Messages in this thread |  | | Date | Mon, 2 Dec 2013 16:01:45 +0800 | From | Bo Shen <> | Subject | Re: [PATCH v8 1/2] PWM: atmel-pwm: add PWM controller driver |
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Hi Thierry,
On 11/18/2013 05:13 PM, Bo Shen wrote: > Add Atmel PWM controller driver based on PWM framework. > > This is the basic function implementation of Atmel PWM controller. > It can work with PWM based led and backlight. > > Signed-off-by: Bo Shen <voice.shen@atmel.com> > > Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> > Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> > --- > Changes in v8: > - replace pr_err by dev_err > > Changes in v7: > - fix issue for none device tree issues. > > Changes in v6: > - using relaxed version for writel and readl > - add none device tree support > - change some define from lower case to upper case > - split device tree binding document as a separate patch > > Changes in v5: > - call clk_disable directly, if so, it won't cause more than one channel > enabled, the clock can not be disabled. > > Changes in v4: > - check the return value of clk_prepare() > - change channel register size as constant > > Changes in v3: > - change compatible string from "atmel,sama5-pwm" to "atmel,sama5d3-pwm" > - Add PWM led example in binding documentation > - Using micro replace hard code > > Changes in v2: > - Address the comments from Thierry Reding > > drivers/pwm/Kconfig | 9 ++ > drivers/pwm/Makefile | 1 + > drivers/pwm/pwm-atmel.c | 380 +++++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 390 insertions(+) > create mode 100644 drivers/pwm/pwm-atmel.c
Any new comments on this patch series?
Best Regards, Bo Shen
> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig > index eece329..5043572 100644 > --- a/drivers/pwm/Kconfig > +++ b/drivers/pwm/Kconfig > @@ -41,6 +41,15 @@ config PWM_AB8500 > To compile this driver as a module, choose M here: the module > will be called pwm-ab8500. > > +config PWM_ATMEL > + tristate "Atmel PWM support" > + depends on ARCH_AT91 > + help > + Generic PWM framework driver for Atmel SoC. > + > + To compile this driver as a module, choose M here: the module > + will be called pwm-atmel. > + > config PWM_ATMEL_TCB > tristate "Atmel TC Block PWM support" > depends on ATMEL_TCLIB && OF > diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile > index 8b754e4..1b99cfb 100644 > --- a/drivers/pwm/Makefile > +++ b/drivers/pwm/Makefile > @@ -1,6 +1,7 @@ > obj-$(CONFIG_PWM) += core.o > obj-$(CONFIG_PWM_SYSFS) += sysfs.o > obj-$(CONFIG_PWM_AB8500) += pwm-ab8500.o > +obj-$(CONFIG_PWM_ATMEL) += pwm-atmel.o > obj-$(CONFIG_PWM_ATMEL_TCB) += pwm-atmel-tcb.o > obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o > obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o > diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c > new file mode 100644 > index 0000000..67cbac2 > --- /dev/null > +++ b/drivers/pwm/pwm-atmel.c > @@ -0,0 +1,380 @@ > +/* > + * Driver for Atmel Pulse Width Modulation Controller > + * > + * Copyright (C) 2013 Atmel Corporation > + * Bo Shen <voice.shen@atmel.com> > + * > + * Licensed under GPLv2. > + */ > + > +#include <linux/clk.h> > +#include <linux/err.h> > +#include <linux/io.h> > +#include <linux/module.h> > +#include <linux/of.h> > +#include <linux/of_device.h> > +#include <linux/platform_device.h> > +#include <linux/pwm.h> > +#include <linux/slab.h> > + > +/* The following is global registers for PWM controller */ > +#define PWM_ENA 0x04 > +#define PWM_DIS 0x08 > +#define PWM_SR 0x0C > +/* Bit field in SR */ > +#define PWM_SR_ALL_CH_ON 0x0F > + > +/* The following register is PWM channel related registers */ > +#define PWM_CH_REG_OFFSET 0x200 > +#define PWM_CH_REG_SIZE 0x20 > + > +#define PWM_CMR 0x0 > +/* Bit field in CMR */ > +#define PWM_CMR_CPOL (1 << 9) > +#define PWM_CMR_UPD_CDTY (1 << 10) > + > +/* The following registers for PWM v1 */ > +#define PWMV1_CDTY 0x04 > +#define PWMV1_CPRD 0x08 > +#define PWMV1_CUPD 0x10 > + > +/* The following registers for PWM v2 */ > +#define PWMV2_CDTY 0x04 > +#define PWMV2_CDTYUPD 0x08 > +#define PWMV2_CPRD 0x0C > +#define PWMV2_CPRDUPD 0x10 > + > +/* Max value for duty and period > + * > + * Although the duty and period register is 32 bit, > + * however only the LSB 16 bits are significant. > + */ > +#define PWM_MAX_DTY 0xFFFF > +#define PWM_MAX_PRD 0xFFFF > +#define PRD_MAX_PRES 10 > + > +struct atmel_pwm_chip { > + struct pwm_chip chip; > + struct clk *clk; > + void __iomem *base; > + > + void (*config)(struct pwm_chip *chip, struct pwm_device *pwm, > + int dty, int prd); > +}; > + > +static inline struct atmel_pwm_chip *to_atmel_pwm_chip(struct pwm_chip *chip) > +{ > + return container_of(chip, struct atmel_pwm_chip, chip); > +} > + > +static inline u32 atmel_pwm_readl(struct atmel_pwm_chip *chip, > + unsigned long offset) > +{ > + return readl_relaxed(chip->base + offset); > +} > + > +static inline void atmel_pwm_writel(struct atmel_pwm_chip *chip, > + unsigned long offset, unsigned long val) > +{ > + writel_relaxed(val, chip->base + offset); > +} > + > +static inline u32 atmel_pwm_ch_readl(struct atmel_pwm_chip *chip, > + unsigned int ch, unsigned long offset) > +{ > + return readl_relaxed(chip->base + PWM_CH_REG_OFFSET + > + ch * PWM_CH_REG_SIZE + offset); > +} > + > +static inline void atmel_pwm_ch_writel(struct atmel_pwm_chip *chip, > + unsigned int ch, unsigned long offset, > + unsigned long val) > +{ > + writel_relaxed(val, chip->base + PWM_CH_REG_OFFSET + > + ch * PWM_CH_REG_SIZE + offset); > +} > + > +static int atmel_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, > + int duty_ns, int period_ns) > +{ > + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip); > + unsigned long clk_rate, prd, dty; > + unsigned long long div; > + int ret, pres = 0; > + > + clk_rate = clk_get_rate(atmel_pwm->clk); > + div = clk_rate; > + > + /* Calculate the period cycles */ > + while (div > PWM_MAX_PRD) { > + div = clk_rate / (1 << pres); > + div = div * period_ns; > + /* 1/Hz = 100000000 ns */ > + do_div(div, 1000000000); > + > + if (pres++ > PRD_MAX_PRES) { > + dev_err(chip->dev, "pres exceed the maximum value\n"); > + return -EINVAL; > + } > + } > + > + /* Calculate the duty cycles */ > + prd = div; > + div *= duty_ns; > + do_div(div, period_ns); > + dty = div; > + > + ret = clk_enable(atmel_pwm->clk); > + if (ret) { > + dev_err(chip->dev, "failed to enable pwm clock\n"); > + return ret; > + } > + > + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, pres); > + atmel_pwm->config(chip, pwm, dty, prd); > + > + clk_disable(atmel_pwm->clk); > + > + return 0; > +} > + > +static void atmel_pwm_config_v1(struct pwm_chip *chip, struct pwm_device *pwm, > + int dty, int prd) > +{ > + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip); > + unsigned int val; > + > + /* > + * If the PWM channel is disabled, write value to duty and period > + * registers directly. > + * If the PWM channel is enabled, using the update register, it needs > + * to set bit 10 of CMR to 0 > + */ > + if (test_bit(PWMF_ENABLED, &pwm->flags)) { > + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CUPD, dty); > + > + val = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm, PWM_CMR); > + val &= ~PWM_CMR_UPD_CDTY; > + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val); > + } else { > + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CDTY, dty); > + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CPRD, prd); > + } > +} > + > +static void atmel_pwm_config_v2(struct pwm_chip *chip, struct pwm_device *pwm, > + int dty, int prd) > +{ > + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip); > + > + /* > + * If the PWM channel is disabled, write value to duty and period > + * registers directly. > + * If the PWM channel is enabled, using the duty update register to > + * update the value. > + */ > + if (test_bit(PWMF_ENABLED, &pwm->flags)) { > + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV2_CDTYUPD, dty); > + } else { > + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV2_CDTY, dty); > + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV2_CPRD, prd); > + } > +} > + > +static int atmel_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm, > + enum pwm_polarity polarity) > +{ > + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip); > + u32 val = 0; > + int ret; > + > + if (polarity == PWM_POLARITY_NORMAL) > + val &= ~PWM_CMR_CPOL; > + else > + val |= PWM_CMR_CPOL; > + > + ret = clk_enable(atmel_pwm->clk); > + if (ret) { > + dev_err(chip->dev, "failed to enable pwm clock\n"); > + return ret; > + } > + > + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val); > + > + clk_disable(atmel_pwm->clk); > + > + return 0; > +} > + > +static int atmel_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) > +{ > + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip); > + int