From 4836193c435c95443fdebb6b9d4a58032999dbb3 Mon Sep 17 00:00:00 2001 From: Shawn Guo Date: Thu, 27 Jul 2017 16:23:37 +0800 Subject: [PATCH] pwm: Add ZTE ZX PWM device driver It adds PWM device driver for ZTE ZX family SoCs. The PWM controller supports 4 devices with polarity configuration. The driver has been tested with pwm-regulator support to scale core voltage via cpufreq. Signed-off-by: Shawn Guo Signed-off-by: Thierry Reding --- drivers/pwm/Kconfig | 9 ++ drivers/pwm/Makefile | 1 + drivers/pwm/pwm-zx.c | 282 +++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 292 insertions(+) create mode 100644 drivers/pwm/pwm-zx.c diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index 313c10789ca2..e98175331a69 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -500,4 +500,13 @@ config PWM_VT8500 To compile this driver as a module, choose M here: the module will be called pwm-vt8500. +config PWM_ZX + tristate "ZTE ZX PWM support" + depends on ARCH_ZX + help + Generic PWM framework driver for ZTE ZX family SoCs. + + To compile this driver as a module, choose M here: the module + will be called pwm-zx. + endif diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index 93da1f79a3b8..75ab74094d7b 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -49,3 +49,4 @@ obj-$(CONFIG_PWM_TIPWMSS) += pwm-tipwmss.o obj-$(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_ZX) += pwm-zx.o diff --git a/drivers/pwm/pwm-zx.c b/drivers/pwm/pwm-zx.c new file mode 100644 index 000000000000..5d27c16edfb1 --- /dev/null +++ b/drivers/pwm/pwm-zx.c @@ -0,0 +1,282 @@ +/* + * Copyright (C) 2017 Sanechips Technology Co., Ltd. + * Copyright 2017 Linaro Ltd. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#define ZX_PWM_MODE 0x0 +#define ZX_PWM_CLKDIV_SHIFT 2 +#define ZX_PWM_CLKDIV_MASK GENMASK(11, 2) +#define ZX_PWM_CLKDIV(x) (((x) << ZX_PWM_CLKDIV_SHIFT) & \ + ZX_PWM_CLKDIV_MASK) +#define ZX_PWM_POLAR BIT(1) +#define ZX_PWM_EN BIT(0) +#define ZX_PWM_PERIOD 0x4 +#define ZX_PWM_DUTY 0x8 + +#define ZX_PWM_CLKDIV_MAX 1023 +#define ZX_PWM_PERIOD_MAX 65535 + +struct zx_pwm_chip { + struct pwm_chip chip; + struct clk *pclk; + struct clk *wclk; + void __iomem *base; +}; + +static inline struct zx_pwm_chip *to_zx_pwm_chip(struct pwm_chip *chip) +{ + return container_of(chip, struct zx_pwm_chip, chip); +} + +static inline u32 zx_pwm_readl(struct zx_pwm_chip *zpc, unsigned int hwpwm, + unsigned int offset) +{ + return readl(zpc->base + (hwpwm + 1) * 0x10 + offset); +} + +static inline void zx_pwm_writel(struct zx_pwm_chip *zpc, unsigned int hwpwm, + unsigned int offset, u32 value) +{ + writel(value, zpc->base + (hwpwm + 1) * 0x10 + offset); +} + +static void zx_pwm_set_mask(struct zx_pwm_chip *zpc, unsigned int hwpwm, + unsigned int offset, u32 mask, u32 value) +{ + u32 data; + + data = zx_pwm_readl(zpc, hwpwm, offset); + data &= ~mask; + data |= value & mask; + zx_pwm_writel(zpc, hwpwm, offset, data); +} + +static void zx_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm, + struct pwm_state *state) +{ + struct zx_pwm_chip *zpc = to_zx_pwm_chip(chip); + unsigned long rate; + unsigned int div; + u32 value; + u64 tmp; + + value = zx_pwm_readl(zpc, pwm->hwpwm, ZX_PWM_MODE); + + if (value & ZX_PWM_POLAR) + state->polarity = PWM_POLARITY_NORMAL; + else + state->polarity = PWM_POLARITY_INVERSED; + + if (value & ZX_PWM_EN) + state->enabled = true; + else + state->enabled = false; + + div = (value & ZX_PWM_CLKDIV_MASK) >> ZX_PWM_CLKDIV_SHIFT; + rate = clk_get_rate(zpc->wclk); + + tmp = zx_pwm_readl(zpc, pwm->hwpwm, ZX_PWM_PERIOD); + tmp *= div * NSEC_PER_SEC; + state->period = DIV_ROUND_CLOSEST_ULL(tmp, rate); + + tmp = zx_pwm_readl(zpc, pwm->hwpwm, ZX_PWM_DUTY); + tmp *= div * NSEC_PER_SEC; + state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, rate); +} + +static int zx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, + unsigned int duty_ns, unsigned int period_ns) +{ + struct zx_pwm_chip *zpc = to_zx_pwm_chip(chip); + unsigned int period_cycles, duty_cycles; + unsigned long long