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pwm: imx: Move PWMv2 wait for fifo slot code to a separate function 

The code, which waits for fifo slot, has been extracted from
imx_pwm_config_v2 function and moved to new one - imx_pwm_wait_fifo_slot().

This change reduces the overall size of imx_pwm_config_v2() and prepares
it for atomic PWM operation.

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>
This commit is contained in:
Lukasz Majewski 2017-01-29 22:54:10 +01:00 committed by Thierry Reding
parent 970247a486
commit 73b1ff1f3e
1 changed files with 25 additions and 18 deletions
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41
drivers/pwm/pwm-imx.c
View File

@ -137,27 +137,15 @@ static void imx_pwm_sw_reset(struct pwm_chip *chip)
dev_warn(dev, "software reset timeout\n");
}
static int imx_pwm_config_v2(struct pwm_chip *chip,
struct pwm_device *pwm, int duty_ns, int period_ns)
static void imx_pwm_wait_fifo_slot(struct pwm_chip *chip,
struct pwm_device *pwm)
{
struct imx_chip *imx = to_imx_chip(chip);
struct device *dev = chip->dev;
unsigned long long c;
unsigned long period_cycles, duty_cycles, prescale;
unsigned int period_ms;
bool enable = pwm_is_enabled(pwm);
int fifoav;
u32 cr, sr;
u32 sr;
/*
* i.MX PWMv2 has a 4-word sample FIFO.
* In order to avoid FIFO overflow issue, we do software reset
* to clear all sample FIFO if the controller is disabled or
* wait for a full PWM cycle to get a relinquished FIFO slot
* when the controller is enabled and the FIFO is fully loaded.
*/
if (enable) {
sr = readl(imx->mmio_base + MX3_PWMSR);
fifoav = sr & MX3_PWMSR_FIFOAV_MASK;
if (fifoav == MX3_PWMSR_FIFOAV_4WORDS) {
@ -169,10 +157,29 @@ static int imx_pwm_config_v2(struct pwm_chip *chip,
if (fifoav == (sr & MX3_PWMSR_FIFOAV_MASK))
dev_warn(dev, "there is no free FIFO slot\n");
}
} else {
imx_pwm_sw_reset(chip);
}
static int imx_pwm_config_v2(struct pwm_chip *chip,
struct pwm_device *pwm, int duty_ns, int period_ns)
{
struct imx_chip *imx = to_imx_chip(chip);
unsigned long long c;
unsigned long period_cycles, duty_cycles, prescale;
bool enable = pwm_is_enabled(pwm);
u32 cr;
/*
* i.MX PWMv2 has a 4-word sample FIFO.
* In order to avoid FIFO overflow issue, we do software reset
* to clear all sample FIFO if the controller is disabled or
* wait for a full PWM cycle to get a relinquished FIFO slot
* when the controller is enabled and the FIFO is fully loaded.
*/
if (enable)
imx_pwm_wait_fifo_slot(chip, pwm);
else
imx_pwm_sw_reset(chip);
c = clk_get_rate(imx->clk_per);
c = c * period_ns;
do_div(c, 1000000000);