ret; > + > + ret = clk_enable(atmel_pwm->clk); > + if (ret) { > + dev_err(chip->dev, "failed to enable pwm clock\n"); > + return ret; > + } > + > + atmel_pwm_writel(atmel_pwm, PWM_ENA, 1 << pwm->hwpwm); > + > + return 0; > +} > + > +static void atmel_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) > +{ > + struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip); > + > + atmel_pwm_writel(atmel_pwm, PWM_DIS, 1 << pwm->hwpwm); > + > + clk_disable(atmel_pwm->clk); > +} > + > +static const struct pwm_ops atmel_pwm_ops = { > + .config = atmel_pwm_config, > + .set_polarity = atmel_pwm_set_polarity, > + .enable = atmel_pwm_enable, > + .disable = atmel_pwm_disable, > + .owner = THIS_MODULE, > +}; > + > +struct atmel_pwm_data { > + void (*config)(struct pwm_chip *chip, struct pwm_device *pwm, > + int dty, int prd); > +}; > + > +static const struct atmel_pwm_data atmel_pwm_data_v1 = { > + .config = atmel_pwm_config_v1, > +}; > + > +static const struct atmel_pwm_data atmel_pwm_data_v2 = { > + .config = atmel_pwm_config_v2, > +}; > + > +static const struct platform_device_id atmel_pwm_devtypes[] = { > + { > + .name = "at91sam9rl-pwm", > + .driver_data = (kernel_ulong_t)&atmel_pwm_data_v1, > + }, { > + .name = "sama5d3-pwm", > + .driver_data = (kernel_ulong_t)&atmel_pwm_data_v2, > + }, { > + /* sentinel */ > + }, > +}; > +MODULE_DEVICE_TABLE(platform, atmel_pwm_devtypes); > + > +#ifdef CONFIG_OF > +static const struct of_device_id atmel_pwm_dt_ids[] = { > + { > + .compatible = "atmel,at91sam9rl-pwm", > + .data = &atmel_pwm_data_v1, > + }, { > + .compatible = "atmel,sama5d3-pwm", > + .data = &atmel_pwm_data_v2, > + }, { > + /* sentinel */ > + }, > +}; > +MODULE_DEVICE_TABLE(of, atmel_pwm_dt_ids); > +#endif > + > +static inline const struct atmel_pwm_data * __init > + atmel_pwm_get_driver_data(struct platform_device *pdev) > +{ > + if (pdev->dev.of_node) { > + const struct of_device_id *match; > + match = of_match_device(atmel_pwm_dt_ids, &pdev->dev); > + if (match == NULL) > + return NULL; > + return match->data; > + } > + > + return (struct atmel_pwm_data *) > + platform_get_device_id(pdev)->driver_data; > +} > + > +static int atmel_pwm_probe(struct platform_device *pdev) > +{ > + const struct atmel_pwm_data *data; > + struct atmel_pwm_chip *atmel_pwm; > + struct resource *res; > + int ret; > + > + atmel_pwm = devm_kzalloc(&pdev->dev, sizeof(*atmel_pwm), GFP_KERNEL); > + if (!atmel_pwm) > + return -ENOMEM; > + > + data = atmel_pwm_get_driver_data(pdev); > + if (!data) > + return -ENODEV; > + > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + if (!res) > + return -ENODEV; > + > + atmel_pwm->base = devm_ioremap_resource(&pdev->dev, res); > + if (IS_ERR(atmel_pwm->base)) > + return PTR_ERR(atmel_pwm->base); > + > + atmel_pwm->clk = devm_clk_get(&pdev->dev, NULL); > + if (IS_ERR(atmel_pwm->clk)) > + return PTR_ERR(atmel_pwm->clk); > + > + ret = clk_prepare(atmel_pwm->clk); > + if (ret) { > + dev_err(&pdev->dev, "failed to prepare pwm clock\n"); > + return ret; > + } > + > + atmel_pwm->chip.dev = &pdev->dev; > + atmel_pwm->chip.ops = &atmel_pwm_ops; > + if (pdev->dev.of_node) { > + atmel_pwm->chip.of_xlate = of_pwm_xlate_with_flags; > + atmel_pwm->chip.of_pwm_n_cells = 3; > + atmel_pwm->chip.base = -1; > + } else { > + atmel_pwm->chip.base = pdev->id; > + } > + atmel_pwm->chip.npwm = 4; > + > + atmel_pwm->config = data->config; > + > + ret = pwmchip_add(&atmel_pwm->chip); > + if (ret < 0) { > + dev_err(&pdev->dev, "failed to add pwm chip %d\n", ret); > + goto unprepare_clk; > + } > + > + platform_set_drvdata(pdev, atmel_pwm); > + > +unprepare_clk: > + clk_unprepare(atmel_pwm->clk); > + return ret; > +} > + > +static int atmel_pwm_remove(struct platform_device *pdev) > +{ > + struct atmel_pwm_chip *atmel_pwm = platform_get_drvdata(pdev); > + > + clk_unprepare(atmel_pwm->clk); > + > + return pwmchip_remove(&atmel_pwm->chip); > +} > + > +static struct platform_driver atmel_pwm_driver = { > + .driver = { > + .name = "atmel-pwm", > + .of_match_table = of_match_ptr(atmel_pwm_dt_ids), > + }, > + .id_table = atmel_pwm_devtypes, > + .probe = atmel_pwm_probe, > + .remove = atmel_pwm_remove, > +}; > +module_platform_driver(atmel_pwm_driver); > + > +MODULE_ALIAS("platform:atmel-pwm"); > +MODULE_AUTHOR("Bo Shen <voice.shen@atmel.com>"); > +MODULE_DESCRIPTION("Atmel PWM driver"); > +MODULE_LICENSE("GPL v2"); >
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