diff options
Diffstat (limited to 'drivers/pwm/pwm-jz4740.c')
| -rw-r--r-- | drivers/pwm/pwm-jz4740.c | 55 |
1 files changed, 39 insertions, 16 deletions
diff --git a/drivers/pwm/pwm-jz4740.c b/drivers/pwm/pwm-jz4740.c index 3cd5c054ad9a..5830ac2bdf6a 100644 --- a/drivers/pwm/pwm-jz4740.c +++ b/drivers/pwm/pwm-jz4740.c @@ -6,7 +6,6 @@ * Limitations: * - The .apply callback doesn't complete the currently running period before * reconfiguring the hardware. - * - Each period starts with the inactive part. */ #include <linux/clk.h> @@ -21,7 +20,9 @@ #include <linux/pwm.h> #include <linux/regmap.h> -#define NUM_PWM 8 +struct soc_info { + unsigned int num_pwms; +}; struct jz4740_pwm_chip { struct pwm_chip chip; @@ -37,7 +38,7 @@ static bool jz4740_pwm_can_use_chn(struct jz4740_pwm_chip *jz, unsigned int channel) { /* Enable all TCU channels for PWM use by default except channels 0/1 */ - u32 pwm_channels_mask = GENMASK(NUM_PWM - 1, 2); + u32 pwm_channels_mask = GENMASK(jz->chip.npwm - 1, 2); device_property_read_u32(jz->chip.dev->parent, "ingenic,pwm-channels-mask", @@ -158,12 +159,12 @@ static int jz4740_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, /* Calculate period value */ tmp = (unsigned long long)rate * state->period; do_div(tmp, NSEC_PER_SEC); - period = (unsigned long)tmp; + period = tmp; /* Calculate duty value */ - tmp = (unsigned long long)period * state->duty_cycle; - do_div(tmp, state->period); - duty = period - tmp; + tmp = (unsigned long long)rate * state->duty_cycle; + do_div(tmp, NSEC_PER_SEC); + duty = tmp; if (duty >= period) duty = period - 1; @@ -189,18 +190,26 @@ static int jz4740_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, regmap_update_bits(jz4740->map, TCU_REG_TCSRc(pwm->hwpwm), TCU_TCSR_PWM_SD, TCU_TCSR_PWM_SD); - /* Set polarity */ - switch (state->polarity) { - case PWM_POLARITY_NORMAL: + /* + * Set polarity. + * + * The PWM starts in inactive state until the internal timer reaches the + * duty value, then becomes active until the timer reaches the period + * value. In theory, we should then use (period - duty) as the real duty + * value, as a high duty value would otherwise result in the PWM pin + * being inactive most of the time. + * + * Here, we don't do that, and instead invert the polarity of the PWM + * when it is active. This trick makes the PWM start with its active + * state instead of its inactive state. + */ + if ((state->polarity == PWM_POLARITY_NORMAL) ^ state->enabled) regmap_update_bits(jz4740->map, TCU_REG_TCSRc(pwm->hwpwm), TCU_TCSR_PWM_INITL_HIGH, 0); - break; - case PWM_POLARITY_INVERSED: + else regmap_update_bits(jz4740->map, TCU_REG_TCSRc(pwm->hwpwm), TCU_TCSR_PWM_INITL_HIGH, TCU_TCSR_PWM_INITL_HIGH); - break; - } if (state->enabled) jz4740_pwm_enable(chip, pwm); @@ -219,6 +228,11 @@ static int jz4740_pwm_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct jz4740_pwm_chip *jz4740; + const struct soc_info *info; + + info = device_get_match_data(dev); + if (!info) + return -EINVAL; jz4740 = devm_kzalloc(dev, sizeof(*jz4740), GFP_KERNEL); if (!jz4740) @@ -232,7 +246,7 @@ static int jz4740_pwm_probe(struct platform_device *pdev) jz4740->chip.dev = dev; jz4740->chip.ops = &jz4740_pwm_ops; - jz4740->chip.npwm = NUM_PWM; + jz4740->chip.npwm = info->num_pwms; jz4740->chip.base = -1; jz4740->chip.of_xlate = of_pwm_xlate_with_flags; jz4740->chip.of_pwm_n_cells = 3; @@ -249,9 +263,18 @@ static int jz4740_pwm_remove(struct platform_device *pdev) return pwmchip_remove(&jz4740->chip); } +static const struct soc_info __maybe_unused jz4740_soc_info = { + .num_pwms = 8, +}; + +static const struct soc_info __maybe_unused jz4725b_soc_info = { + .num_pwms = 6, +}; + #ifdef CONFIG_OF static const struct of_device_id jz4740_pwm_dt_ids[] = { - { .compatible = "ingenic,jz4740-pwm", }, + { .compatible = "ingenic,jz4740-pwm", .data = &jz4740_soc_info }, + { .compatible = "ingenic,jz4725b-pwm", .data = &jz4725b_soc_info }, {}, }; MODULE_DEVICE_TABLE(of, jz4740_pwm_dt_ids); |