linux-kernel - [PATCH v6 13/48] mfd: ti_am335x_tscadc: Reword the comment explaining the dividers

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Message-Id: <20211015081506.933180-14-miquel.raynal@bootlin.com>
Date:   Fri, 15 Oct 2021 10:14:31 +0200
From:   Miquel Raynal <miquel.raynal@...tlin.com>
To:     Jonathan Cameron <jic23@...nel.org>,
        Lee Jones <lee.jones@...aro.org>, linux-iio@...r.kernel.org,
        linux-omap@...r.kernel.org,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        Ryan Barnett <ryan.barnett@...lins.com>,
        linux-kernel@...r.kernel.org
Cc:     Miquel Raynal <miquel.raynal@...tlin.com>,
        Jonathan Cameron <Jonathan.Cameron@...wei.com>
Subject: [PATCH v6 13/48] mfd: ti_am335x_tscadc: Reword the comment explaining the dividers

The comment misses the main information which is that we assume that a
sample takes 15 ADC clock cycles to be generated. Let's take the
occasion to rework a little bit this comment.

Signed-off-by: Miquel Raynal <miquel.raynal@...tlin.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
---
 drivers/mfd/ti_am335x_tscadc.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/mfd/ti_am335x_tscadc.c b/drivers/mfd/ti_am335x_tscadc.c
index e090fed89c6f..e2c4416f192d 100644
--- a/drivers/mfd/ti_am335x_tscadc.c
+++ b/drivers/mfd/ti_am335x_tscadc.c
@@ -199,12 +199,12 @@ static	int ti_tscadc_probe(struct platform_device *pdev)
 	pm_runtime_get_sync(&pdev->dev);
 
 	/*
-	 * The TSC_ADC_Subsystem has 2 clock domains
-	 * OCP_CLK and ADC_CLK.
-	 * The ADC clock is expected to run at target of 3MHz,
-	 * and expected to capture 12-bit data at a rate of 200 KSPS.
-	 * The TSC_ADC_SS controller design assumes the OCP clock is
-	 * at least 6x faster than the ADC clock.
+	 * The TSC_ADC_Subsystem has 2 clock domains: OCP_CLK and ADC_CLK.
+	 * ADCs produce a 12-bit sample every 15 ADC_CLK cycles.
+	 * am33xx ADCs expect to capture 200ksps.
+	 * We need the ADC clocks to run at 3MHz.
+	 * This frequency is valid since TSC_ADC_SS controller design
+	 * assumes the OCP clock is at least 6x faster than the ADC clock.
 	 */
 	clk = devm_clk_get(&pdev->dev, "adc_tsc_fck");
 	if (IS_ERR(clk)) {
-- 
2.27.0