diff options
| author | Lukasz Majewski <lukma@denx.de> | 2017-01-29 22:54:11 +0100 |
|---|---|---|
| committer | Thierry Reding <thierry.reding@gmail.com> | 2017-01-30 09:12:52 +0100 |
| commit | 0ca1a11a1d816c8fb0bb29b985666cef912958c1 (patch) | |
| tree | 176d7786ae196e5d17198923bd50ac2d98245e06 /drivers | |
| parent | pwm: imx: Move PWMv2 wait for fifo slot code to a separate function (diff) | |
| download | linux-0ca1a11a1d816c8fb0bb29b985666cef912958c1.tar.xz linux-0ca1a11a1d816c8fb0bb29b985666cef912958c1.zip | |
pwm: imx: Provide atomic PWM support for i.MX PWMv2
This commit provides apply() callback implementation for i.MX's PWMv2.
Suggested-by: Stefan Agner <stefan@agner.ch>
Suggested-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Lukasz Majewski <l.majewski@majess.pl>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/pwm/pwm-imx.c | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-imx.c b/drivers/pwm/pwm-imx.c index d557279446ed..34f3031d5c40 100644 --- a/drivers/pwm/pwm-imx.c +++ b/drivers/pwm/pwm-imx.c @@ -248,6 +248,72 @@ static int imx_pwm_config(struct pwm_chip *chip, return ret; } +static int imx_pwm_apply_v2(struct pwm_chip *chip, struct pwm_device *pwm, + struct pwm_state *state) +{ + unsigned long period_cycles, duty_cycles, prescale; + struct imx_chip *imx = to_imx_chip(chip); + struct pwm_state cstate; + unsigned long long c; + int ret; + + pwm_get_state(pwm, &cstate); + + if (state->enabled) { + c = clk_get_rate(imx->clk_per); + c *= state->period; + + do_div(c, 1000000000); + period_cycles = c; + + prescale = period_cycles / 0x10000 + 1; + + period_cycles /= prescale; + c = (unsigned long long)period_cycles * state->duty_cycle; + do_div(c, state->period); + duty_cycles = c; + + /* + * according to imx pwm RM, the real period value should be + * PERIOD value in PWMPR plus 2. + */ + if (period_cycles > 2) + period_cycles -= 2; + else + period_cycles = 0; + + /* + * Wait for a free FIFO slot if the PWM is already enabled, and + * flush the FIFO if the PWM was disabled and is about to be + * enabled. + */ + if (cstate.enabled) { + imx_pwm_wait_fifo_slot(chip, pwm); + } else { + ret = clk_prepare_enable(imx->clk_per); + if (ret) + return ret; + + imx_pwm_sw_reset(chip); + } + + writel(duty_cycles, imx->mmio_base + MX3_PWMSAR); + writel(period_cycles, imx->mmio_base + MX3_PWMPR); + + writel(MX3_PWMCR_PRESCALER(prescale) | + MX3_PWMCR_DOZEEN | MX3_PWMCR_WAITEN | + MX3_PWMCR_DBGEN | MX3_PWMCR_CLKSRC_IPG_HIGH | + MX3_PWMCR_EN, + imx->mmio_base + MX3_PWMCR); + } else if (cstate.enabled) { + writel(0, imx->mmio_base + MX3_PWMCR); + + clk_disable_unprepare(imx->clk_per); + } + + return 0; +} + static int imx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) { struct imx_chip *imx = to_imx_chip(chip); @@ -279,6 +345,7 @@ static const struct pwm_ops imx_pwm_ops_v1 = { }; static const struct pwm_ops imx_pwm_ops_v2 = { + .apply = imx_pwm_apply_v2, .enable = imx_pwm_enable, .disable = imx_pwm_disable, .config = imx_pwm_config, |