c; + unsigned int div = 1; + unsigned long rate; + + /* Find out the best divider */ + rate = clk_get_rate(zpc->wclk); + + while (1) { + c = rate / div; + c = c * period_ns; + do_div(c, NSEC_PER_SEC); + + if (c < ZX_PWM_PERIOD_MAX) + break; + + div++; + + if (div > ZX_PWM_CLKDIV_MAX) + return -ERANGE; + } + + /* Calculate duty cycles */ + period_cycles = c; + c *= duty_ns; + do_div(c, period_ns); + duty_cycles = c; + + /* + * If the PWM is being enabled, we have to temporarily disable it + * before configuring the registers. + */ + if (pwm_is_enabled(pwm)) + zx_pwm_set_mask(zpc, pwm->hwpwm, ZX_PWM_MODE, ZX_PWM_EN, 0); + + /* Set up registers */ + zx_pwm_set_mask(zpc, pwm->hwpwm, ZX_PWM_MODE, ZX_PWM_CLKDIV_MASK, + ZX_PWM_CLKDIV(div)); + zx_pwm_writel(zpc, pwm->hwpwm, ZX_PWM_PERIOD, period_cycles); + zx_pwm_writel(zpc, pwm->hwpwm, ZX_PWM_DUTY, duty_cycles); + + /* Re-enable the PWM if needed */ + if (pwm_is_enabled(pwm)) + zx_pwm_set_mask(zpc, pwm->hwpwm, ZX_PWM_MODE, + ZX_PWM_EN, ZX_PWM_EN); + + return 0; +} + +static int zx_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, + struct pwm_state *state) +{ + struct zx_pwm_chip *zpc = to_zx_pwm_chip(chip); + struct pwm_state cstate; + int ret; + + pwm_get_state(pwm, &cstate); + + if (state->polarity != cstate.polarity) + zx_pwm_set_mask(zpc, pwm->hwpwm, ZX_PWM_MODE, ZX_PWM_POLAR, + (state->polarity == PWM_POLARITY_INVERSED) ? + 0 : ZX_PWM_POLAR); + + if (state->period != cstate.period || + state->duty_cycle != cstate.duty_cycle) { + ret = zx_pwm_config(chip, pwm, state->duty_cycle, + state->period); + if (ret) + return ret; + } + + if (state->enabled != cstate.enabled) { + if (state->enabled) { + ret = clk_prepare_enable(zpc->wclk); + if (ret) + return ret; + + zx_pwm_set_mask(zpc, pwm->hwpwm, ZX_PWM_MODE, + ZX_PWM_EN, ZX_PWM_EN); + } else { + zx_pwm_set_mask(zpc, pwm->hwpwm, ZX_PWM_MODE, + ZX_PWM_EN, 0); + clk_disable_unprepare(zpc->wclk); + } + } + + return 0; +} + +static const struct pwm_ops zx_pwm_ops = { + .apply = zx_pwm_apply, + .get_state = zx_pwm_get_state, + .owner = THIS_MODULE, +}; + +static int zx_pwm_probe(struct platform_device *pdev) +{ + struct zx_pwm_chip *zpc; + struct resource *res; + unsigned int i; + int ret; + + zpc = devm_kzalloc(&pdev->dev, sizeof(*zpc), GFP_KERNEL); + if (!zpc) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + zpc->base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(zpc->base)) + return PTR_ERR(zpc->base); + + zpc->pclk = devm_clk_get(&pdev->dev, "pclk"); + if (IS_ERR(zpc->pclk)) + return PTR_ERR(zpc->pclk); + + zpc->wclk = devm_clk_get(&pdev->dev, "wclk"); + if (IS_ERR(zpc->wclk)) + return PTR_ERR(zpc->wclk); + + ret = clk_prepare_enable(zpc->pclk); + if (ret) + return ret; + + zpc->chip.dev = &pdev->dev; + zpc->chip.ops = &zx_pwm_ops; + zpc->chip.base = -1; + zpc->chip.npwm = 4; + zpc->chip.of_xlate = of_pwm_xlate_with_flags; + zpc->chip.of_pwm_n_cells = 3; + + /* + * PWM devices may be enabled by firmware, and let's disable all of + * them initially to save power. + */ + for (i = 0; i < zpc->chip.npwm; i++) + zx_pwm_set_mask(zpc, i, ZX_PWM_MODE, ZX_PWM_EN, 0); + + ret = pwmchip_add(&zpc->chip); + if (ret < 0) { + dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret); + return ret; + } + + platform_set_drvdata(pdev, zpc); + + return 0; +} + +static int zx_pwm_remove(struct platform_device *pdev) +{ + struct zx_pwm_chip *zpc = platform_get_drvdata(pdev); + int ret; + + ret = pwmchip_remove(&zpc->chip); + clk_disable_unprepare(zpc->pclk); + + return ret; +} + +static const struct of_device_id zx_pwm_dt_ids[] = { + { .compatible = "zte,zx296718-pwm", }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, zx_pwm_dt_ids); + +static struct platform_driver zx_pwm_driver = { + .driver = { + .name = "zx-pwm", + .of_match_table = zx_pwm_dt_ids, + }, + .probe = zx_pwm_probe, + .remove = zx_pwm_remove, +}; +module_platform_driver(zx_pwm_driver); + +MODULE_ALIAS("platform:zx-pwm"); +MODULE_AUTHOR("Shawn Guo "); +MODULE_DESCRIPTION("ZTE ZX PWM Driver"); +MODULE_LICENSE("GPL v2");