diff options
| author | Fabrice Gasnier <fabrice.gasnier@st.com> | 2019-10-28 19:11:48 +0300 |
|---|---|---|
| committer | Jonathan Cameron <Jonathan.Cameron@huawei.com> | 2019-11-09 15:37:18 +0300 |
| commit | cb7e1b50e4e382c2c63ac0c80260db55c3a3c7ee (patch) | |
| tree | da91626900d5f527319900ed52f8f68ebd92e989 /drivers/iio | |
| parent | a1acbc223a0c000edc5353f0710d0001772c158d (diff) | |
| download | linux-cb7e1b50e4e382c2c63ac0c80260db55c3a3c7ee.tar.xz | |
iio: adc: stm32: allow to tune analog clock
Add new optional dt property to tune analog clock prescaler.
Driver looks for optional "st,max-clk-rate-hz", then computes
best approximation below that rate, using ADC internal prescaler.
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Diffstat (limited to 'drivers/iio')
| -rw-r--r-- | drivers/iio/adc/stm32-adc-core.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/drivers/iio/adc/stm32-adc-core.c b/drivers/iio/adc/stm32-adc-core.c index 20c626c289ed..6537f4f776c5 100644 --- a/drivers/iio/adc/stm32-adc-core.c +++ b/drivers/iio/adc/stm32-adc-core.c @@ -79,6 +79,7 @@ struct stm32_adc_priv_cfg { * @domain: irq domain reference * @aclk: clock reference for the analog circuitry * @bclk: bus clock common for all ADCs, depends on part used + * @max_clk_rate: desired maximum clock rate * @booster: booster supply reference * @vdd: vdd supply reference * @vdda: vdda analog supply reference @@ -95,6 +96,7 @@ struct stm32_adc_priv { struct irq_domain *domain; struct clk *aclk; struct clk *bclk; + u32 max_clk_rate; struct regulator *booster; struct regulator *vdd; struct regulator *vdda; @@ -141,7 +143,7 @@ static int stm32f4_adc_clk_sel(struct platform_device *pdev, } for (i = 0; i < ARRAY_SIZE(stm32f4_pclk_div); i++) { - if ((rate / stm32f4_pclk_div[i]) <= priv->cfg->max_clk_rate_hz) + if ((rate / stm32f4_pclk_div[i]) <= priv->max_clk_rate) break; } if (i >= ARRAY_SIZE(stm32f4_pclk_div)) { @@ -230,7 +232,7 @@ static int stm32h7_adc_clk_sel(struct platform_device *pdev, if (ckmode) continue; - if ((rate / div) <= priv->cfg->max_clk_rate_hz) + if ((rate / div) <= priv->max_clk_rate) goto out; } } @@ -250,7 +252,7 @@ static int stm32h7_adc_clk_sel(struct platform_device *pdev, if (!ckmode) continue; - if ((rate / div) <= priv->cfg->max_clk_rate_hz) + if ((rate / div) <= priv->max_clk_rate) goto out; } @@ -655,6 +657,7 @@ static int stm32_adc_probe(struct platform_device *pdev) struct device *dev = &pdev->dev; struct device_node *np = pdev->dev.of_node; struct resource *res; + u32 max_rate; int ret; if (!pdev->dev.of_node) @@ -731,6 +734,13 @@ static int stm32_adc_probe(struct platform_device *pdev) priv->common.vref_mv = ret / 1000; dev_dbg(&pdev->dev, "vref+=%dmV\n", priv->common.vref_mv); + ret = of_property_read_u32(pdev->dev.of_node, "st,max-clk-rate-hz", + &max_rate); + if (!ret) + priv->max_clk_rate = min(max_rate, priv->cfg->max_clk_rate_hz); + else + priv->max_clk_rate = priv->cfg->max_clk_rate_hz; + ret = priv->cfg->clk_sel(pdev, priv); if (ret < 0) goto err_hw_stop; |