[PATCH v2] pwm: add CSR SiRFSoC PWM driver
Barry Song
21cnbao at gmail.com
Thu Jan 30 00:52:25 EST 2014
From: Rongjun Ying <Rongjun.ying at csr.com>
PWM controller of CSR SiRFSoC can generate 7 independent outputs. Each output
duty cycle can be adjusted by setting the corresponding wait & hold registers.
Supports 7 independent channel output: 6 for external(channel0-5) and 1 for
internal(channel6).
Supports wide frequency range: divide by 2 to 65536*2 of source clock.
Signed-off-by: Rongjun Ying <Rongjun.ying at csr.com>
Signed-off-by: Huayi Li <Huayi.Li at csr.com>
Signed-off-by: Barry Song <Baohua.Song at csr.com>
---
-v2: clean the source clock of PWM wave, use OSC(26MHz)
drivers/pwm/Kconfig | 9 ++
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-sirf.c | 294 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 304 insertions(+), 0 deletions(-)
create mode 100644 drivers/pwm/pwm-sirf.c
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 7acab93..0a252f8 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -166,6 +166,15 @@ config PWM_SAMSUNG
To compile this driver as a module, choose M here: the module
will be called pwm-samsung.
+config PWM_SIRF
+ tristate "SiRF PWM support"
+ depends on ARCH_SIRF
+ help
+ Generic PWM framework driver for SiRF SoC.
+
+ To compile this driver as a module, choose M here: the module
+ will be called pwm-sirf.
+
config PWM_SPEAR
tristate "STMicroelectronics SPEAr PWM support"
depends on PLAT_SPEAR
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index 4abf337..49ab0d7 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_PWM_PUV3) += pwm-puv3.o
obj-$(CONFIG_PWM_PXA) += pwm-pxa.o
obj-$(CONFIG_PWM_RENESAS_TPU) += pwm-renesas-tpu.o
obj-$(CONFIG_PWM_SAMSUNG) += pwm-samsung.o
+obj-$(CONFIG_PWM_SIRF) += pwm-sirf.o
obj-$(CONFIG_PWM_SPEAR) += pwm-spear.o
obj-$(CONFIG_PWM_TEGRA) += pwm-tegra.o
obj-$(CONFIG_PWM_TIECAP) += pwm-tiecap.o
diff --git a/drivers/pwm/pwm-sirf.c b/drivers/pwm/pwm-sirf.c
new file mode 100644
index 0000000..1a5c5b7
--- /dev/null
+++ b/drivers/pwm/pwm-sirf.c
@@ -0,0 +1,294 @@
+/*
+ * SIRF serial SoC PWM device core driver
+ *
+ * Copyright (c) 2014 Cambridge Silicon Radio Limited, a CSR plc group company.
+ *
+ * Licensed under GPLv2 or later.
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/pwm.h>
+#include <linux/of.h>
+#include <linux/io.h>
+
+#define SIRF_PWM_SELECT_PRECLK 0x0
+#define SIRF_PWM_OE 0x4
+#define SIRF_PWM_ENABLE_PRECLOCK 0x8
+#define SIRF_PWM_ENABLE_POSTCLOCK 0xC
+#define SIRF_PWM_GET_WAIT_OFFSET(n) (0x10 + 0x8*n)
+#define SIRF_PWM_GET_HOLD_OFFSET(n) (0x14 + 0x8*n)
+
+#define SIRF_PWM_TR_STEP(n) (0x48 + 0x8*n)
+#define SIRF_PWM_STEP_HOLD(n) (0x4c + 0x8*n)
+
+#define SRC_FIELD_SIZE 3
+#define BYPASS_MODE_BIT 21
+#define TRANS_MODE_SELECT_BIT 7
+
+#define SIRF_PWM_CHL_NUM 7
+#define SIRF_PWM_BLS_GRP_NUM 16
+
+struct sirf_pwm {
+ void __iomem *base;
+ struct clk *clk;
+ struct pwm_chip chip;
+};
+
+#define to_sirf_chip(chip) container_of(chip, struct sirf_pwm, chip)
+
+static unsigned int sirf_pwm_ns_to_cycles(struct pwm_chip *chip, unsigned int time_ns)
+{
+ u64 dividend;
+ unsigned int cycle;
+ /*
