diff options
| -rw-r--r-- | drivers/pwm/Kconfig | 11 | ||||
| -rw-r--r-- | drivers/pwm/Makefile | 1 | ||||
| -rw-r--r-- | drivers/pwm/pwm-sprd.c | 309 |
3 files changed, 321 insertions, 0 deletions
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index a7e57516959e..31dfc88ef362 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -423,6 +423,17 @@ config PWM_SPEAR To compile this driver as a module, choose M here: the module will be called pwm-spear. +config PWM_SPRD + tristate "Spreadtrum PWM support" + depends on ARCH_SPRD || COMPILE_TEST + depends on HAS_IOMEM + help + Generic PWM framework driver for the PWM controller on + Spreadtrum SoCs. + + To compile this driver as a module, choose M here: the module + will be called pwm-sprd. + config PWM_STI tristate "STiH4xx PWM support" depends on ARCH_STI diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index 76b555b51887..26326adf71d7 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -41,6 +41,7 @@ obj-$(CONFIG_PWM_ROCKCHIP) += pwm-rockchip.o obj-$(CONFIG_PWM_SAMSUNG) += pwm-samsung.o obj-$(CONFIG_PWM_SIFIVE) += pwm-sifive.o obj-$(CONFIG_PWM_SPEAR) += pwm-spear.o +obj-$(CONFIG_PWM_SPRD) += pwm-sprd.o obj-$(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-sprd.c b/drivers/pwm/pwm-sprd.c new file mode 100644 index 000000000000..68c2d9f0411b --- /dev/null +++ b/drivers/pwm/pwm-sprd.c @@ -0,0 +1,309 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2019 Spreadtrum Communications Inc. + */ + +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/math64.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/pwm.h> + +#define SPRD_PWM_PRESCALE 0x0 +#define SPRD_PWM_MOD 0x4 +#define SPRD_PWM_DUTY 0x8 +#define SPRD_PWM_ENABLE 0x18 + +#define SPRD_PWM_MOD_MAX GENMASK(7, 0) +#define SPRD_PWM_DUTY_MSK GENMASK(15, 0) +#define SPRD_PWM_PRESCALE_MSK GENMASK(7, 0) +#define SPRD_PWM_ENABLE_BIT BIT(0) + +#define SPRD_PWM_CHN_NUM 4 +#define SPRD_PWM_REGS_SHIFT 5 +#define SPRD_PWM_CHN_CLKS_NUM 2 +#define SPRD_PWM_CHN_OUTPUT_CLK 1 + +struct sprd_pwm_chn { + struct clk_bulk_data clks[SPRD_PWM_CHN_CLKS_NUM]; + u32 clk_rate; +}; + +struct sprd_pwm_chip { + void __iomem *base; + struct device *dev; + struct pwm_chip chip; + int num_pwms; + struct sprd_pwm_chn chn[SPRD_PWM_CHN_NUM]; +}; + +/* + * The list of clocks required by PWM channels, and each channel has 2 clocks: + * enable clock and pwm clock. + */ +static const char * const sprd_pwm_clks[] = { + "enable0", "pwm0", + "enable1", "pwm1", + "enable2", "pwm2", + "enable3", "pwm3", +}; + +static u32 sprd_pwm_read(struct sprd_pwm_chip *spc, u32 hwid, u32 reg) +{ + u32 offset = reg + (hwid << SPRD_PWM_REGS_SHIFT); + + return readl_relaxed(spc->base + offset); +} + +static void sprd_pwm_write(struct sprd_pwm_chip *spc, u32 hwid, + u32 reg, u32 val) +{ + u32 offset = reg + (hwid << SPRD_PWM_REGS_SHIFT); + + writel_relaxed(val, spc->base + offset); +} + +static void sprd_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm, + struct pwm_state *state) +{ + struct sprd_pwm_chip *spc = + container_of(chip, struct sprd_pwm_chip, chip); + struct sprd_pwm_chn *chn = &spc->chn[pwm->hwpwm]; + u32 val, duty, prescale; + u64 