[PATCH] iio: adc: stm32: add check on clock rate

From: Fabrice Gasnier
Date: Wed Oct 18 2017 - 07:41:17 EST


Add check on STM32 ADC clock rate to report an explicit error.
This may avoid division by 0 later in stm32-adc driver.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxx>
---
drivers/iio/adc/stm32-adc-core.c | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/drivers/iio/adc/stm32-adc-core.c b/drivers/iio/adc/stm32-adc-core.c
index 804198e..6aefef9 100644
--- a/drivers/iio/adc/stm32-adc-core.c
+++ b/drivers/iio/adc/stm32-adc-core.c
@@ -139,6 +139,11 @@ static int stm32f4_adc_clk_sel(struct platform_device *pdev,
}

rate = clk_get_rate(priv->aclk);
+ if (!rate) {
+ dev_err(&pdev->dev, "Invalid clock rate: 0\n");
+ return -EINVAL;
+ }
+
for (i = 0; i < ARRAY_SIZE(stm32f4_pclk_div); i++) {
if ((rate / stm32f4_pclk_div[i]) <= STM32F4_ADC_MAX_CLK_RATE)
break;
@@ -216,6 +221,10 @@ static int stm32h7_adc_clk_sel(struct platform_device *pdev,
* From spec: PLL output musn't exceed max rate
*/
rate = clk_get_rate(priv->aclk);
+ if (!rate) {
+ dev_err(&pdev->dev, "Invalid adc clock rate: 0\n");
+ return -EINVAL;
+ }

for (i = 0; i < ARRAY_SIZE(stm32h7_adc_ckmodes_spec); i++) {
ckmode = stm32h7_adc_ckmodes_spec[i].ckmode;
@@ -232,6 +241,10 @@ static int stm32h7_adc_clk_sel(struct platform_device *pdev,

/* Synchronous clock modes (e.g. ckmode is 1, 2 or 3) */
rate = clk_get_rate(priv->bclk);
+ if (!rate) {
+ dev_err(&pdev->dev, "Invalid bus clock rate: 0\n");
+ return -EINVAL;
+ }

for (i = 0; i < ARRAY_SIZE(stm32h7_adc_ckmodes_spec); i++) {
ckmode = stm32h7_adc_ckmodes_spec[i].ckmode;
--
1.9.1