+ * on SiRFSoC, OSC input is const, we use it as the source to generate
+ * PWM wave
+ */
+#define SRC_OSC_RATE 26000000ULL
+ dividend = SRC_OSC_RATE * time_ns + NSEC_PER_SEC / 2;
+ do_div(dividend, NSEC_PER_SEC);
+
+ cycle = dividend & 0xFFFFFFFFUL;
+
+ return cycle > 1 ? cycle : 1;
+}
+
+static int sirf_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+ int duty_ns, int period_ns)
+{
+ unsigned int period_cycles, high_cycles, low_cycles;
+ unsigned int val;
+ struct sirf_pwm *spwm = to_sirf_chip(chip);
+
+ period_cycles = sirf_pwm_ns_to_cycles(chip, period_ns);
+
+ high_cycles = sirf_pwm_ns_to_cycles(chip, duty_ns);
+ low_cycles = period_cycles - high_cycles;
+
+ if (period_cycles == 1) {
+ /* bypass mode */
+ val = readl(spwm->base + SIRF_PWM_SELECT_PRECLK);
+ val |= 0x1 << (BYPASS_MODE_BIT + pwm->hwpwm);
+ writel(val, spwm->base + SIRF_PWM_SELECT_PRECLK);
+ dev_warn(chip->dev, "period is too short!\n");
+ } else {
+ /* divider mode */
+ val = readl(spwm->base + SIRF_PWM_SELECT_PRECLK);
+ val &= ~(0x1 << (BYPASS_MODE_BIT + pwm->hwpwm));
+ writel(val, spwm->base + SIRF_PWM_SELECT_PRECLK);
+
+ if (high_cycles == period_cycles) {
+ high_cycles--;
+ low_cycles = 1;
+ }
+
+ writel(high_cycles, spwm->base + SIRF_PWM_GET_WAIT_OFFSET(pwm->hwpwm));
+ writel(low_cycles, spwm->base + SIRF_PWM_GET_HOLD_OFFSET(pwm->hwpwm));
+ }
+
+ return 0;
+}
+
+static int sirf_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct sirf_pwm *spwm = to_sirf_chip(chip);
+ unsigned int val;
+
+ /* disable preclock */
+ val = readl(spwm->base + SIRF_PWM_ENABLE_PRECLOCK);
+ val &= ~(1 << pwm->hwpwm);
+ writel(val, spwm->base + SIRF_PWM_ENABLE_PRECLOCK);
+
+ /* select preclock source must after disable preclk*/
+ val = readl(spwm->base + SIRF_PWM_SELECT_PRECLK);
+ val &= ~(0x7 << (SRC_FIELD_SIZE * pwm->hwpwm));
+ writel(val, spwm->base + SIRF_PWM_SELECT_PRECLK);
+ /* wait for some time */
+ udelay(100);
+
+ /* enable preclock */
+ val = readl(spwm->base + SIRF_PWM_ENABLE_PRECLOCK);
+ val |= (1 << pwm->hwpwm);
+ writel(val, spwm->base + SIRF_PWM_ENABLE_PRECLOCK);
+
+ /* enable post clock*/
+ val = readl(spwm->base + SIRF_PWM_ENABLE_POSTCLOCK);
+ val |= (1 << pwm->hwpwm);
+ writel(val, spwm->base + SIRF_PWM_ENABLE_POSTCLOCK);
+
+ /* enable output */
+ val = readl(spwm->base + SIRF_PWM_OE);
+ val |= 1 << pwm->hwpwm;
+ val &= ~(1 << (pwm->hwpwm + TRANS_MODE_SELECT_BIT));
+
+ writel(val, spwm->base + SIRF_PWM_OE);
+
+ return 0;
+}
+
+static void sirf_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ unsigned int val;
+ struct sirf_pwm *spwm = to_sirf_chip(chip);
+ /* disable output */
+ val = readl(spwm->base + SIRF_PWM_OE);
+ val &= ~(1 << pwm->hwpwm);
+ writel(val, spwm->base + SIRF_PWM_OE);
+
+ /* disable postclock */
+ val = readl(spwm->base + SIRF_PWM_ENABLE_POSTCLOCK);
+ val &= ~(1 << pwm->hwpwm);
+ writel(val, spwm->base + SIRF_PWM_ENABLE_POSTCLOCK);
+
+ /* disable preclock */
+ val = readl(spwm->base + SIRF_PWM_ENABLE_PRECLOCK);
+ val &= ~(1 << pwm->hwpwm);
+ writel(val, spwm->base + SIRF_PWM_ENABLE_PRECLOCK);
+}
+
+static struct pwm_ops sirf_pwm_ops = {
+ .enable = sirf_pwm_enable,
+ .disable = sirf_pwm_disable,
+ .config = sirf_pwm_config,