tmp; + int ret; + + /* + * The clocks to PWM channel has to be enabled first before + * reading to the registers. + */ + ret = clk_bulk_prepare_enable(SPRD_PWM_CHN_CLKS_NUM, chn->clks); + if (ret) { + dev_err(spc->dev, "failed to enable pwm%u clocks\n", + pwm->hwpwm); + return; + } + + val = sprd_pwm_read(spc, pwm->hwpwm, SPRD_PWM_ENABLE); + if (val & SPRD_PWM_ENABLE_BIT) + state->enabled = true; + else + state->enabled = false; + + /* + * The hardware provides a counter that is feed by the source clock. + * The period length is (PRESCALE + 1) * MOD counter steps. + * The duty cycle length is (PRESCALE + 1) * DUTY counter steps. + * Thus the period_ns and duty_ns calculation formula should be: + * period_ns = NSEC_PER_SEC * (prescale + 1) * mod / clk_rate + * duty_ns = NSEC_PER_SEC * (prescale + 1) * duty / clk_rate + */ + val = sprd_pwm_read(spc, pwm->hwpwm, SPRD_PWM_PRESCALE); + prescale = val & SPRD_PWM_PRESCALE_MSK; + tmp = (prescale + 1) * NSEC_PER_SEC * SPRD_PWM_MOD_MAX; + state->period = DIV_ROUND_CLOSEST_ULL(tmp, chn->clk_rate); + + val = sprd_pwm_read(spc, pwm->hwpwm, SPRD_PWM_DUTY); + duty = val & SPRD_PWM_DUTY_MSK; + tmp = (prescale + 1) * NSEC_PER_SEC * duty; + state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, chn->clk_rate); + + /* Disable PWM clocks if the PWM channel is not in enable state. */ + if (!state->enabled) + clk_bulk_disable_unprepare(SPRD_PWM_CHN_CLKS_NUM, chn->clks); +} + +static int sprd_pwm_config(struct sprd_pwm_chip *spc, struct pwm_device *pwm, + int duty_ns, int period_ns) +{ + struct sprd_pwm_chn *chn = &spc->chn[pwm->hwpwm]; + u32 prescale, duty; + u64 tmp; + + /* + * The hardware provides a counter that is feed by the source clock. + * The period length is (PRESCALE + 1) * MOD counter steps. + * The duty cycle length is (PRESCALE + 1) * DUTY counter steps. + * + * To keep the maths simple we're always using MOD = SPRD_PWM_MOD_MAX. + * The value for PRESCALE is selected such that the resulting period + * gets the maximal length not bigger than the requested one with the + * given settings (MOD = SPRD_PWM_MOD_MAX and input clock). + */ + duty = duty_ns * SPRD_PWM_MOD_MAX / period_ns; + + tmp = (u64)chn->clk_rate * period_ns; + do_div(tmp, NSEC_PER_SEC); + prescale = DIV_ROUND_CLOSEST_ULL(tmp, SPRD_PWM_MOD_MAX) - 1; + if (prescale > SPRD_PWM_PRESCALE_MSK) + prescale = SPRD_PWM_PRESCALE_MSK; + + /* + * Note: Writing DUTY triggers the hardware to actually apply the + * values written to MOD and DUTY to the output, so must keep writing + * DUTY last. + * + * The hardware can ensures that current running period is completed + * before changing a new configuration to avoid mixed settings. + */ + sprd_pwm_write(spc, pwm->hwpwm, SPRD_PWM_PRESCALE, prescale); + sprd_pwm_write(spc, pwm->hwpwm, SPRD_PWM_MOD, SPRD_PWM_MOD_MAX); + sprd_pwm_write(spc, pwm->hwpwm, SPRD_PWM_DUTY, duty); + + return 0; +} + +static int sprd_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, + struct pwm_state *state) +{ + struct sprd_pwm_chip *spc = + container_of(chip, struct sprd_pwm_chip, chip); + struct sprd_pwm_chn *chn = &spc->chn[pwm->hwpwm]; + struct pwm_state *cstate = &pwm->state; + int ret; + + if (state->enabled) { + if (!cstate->enabled) { + /* + * The clocks to PWM channel has to be enabled first + * before writing to the registers. + */ + ret = clk_bulk_prepare_enable(SPRD_PWM_CHN_CLKS_NUM, + chn->clks); + if (ret) { + dev_err(spc->dev, + "failed to enable pwm%u clocks\n", + pwm->hwpwm); + return ret; + } + } + + if (state->period != cstate->period || + state->duty_cycle != cstate->duty_cycle) { + ret = sprd_pwm_config(spc, pwm, state->duty_cycle, + state->period); + if (ret) + return ret; + } + + sprd_pwm_write(spc, pwm->hwpwm, SPRD_PWM_ENABLE, 1); + } else if (cstate->enabled) { + /* + * Note: After setting SPRD_PWM_ENABLE to zero, the controller + * will not wait for current period to be completed, instead it + * will stop the PWM channel immediately. + */ + sprd_pwm_write(spc, pwm->hwpwm, SPRD_PWM_ENABLE, 0); + + clk_bulk_disable_unprepare(SPRD_PWM_CHN_CLKS_NUM, chn->clks); + } + + return 0; +} + +static const struct pwm_ops sprd_pwm_ops = { + .apply = sprd_pwm_apply, + .get_state = sprd_pwm_get_state, + .owner = THIS_MODULE, +}; + +static int sprd_pwm_clk_init(struct sprd_pwm_chip *spc) +{ + struct clk *clk_pwm; + int ret, i; + + for (i = 0; i < SPRD_PWM_CHN_NUM; i++) { + struct sprd_pwm_chn *chn = &spc->chn[i]; + int j; + + for (j = 0; j < SPRD_PWM_CHN_CLKS_NUM; ++j) + chn->clks[j].id = + sprd_pwm_clks[i * SPRD_PWM_CHN_CLKS_NUM + j]; + + ret = devm_clk_bulk_get(spc->dev, SPRD_PWM_CHN_CLKS_NUM, + chn->clks); + if (ret) { + if (ret == -ENOENT) + break; + + if (ret != -EPROBE_DEFER) + dev_err(spc->dev, + "failed to get channel clocks\n"); + + return ret; + } + + clk_pwm = chn->clks[SPRD_PWM_CHN_OUTPUT_CLK].clk; + chn->clk_rate = clk_get_rate(clk_pwm); + } + + if (!i) { + dev_err(spc->dev, "no available PWM channels\n"); + return -ENODEV; + } + + spc->num_pwms = i; + + return 0; +} + +static int sprd_pwm_probe(struct platform_device *pdev) +{ + struct sprd_pwm_chip *spc; + int ret; + + spc = devm_kzalloc(&pdev->dev, sizeof(*spc), GFP_KERNEL); + if (!spc) + return -ENOMEM; + + spc->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(spc->base)) + return PTR_ERR(spc->base); + + spc->dev = &pdev->dev; + platform_set_drvdata(pdev, spc); + + ret = sprd_pwm_clk_init(spc); + if (ret) + return ret; + + spc->chip.dev = &pdev->dev; + spc->chip.ops = &sprd_pwm_ops; + spc->chip.base = -1; + spc->chip.npwm = spc->num_pwms; + + ret = pwmchip_add(&spc->chip); + if (ret) + dev_err(&pdev->dev, "failed to add PWM chip\n"); + + return ret; +} + +static int sprd_pwm_remove(struct platform_device *pdev) +{ + struct sprd_pwm_chip *spc = platform_get_drvdata(pdev); + + return pwmchip_remove(&spc->chip); +} + +static const struct of_device_id sprd_pwm_of_match[] = { + { .compatible = "sprd,ums512-pwm", }, + { }, +}; +MODULE_DEVICE_TABLE(of, sprd_pwm_of_match); + +static struct platform_driver sprd_pwm_driver = { + .driver = { + .name = "sprd-pwm", + .of_match_table = sprd_pwm_of_match, + }, + .probe = sprd_pwm_probe, + .remove = sprd_pwm_remove, +}; + +module_platform_driver(sprd_pwm_driver); + +MODULE_DESCRIPTION("Spreadtrum PWM Driver"); +MODULE_LICENSE("GPL v2"); |