zl3073x_pin_props_get() always adds the current pin frequency to the supported list without checking it. A sub-Hz frequency reads back as 0 Hz, so 0 Hz can then be requested and the output frequency set callback divides by zero. A 0 Hz entry in the firmware node is not rejected either: it is offered for an input pin, and for an output pin zl3073x_pin_check_freq() divides by it at probe time. Do not add a 0 Hz current frequency and reject 0 Hz in zl3073x_pin_check_freq(). If the list ends up empty, do not publish it at all, as the DPLL core rejects an empty non-NULL list. Found by code inspection, not triggered at runtime. Fixes: 85a9aaac4a38 ("dpll: zl3073x: Include current frequency in supported frequencies list") Reviewed-by: Petr Oros Signed-off-by: Ivan Vecera --- drivers/dpll/zl3073x/prop.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) diff --git a/drivers/dpll/zl3073x/prop.c b/drivers/dpll/zl3073x/prop.c index ac9d41d0f978..768e5424de2d 100644 --- a/drivers/dpll/zl3073x/prop.c +++ b/drivers/dpll/zl3073x/prop.c @@ -30,7 +30,7 @@ static bool zl3073x_pin_check_freq(struct zl3073x_dev *zldev, enum dpll_pin_direction dir, u8 id, u64 freq) { - if (freq > U32_MAX) + if (!freq || freq > U32_MAX) goto err_inv_freq; if (dir == DPLL_PIN_DIRECTION_INPUT) { @@ -295,13 +295,20 @@ struct zl3073x_pin_props *zl3073x_pin_props_get(struct zl3073x_dev *zldev, goto err_alloc_ranges; } - /* Start with current frequency at index 0 */ - ranges[0] = (struct dpll_pin_frequency)DPLL_PIN_FREQUENCY(curr_freq); + /* Start with current frequency at index 0. A sub-Hz frequency is + * read back as 0 Hz and cannot be set, so it is not offered. + */ + j = 0; + if (curr_freq) { + struct dpll_pin_frequency freq = DPLL_PIN_FREQUENCY(curr_freq); + + ranges[j++] = freq; + } /* Add frequencies from firmware node, skipping current frequency * and filtering out frequencies not representable by device */ - for (i = 0, j = 1; i < num_freqs; i++) { + for (i = 0; i < num_freqs; i++) { struct dpll_pin_frequency freq = DPLL_PIN_FREQUENCY(freqs[i]); if (freqs[i] == curr_freq) @@ -312,6 +319,14 @@ struct zl3073x_pin_props *zl3073x_pin_props_get(struct zl3073x_dev *zldev, } } + /* The DPLL core rejects a non-NULL list without entries, so do + * not publish the array at all when nothing is settable. + */ + if (!j) { + kfree(ranges); + ranges = NULL; + } + /* Save number of freq ranges and pointer to them into pin properties */ props->dpll_props.freq_supported = ranges; props->dpll_props.freq_supported_num = j; -- 2.56.0