From: Praveen Kumar B <[email protected]> Add support for new version of pwm-cygnus. Add support to make PWM changes configured and stable.
Signed-off-by: Praveen Kumar B <[email protected]> Reviewed-by: Ray Jui <[email protected]> Reviewed-by: Scott Branden <[email protected]> Signed-off-by: Sheetal Tigadoli <[email protected]> --- drivers/pwm/pwm-bcm-kona.c | 95 ++++++++++++++++++++++++++++++++++++---------- 1 file changed, 76 insertions(+), 19 deletions(-) diff --git a/drivers/pwm/pwm-bcm-kona.c b/drivers/pwm/pwm-bcm-kona.c index fe63289..143843f 100644 --- a/drivers/pwm/pwm-bcm-kona.c +++ b/drivers/pwm/pwm-bcm-kona.c @@ -15,6 +15,7 @@ #include <linux/delay.h> #include <linux/err.h> #include <linux/io.h> +#include <linux/iopoll.h> #include <linux/ioport.h> #include <linux/math64.h> #include <linux/module.h> @@ -65,10 +66,19 @@ #define DUTY_CYCLE_HIGH_MIN (0x00000000) #define DUTY_CYCLE_HIGH_MAX (0x00ffffff) +#define PWM_MONITOR_OFFSET 0xb0 +#define PWM_MONITOR_TIMEOUT_US 5 + +enum kona_pwmc_ver { + KONA_PWM = 1, + CYGNUS_PWM +}; + struct kona_pwmc { struct pwm_chip chip; void __iomem *base; struct clk *clk; + enum kona_pwmc_ver version; }; static inline struct kona_pwmc *to_kona_pwmc(struct pwm_chip *_chip) @@ -76,10 +86,36 @@ static inline struct kona_pwmc *to_kona_pwmc(struct pwm_chip *_chip) return container_of(_chip, struct kona_pwmc, chip); } +static int kona_pwmc_wait_stable(struct pwm_chip *chip, unsigned int chan, + unsigned int kona_ver) +{ + struct kona_pwmc *kp = to_kona_pwmc(chip); + unsigned int value; + + switch (kona_ver) { + case KONA_PWM: + /* + * There must be a min 400ns delay between clearing trigger and + * settingit. Failing to do this may result in no PWM signal. + */ + ndelay(400); + return 0; + + case CYGNUS_PWM: + return readl_poll_timeout(kp->base + PWM_MONITOR_OFFSET, value, + !(value & (BIT(chan))), 0, + PWM_MONITOR_TIMEOUT_US); + + default: + return -ENODEV; + + } +} + /* * Clear trigger bit but set smooth bit to maintain old output. */ -static void kona_pwmc_prepare_for_settings(struct kona_pwmc *kp, +static int kona_pwmc_prepare_for_settings(struct kona_pwmc *kp, unsigned int chan) { unsigned int value = readl(kp->base + PWM_CONTROL_OFFSET); @@ -88,14 +124,10 @@ static void kona_pwmc_prepare_for_settings(struct kona_pwmc *kp, value &= ~(1 << PWM_CONTROL_TRIGGER_SHIFT(chan)); writel(value, kp->base + PWM_CONTROL_OFFSET); - /* - * There must be a min 400ns delay between clearing trigger and setting - * it. Failing to do this may result in no PWM signal. - */ - ndelay(400); + return kona_pwmc_wait_stable(&kp->chip, chan, kp->version); } -static void kona_pwmc_apply_settings(struct kona_pwmc *kp, unsigned int chan) +static int kona_pwmc_apply_settings(struct kona_pwmc *kp, unsigned int chan) { unsigned int value = readl(kp->base + PWM_CONTROL_OFFSET); @@ -104,8 +136,7 @@ static void kona_pwmc_apply_settings(struct kona_pwmc *kp, unsigned int chan) value |= 1 << PWM_CONTROL_TRIGGER_SHIFT(chan); writel(value, kp->base + PWM_CONTROL_OFFSET); - /* Trigger bit must be held high for at least 400 ns. */ - ndelay(400); + return kona_pwmc_wait_stable(&kp->chip, chan, kp->version); } static