On 07/20/2012 09:31 AM, michael.hennerich@xxxxxxxxxx wrote:
> From: Michael Hennerich <michael.hennerich@xxxxxxxxxx>
>
> With small channel spacing values and high reference frequencies it is
> possible to exceed the range of the 10-bit counter.
> Workaround by checking the range and widening some constrains.
>
> We don't use the REG1_PHASE value in this case the datasheet recommends to set
> it to 1 if not used.
>
> Signed-off-by: Michael Hennerich <michael.hennerich@xxxxxxxxxx>
merged to fixes-togreg.
As an aside, I'm getting:
drivers/iio/frequency/adf4350.c: In function 'adf4350_read':
drivers/iio/frequency/adf4350.c:294:21: warning: 'val' may be used uninitialized in this function
Looks like a false positive, but might be worth cleaning up at some point...
Jonathan
> ---
> drivers/iio/frequency/adf4350.c | 24 +++++++++++++++---------
> include/linux/iio/frequency/adf4350.h | 2 ++
> 2 files changed, 17 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/iio/frequency/adf4350.c b/drivers/iio/frequency/adf4350.c
> index 59fbb3a..e35bb8f 100644
> --- a/drivers/iio/frequency/adf4350.c
> +++ b/drivers/iio/frequency/adf4350.c
> @@ -129,7 +129,7 @@ static int adf4350_set_freq(struct adf4350_state *st, unsigned long long freq)
> {
> struct adf4350_platform_data *pdata = st->pdata;
> u64 tmp;
> - u32 div_gcd, prescaler;
> + u32 div_gcd, prescaler, chspc;
> u16 mdiv, r_cnt = 0;
> u8 band_sel_div;
>
> @@ -158,14 +158,20 @@ static int adf4350_set_freq(struct adf4350_state *st, unsigned long long freq)
> if (pdata->ref_div_factor)
> r_cnt = pdata->ref_div_factor - 1;
>
> - do {
> - r_cnt = adf4350_tune_r_cnt(st, r_cnt);
> + chspc = st->chspc;
>
> - st->r1_mod = st->fpfd / st->chspc;
> - while (st->r1_mod > ADF4350_MAX_MODULUS) {
> - r_cnt = adf4350_tune_r_cnt(st, r_cnt);
> - st->r1_mod = st->fpfd / st->chspc;
> - }
> + do {
> + do {
> + do {
> + r_cnt = adf4350_tune_r_cnt(st, r_cnt);
> + st->r1_mod = st->fpfd / chspc;
> + if (r_cnt > ADF4350_MAX_R_CNT) {
> + /* try higher spacing values */
> + chspc++;
> + r_cnt = 0;
> + }
> + } while ((st->r1_mod > ADF4350_MAX_MODULUS) && r_cnt);
> + } while (r_cnt == 0);
>
> tmp = freq * (u64)st->r1_mod + (st->fpfd > 1);
> do_div(tmp, st->fpfd); /* Div round closest (n + d/2)/d */
> @@ -194,7 +200,7 @@ static int adf4350_set_freq(struct adf4350_state *st, unsigned long long freq)
> st->regs[ADF4350_REG0] = ADF4350_REG0_INT(st->r0_int) |
> ADF4350_REG0_FRACT(st->r0_fract);
>
> - st->regs[ADF4350_REG1] = ADF4350_REG1_PHASE(0) |
> + st->regs[ADF4350_REG1] = ADF4350_REG1_PHASE(1) |
> ADF4350_REG1_MOD(st->r1_mod) |
> prescaler;
>
> diff --git a/include/linux/iio/frequency/adf4350.h b/include/linux/iio/frequency/adf4350.h
> index b76b4a8..be91f34 100644
> --- a/include/linux/iio/frequency/adf4350.h
> +++ b/include/linux/iio/frequency/adf4350.h
> @@ -87,6 +87,8 @@
> #define ADF4350_MAX_BANDSEL_CLK 125000 /* Hz */
> #define ADF4350_MAX_FREQ_REFIN 250000000 /* Hz */
> #define ADF4350_MAX_MODULUS 4095
> +#define ADF4350_MAX_R_CNT 1023
> +
>
> /**
> * struct adf4350_platform_data - platform specific information
>
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