled(&pdev->dev, "bus"); + if (IS_ERR(clk_bus)) + return dev_err_probe(&pdev->dev, PTR_ERR(clk_bus), + "Failed to get bus clock\n"); + + sun20i_chip->clk_hosc = devm_clk_get_enabled(&pdev->dev, "hosc"); + if (IS_ERR(sun20i_chip->clk_hosc)) + return dev_err_probe(&pdev->dev, PTR_ERR(sun20i_chip->clk_hosc), + "Failed to get hosc clock\n"); + + sun20i_chip->clk_apb = devm_clk_get_enabled(&pdev->dev, "apb"); + if (IS_ERR(sun20i_chip->clk_apb)) + return dev_err_probe(&pdev->dev, PTR_ERR(sun20i_chip->clk_apb), + "Failed to get apb clock\n"); + + if (clk_get_rate(sun20i_chip->clk_apb) <= clk_get_rate(sun20i_chip->clk_hosc)) + dev_info(&pdev->dev, "APB clock must be greater than hosc clock"); + + rst = devm_reset_control_get_exclusive_deasserted(&pdev->dev, NULL); + if (IS_ERR(rst)) + return dev_err_probe(&pdev->dev, PTR_ERR(rst), + "Failed to get reset control\n"); + + chip->ops = &sun20i_pwm_ops; + + ret = devm_pwmchip_add(&pdev->dev, chip); + if (ret < 0) + return dev_err_probe(&pdev->dev, ret, "Failed to add PWM chip\n"); + + return 0; +} + +static struct platform_driver sun20i_pwm_driver = { + .driver = { + .name = "sun20i-pwm", + .of_match_table = sun20i_pwm_dt_ids, + }, + .probe = sun20i_pwm_probe, +}; +module_platform_driver(sun20i_pwm_driver); + +MODULE_AUTHOR("Aleksandr Shubin "); +MODULE_DESCRIPTION("Allwinner sun20i PWM driver"); +MODULE_LICENSE("GPL");