Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751748Ab3HTIMm (ORCPT ); Tue, 20 Aug 2013 04:12:42 -0400 Received: from newsmtp5.atmel.com ([204.2.163.5]:10437 "EHLO sjogate2.atmel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751427Ab3HTIMj (ORCPT ); Tue, 20 Aug 2013 04:12:39 -0400 From: Bo Shen To: Thierry Reding Cc: plagnioj@jcrosoft.com, nicolas.ferre@atmel.com, linux-pwm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, Bo Shen Subject: [v2 PATCH] PWM: atmel-pwm: add PWM controller driver Date: Tue, 20 Aug 2013 16:11:55 +0800 Message-Id: <1376986316-10874-1-git-send-email-voice.shen@atmel.com> X-Mailer: git-send-email 1.7.9.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 11458 Lines: 420 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 --- This patch is based on the for-next branch on Linux pwm tree Test on at91sam9m10g45ek board with pwm led Test on sama5d31ek board with pwm backlight Changes in v2: - Address the comments from Thierry Reding .../devicetree/bindings/pwm/atmel-pwm.txt | 17 + drivers/pwm/Kconfig | 9 + drivers/pwm/Makefile | 1 + drivers/pwm/pwm-atmel.c | 328 ++++++++++++++++++++ 4 files changed, 355 insertions(+) create mode 100644 Documentation/devicetree/bindings/pwm/atmel-pwm.txt create mode 100644 drivers/pwm/pwm-atmel.c diff --git a/Documentation/devicetree/bindings/pwm/atmel-pwm.txt b/Documentation/devicetree/bindings/pwm/atmel-pwm.txt new file mode 100644 index 0000000..f7b04f7 --- /dev/null +++ b/Documentation/devicetree/bindings/pwm/atmel-pwm.txt @@ -0,0 +1,17 @@ +Atmel PWM controller + +Required properties: + - compatible: should be one of: + - "atmel,at91sam9rl-pwm" + - "atmel,sama5-pwm" + - reg: physical base address and length of the controller's registers + - #pwm-cells: Should be 3. See pwm.txt in this directory for a + description of the cells format + +Example: + + pwm0: pwm@f8034000 { + compatible = "atmel,at91sam9rl-pwm"; + reg = <0xf8034000 0x400>; + #pwm-cells = <3>; + }; diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index 75840b5..54237b9 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 77a8c18..5b193f8 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_IMX) += pwm-imx.o diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c new file mode 100644 index 0000000..a9af974 --- /dev/null +++ b/drivers/pwm/pwm-atmel.c @@ -0,0 +1,328 @@ +/* + * Driver for Atmel Pulse Width Modulation Controller + * + * Copyright (C) 2013 Atmel Semiconductor Technology Ltd. + * Bo Shen + * + * GPL v2 + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* 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_CMR 0x00 +/* 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 + +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(chip->base + offset); +} + +static inline void atmel_pwm_writel(struct atmel_pwm_chip *chip, + unsigned long offset, unsigned long val) +{ + writel(val, chip->base + offset); +} + +static inline u32 atmel_pwm_ch_readl(struct atmel_pwm_chip *chip, + unsigned int ch, unsigned long offset) +{ + return readl(chip->base + 0x200 + ch * 0x20 + offset); +} + +static inline void atmel_pwm_ch_writel(struct atmel_pwm_chip *chip, + unsigned int ch, unsigned long offset, + unsigned long val) +{ + writel(val, chip->base + 0x200 + ch * 0x20 + 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 long val, prd, dty, div, clk_rate; + int ret, pres = 0; + + clk_rate = clk_get_rate(atmel_pwm->clk); + + while (1) { + div = 1000000000; + div *= 1 << pres; + val = clk_rate * period_ns; + prd = div_u64(val, div); + val = clk_rate * duty_ns; + dty = div_u64(val, div); + + if (prd < 1 || dty < 0) + return -EINVAL; + + /* + * Although the period register is 32 bit, + * however the LSB 16 bits is used + */ + if (prd > 0xffff || dty > 0xffff) { + if (++pres > 16) + return -EINVAL; + continue; + } + + break; + } + + ret = clk_enable(atmel_pwm->clk); + if (ret) { + pr_err("failed to enable pwm clock\n"); + return ret; + } + + atmel_pwm->config(chip, pwm, dty, prd); + + /* Check whether need to disable clock */ + val = atmel_pwm_readl(atmel_pwm, PWM_SR); + if ((val & PWM_SR_ALL_CH_ON) == 0) + 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, only update the duty register + * + * When update duty value, it need 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 period update register to update + * value to period register, the same operation to duty register + */ + if (test_bit(PWMF_ENABLED, &pwm->flags)) { + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv2_CDTYUPD, dty); + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMv2_CPRDUPD, prd); + } 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; + + ret = clk_enable(atmel_pwm->clk); + if (ret) { + pr_err("failed to enable pwm clock\n"); + return ret; + } + + if (polarity == PWM_POLARITY_NORMAL) + val &= ~PWM_CMR_CPOL; + else + val |= PWM_CMR_CPOL; + + 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); + + clk_prepare_enable(atmel_pwm->clk); + + 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); + u32 val; + + atmel_pwm_writel(atmel_pwm, PWM_DIS, 1 << pwm->hwpwm); + + val = atmel_pwm_readl(atmel_pwm, PWM_SR); + if ((val & PWM_SR_ALL_CH_ON) == 0) + 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, +}; + +#ifdef CONFIG_OF +static const struct of_device_id atmel_pwm_dt_ids[] = { + { + .compatible = "atmel,at91sam9rl-pwm", + .data = &atmel_pwm_data_v1, + }, { + .compatible = "atmel,sama5-pwm", + .data = &atmel_pwm_data_v2, + }, { + /* sentinel */ + }, +}; +MODULE_DEVICE_TABLE(of, atmel_pwm_dt_ids); +#endif + +static int atmel_pwm_probe(struct platform_device *pdev) +{ + const struct of_device_id *of_id = + of_match_device(atmel_pwm_dt_ids, &pdev->dev); + 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; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) + return -ENODEV; + + atmel_pwm->base = devm_ioremap_resource(&pdev->dev, res); + + atmel_pwm->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(atmel_pwm->clk)) + return PTR_ERR(atmel_pwm->clk); + clk_prepare(atmel_pwm->clk); + + atmel_pwm->chip.dev = &pdev->dev; + atmel_pwm->chip.ops = &atmel_pwm_ops; + atmel_pwm->chip.of_xlate = of_pwm_xlate_with_flags; + atmel_pwm->chip.of_pwm_n_cells = 3; + atmel_pwm->chip.base = -1; + atmel_pwm->chip.npwm = 4; + + data = of_id->data; + 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); + return ret; + } + + platform_set_drvdata(pdev, atmel_pwm); + + return 0; +} + +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), + }, + .probe = atmel_pwm_probe, + .remove = atmel_pwm_remove, +}; +module_platform_driver(atmel_pwm_driver); + +MODULE_ALIAS("platform:atmel-pwm"); +MODULE_AUTHOR("Bo Shen "); +MODULE_DESCRIPTION("Atmel PWM driver"); +MODULE_LICENSE("GPL v2"); -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/