[PATCH v2] iio: adc: lpc18xx_adc: Reorder clk_get_rate function call

clk_get_rate is not guaranteed to work if called before clk_prepare_enable.

Reorder clk_get_rate, so it's called after clk_prepare_enable and
after devm_add_action_or_reset of lpc18xx_clk_disable.

Suggested-by: Jonathan Cameron <jic23@kernel.org>
Acked-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: André Gustavo Nakagomi Lopez <redacted>
---
Change log V1 -> V2:
		  -Fixed typo
		  -Added appropriate Suggested-by and Acked-by tags
 drivers/iio/adc/lpc18xx_adc.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/adc/lpc18xx_adc.c b/drivers/iio/adc/lpc18xx_adc.c
index ceefa4d793cf..ae9c9384f23e 100644
--- a/drivers/iio/adc/lpc18xx_adc.c
+++ b/drivers/iio/adc/lpc18xx_adc.c

@@ -157,9 +157,6 @@ static int lpc18xx_adc_probe(struct platform_device *pdev)
 		return dev_err_probe(&pdev->dev, PTR_ERR(adc->clk),
 				     "error getting clock\n");
 
-	rate = clk_get_rate(adc->clk);
-	clkdiv = DIV_ROUND_UP(rate, LPC18XX_ADC_CLK_TARGET);
-
 	adc->vref = devm_regulator_get(&pdev->dev, "vref");
 	if (IS_ERR(adc->vref))
 		return dev_err_probe(&pdev->dev, PTR_ERR(adc->vref),

@@ -192,6 +189,9 @@ static int lpc18xx_adc_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	rate = clk_get_rate(adc->clk);
+	clkdiv = DIV_ROUND_UP(rate, LPC18XX_ADC_CLK_TARGET);
+
 	adc->cr_reg = (clkdiv << LPC18XX_ADC_CR_CLKDIV_SHIFT) |
 			LPC18XX_ADC_CR_PDN;
 	writel(adc->cr_reg, adc->base + LPC18XX_ADC_CR);

-- 
2.33.0


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On Mon, 25 Oct 2021 09:19:50 -0300
André Gustavo Nakagomi Lopez [off-list ref] wrote:

clk_get_rate is not guaranteed to work if called before clk_prepare_enable.

Reorder clk_get_rate, so it's called after clk_prepare_enable and
after devm_add_action_or_reset of lpc18xx_clk_disable.

Suggested-by: Jonathan Cameron <jic23@kernel.org>
Acked-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: André Gustavo Nakagomi Lopez <redacted>

Thanks. I tweaked the message a little and added a note that this was not
a fix for this particular platform.  Good to avoid chance of cut and paste
into another driver!

Jonathan

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