void kona_pwmc_disable(struct pwm_chip *chip, struct pwm_device *pwm) @@ -113,8 +144,13 @@ static void kona_pwmc_disable(struct pwm_chip *chip, struct pwm_device *pwm) struct kona_pwmc *kp = to_kona_pwmc(chip); unsigned int chan = pwm->hwpwm; unsigned int value; + int ret; - kona_pwmc_prepare_for_settings(kp, chan); + ret = kona_pwmc_prepare_for_settings(kp, chan); + if (ret < 0) { + dev_err(chip->dev, "failed to prepare pwm settings: %d\n", ret); + return; + } /* Simulate a disable by configuring for zero duty */ writel(0, kp->base + DUTY_CYCLE_HIGH_OFFSET(chan)); @@ -125,7 +161,11 @@ static void kona_pwmc_disable(struct pwm_chip *chip, struct pwm_device *pwm) value &= ~PRESCALE_MASK(chan); writel(value, kp->base + PRESCALE_OFFSET); - kona_pwmc_apply_settings(kp, chan); + ret = kona_pwmc_apply_settings(kp, chan); + if (ret < 0) { + dev_err(chip->dev, "failed to apply pwm settings: %d\n", ret); + return; + } clk_disable_unprepare(kp->clk); } @@ -188,7 +228,12 @@ static int kona_pwmc_apply(struct pwm_chip *chip, struct pwm_device *pwm, } } - kona_pwmc_prepare_for_settings(kp, chan); + ret = kona_pwmc_prepare_for_settings(kp, chan); + if (ret < 0) { + dev_err(chip->dev, + "failed to prepare pwm settings: %d\n", ret); + return ret; + } value = readl(kp->base + PRESCALE_OFFSET); value &= ~PRESCALE_MASK(chan); @@ -208,7 +253,12 @@ static int kona_pwmc_apply(struct pwm_chip *chip, struct pwm_device *pwm, writel(value, kp->base + PWM_CONTROL_OFFSET); } - kona_pwmc_apply_settings(kp, chan); + ret = kona_pwmc_apply_settings(kp, chan); + if (ret < 0) { + dev_err(chip->dev, + "failed to prepare pwm settings: %d\n", ret); + return ret; + } } else if (cstate.enabled) { kona_pwmc_disable(chip, pwm); } @@ -221,14 +271,26 @@ static int kona_pwmc_apply(struct pwm_chip *chip, struct pwm_device *pwm, .owner = THIS_MODULE, }; +static const struct of_device_id bcm_kona_pwmc_dt[] = { + { .compatible = "brcm,kona-pwm", .data = (void *)KONA_PWM}, + { .compatible = "brcm,cygnus-pwm", .data = (void *)CYGNUS_PWM}, + { }, +}; +MODULE_DEVICE_TABLE(of, bcm_kona_pwmc_dt); + static int kona_pwmc_probe(struct platform_device *pdev) { struct kona_pwmc *kp; struct resource *res; + const struct of_device_id *of_id; unsigned int chan; unsigned int value = 0; int ret = 0; + of_id = of_match_node(bcm_kona_pwmc_dt, pdev->dev.of_node); + if (!of_id) + return -ENODEV; + kp = devm_kzalloc(&pdev->dev, sizeof(*kp), GFP_KERNEL); if (kp == NULL) return -ENOMEM; @@ -241,6 +303,7 @@ static int kona_pwmc_probe(struct platform_device *pdev) kp->chip.npwm = 6; kp->chip.of_xlate = of_pwm_xlate_with_flags; kp->chip.of_pwm_n_cells = 3; + kp->version = (enum kona_pwmc_ver)of_id->data; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); kp->base = devm_ioremap_resource(&pdev->dev, res); @@ -287,12 +350,6 @@ static int kona_pwmc_remove(struct platform_device *pdev) return pwmchip_remove(&kp->chip); } -static const struct of_device_id bcm_kona_pwmc_dt[] = { - { .compatible = "brcm,kona-pwm" }, - { }, -}; -MODULE_DEVICE_TABLE(of, bcm_kona_pwmc_dt); - static struct platform_driver kona_pwmc_driver = { .driver = { .name = "bcm-kona-pwm", -- 1.9.1