+ .owner = THIS_MODULE,
+};
+
+static int sirf_pwm_probe(struct platform_device *pdev)
+{
+ struct sirf_pwm *spwm;
+ struct resource *mem_res;
+ int ret;
+
+ spwm = devm_kzalloc(&pdev->dev, sizeof(struct sirf_pwm),
+ GFP_KERNEL);
+ if (!spwm)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, spwm);
+
+ mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ spwm->base = devm_ioremap_resource(&pdev->dev, mem_res);
+ if (!spwm->base)
+ return -ENOMEM;
+
+ spwm->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(spwm->clk)) {
+ dev_err(&pdev->dev, "Get clock failed.\n");
+ return PTR_ERR(spwm->clk);
+ }
+
+ clk_prepare_enable(spwm->clk);
+
+ spwm->chip.dev = &pdev->dev;
+ spwm->chip.ops = &sirf_pwm_ops;
+ spwm->chip.base = 0;
+ spwm->chip.npwm = SIRF_PWM_CHL_NUM;
+
+ ret = pwmchip_add(&spwm->chip);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to register pwm\n");
+ clk_disable_unprepare(spwm->clk);
+ return ret;
+ }
+
+ return 0;
+}
+
+static int sirf_pwm_remove(struct platform_device *pdev)
+{
+ struct sirf_pwm *spwm = platform_get_drvdata(pdev);
+ clk_disable_unprepare(spwm->clk);
+
+ pwmchip_remove(&spwm->chip);
+ return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int sirf_pwm_suspend(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct sirf_pwm *spwm = platform_get_drvdata(pdev);
+
+ clk_disable_unprepare(spwm->clk);
+
+ return 0;
+}
+
+static void sirf_pwm_config_restore(struct sirf_pwm *spwm)
+{
+ struct pwm_device *pwm;
+ int i;
+
+ for (i = 0; i < spwm->chip.npwm; i++) {
+ pwm = &spwm->chip.pwms[i];
+ /*
+ * while restoring from hibernation, state of pwm is enabled,
+ * but PWM hardware is not re-enabled
+ */
+ if (test_bit(PWMF_REQUESTED, &pwm->flags) &&
+ test_bit(PWMF_ENABLED, &pwm->flags))
+ sirf_pwm_enable(&spwm->chip, pwm);
+ }
+}
+
+static int sirf_pwm_resume(struct device *dev)
+{
+ struct sirf_pwm *spwm = dev_get_drvdata(dev);
+
+ clk_prepare_enable(spwm->clk);
+
+ sirf_pwm_config_restore(spwm);
+
+ return 0;
+}
+
+static int sirf_pwm_restore(struct device *dev)
+{
+ struct sirf_pwm *spwm = dev_get_drvdata(dev);
+
+ /* back from hibernation, clock is already enabled */
+ sirf_pwm_config_restore(spwm);
+
+ return 0;
+}
+
+#else
+#define sirf_pwm_resume NULL
+#define sirf_pwm_suspend NULL
+#define sirf_pwm_restore NULL
+#endif
+
+static const struct dev_pm_ops sirf_pwm_pm_ops = {
+ .suspend = sirf_pwm_suspend,
+ .resume = sirf_pwm_resume,
+ .restore = sirf_pwm_restore,
+};
+
+static const struct of_device_id sirf_pwm_of_match[] = {
+ { .compatible = "sirf,prima2-pwm", },
+ {}
+};
+MODULE_DEVICE_TABLE(of, sirf_pwm_of_match);
+
+static struct platform_driver sirf_pwm_driver = {
+ .driver = {
+ .name = "prima2-pwm",
+ .owner = THIS_MODULE,
+ .pm = &sirf_pwm_pm_ops,
+ .of_match_table = sirf_pwm_of_match,
+ },
+ .probe = sirf_pwm_probe,
+ .remove = sirf_pwm_remove,
+};
+
+module_platform_driver(sirf_pwm_driver);
+
+MODULE_DESCRIPTION("SIRF serial SoC PWM device core driver");
+MODULE_AUTHOR("RongJun Ying <Rongjun.Ying at csr.com>, "
+ "Huayi Li <huayi.li at csr.com>");
+MODULE_LICENSE("GPL v2");
--
1.7.5.4
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