From: Jonathan Cameron <jic23@kernel.org>
To: Billy Tsai <billy_tsai@aspeedtech.com>
Cc: <lars@metafoo.de>, <pmeerw@pmeerw.net>, <robh+dt@kernel.org>,
<joel@jms.id.au>, <andrew@aj.id.au>, <p.zabel@pengutronix.de>,
<lgirdwood@gmail.com>, <broonie@kernel.org>,
<linux-iio@vger.kernel.org>, <devicetree@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
<linux-aspeed@lists.ozlabs.org>, <linux-kernel@vger.kernel.org>,
<BMC-SW@aspeedtech.com>
Subject: Re: [RESEND v4 11/15] iio: adc: aspeed: Fix the calculate error of clock.
Date: Sun, 29 Aug 2021 16:33:46 +0100 [thread overview]
Message-ID: <20210829163346.501fdb43@jic23-huawei> (raw)
In-Reply-To: <20210824091243.9393-12-billy_tsai@aspeedtech.com>
On Tue, 24 Aug 2021 17:12:39 +0800
Billy Tsai <billy_tsai@aspeedtech.com> wrote:
> The adc clcok formula is
clock
> ast2400/2500:
> ADC clock period = PCLK * 2 * (ADC0C[31:17] + 1) * (ADC0C[9:0] + 1)
> ast2600:
> ADC clock period = PCLK * 2 * (ADC0C[15:0] + 1)
> They all have one fixed divided 2 and the legacy driver didn't handle it.
> This patch register the fixed factory clock device as the parent of adc
> clock scaler to fix this issue.
What are the impacts of this being wrong before? Is this something we
should look to backport?
Comment inline.
>
> Signed-off-by: Billy Tsai <billy_tsai@aspeedtech.com>
> ---
> drivers/iio/adc/aspeed_adc.c | 26 ++++++++++++++++++++++++++
> 1 file changed, 26 insertions(+)
>
> diff --git a/drivers/iio/adc/aspeed_adc.c b/drivers/iio/adc/aspeed_adc.c
> index ea3e9a52fcc9..8fe7da1a651f 100644
> --- a/drivers/iio/adc/aspeed_adc.c
> +++ b/drivers/iio/adc/aspeed_adc.c
> @@ -4,6 +4,12 @@
> *
> * Copyright (C) 2017 Google, Inc.
> * Copyright (C) 2021 Aspeed Technology Inc.
> + *
> + * ADC clock formula:
> + * Ast2400/Ast2500:
> + * clock period = period of PCLK * 2 * (ADC0C[31:17] + 1) * (ADC0C[9:0] + 1)
> + * Ast2600:
> + * clock period = period of PCLK * 2 * (ADC0C[15:0] + 1)
> */
>
> #include <linux/clk.h>
> @@ -77,6 +83,7 @@ struct aspeed_adc_data {
> struct regulator *regulator;
> void __iomem *base;
> spinlock_t clk_lock;
> + struct clk_hw *fixed_div_clk;
> struct clk_hw *clk_prescaler;
> struct clk_hw *clk_scaler;
> struct reset_control *rst;
> @@ -196,6 +203,13 @@ static void aspeed_adc_unregister_divider(void *data)
> clk_hw_unregister_divider(clk);
> }
>
> +static void aspeed_adc_unregister_fixed_divider(void *data)
> +{
> + struct clk_hw *clk = data;
> +
> + clk_hw_unregister_fixed_factor(clk);
> +}
> +
> static void aspeed_adc_reset_assert(void *data)
> {
> struct reset_control *rst = data;
> @@ -312,6 +326,18 @@ static int aspeed_adc_probe(struct platform_device *pdev)
> /* Register ADC clock prescaler with source specified by device tree. */
> spin_lock_init(&data->clk_lock);
> snprintf(clk_parent_name, 32, of_clk_get_parent_name(pdev->dev.of_node, 0));
> + snprintf(clk_name, 32, "%s-fixed-div", data->model_data->model_name);
ARRAY_SIZE
> + data->fixed_div_clk = clk_hw_register_fixed_factor(
> + &pdev->dev, clk_name, clk_parent_name, 0, 1, 2);
> + if (IS_ERR(data->fixed_div_clk))
> + return PTR_ERR(data->fixed_div_clk);
> +
> + ret = devm_add_action_or_reset(data->dev,
> + aspeed_adc_unregister_fixed_divider,
> + data->clk_prescaler);
> + if (ret)
> + return ret;
> + snprintf(clk_parent_name, 32, clk_name);
> if (data->model_data->need_prescaler) {
> snprintf(clk_name, 32, "%s-prescaler",
> data->model_data->model_name);
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next prev parent reply other threads:[~2021-08-29 15:32 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-24 9:12 [RESEND v4 00/15] Add support for ast2600 ADC Billy Tsai
2021-08-24 9:12 ` [RESEND v4 01/15] dt-bindings: iio: adc: Add ast2600-adc bindings Billy Tsai
2021-08-24 9:12 ` [RESEND v4 02/15] iio: adc: aspeed: completes the bitfield declare Billy Tsai
2021-08-29 15:07 ` Jonathan Cameron
2021-08-24 9:12 ` [RESEND v4 03/15] iio: adc: aspeed: set driver data when adc probe Billy Tsai
2021-08-29 15:08 ` Jonathan Cameron
2021-08-24 9:12 ` [RESEND v4 04/15] iio: adc: aspeed: Keep model data to driver data Billy Tsai
2021-08-24 9:12 ` [RESEND v4 05/15] iio: adc: aspeed: Refactory model data structure Billy Tsai
2021-08-29 15:13 ` Jonathan Cameron
2021-08-24 9:12 ` [RESEND v4 06/15] iio: adc: aspeed: Add vref config function Billy Tsai
2021-08-24 9:12 ` [RESEND v4 07/15] iio: adc: aspeed: Set num_channels with model data Billy Tsai
2021-08-24 9:12 ` [RESEND v4 08/15] iio: adc: aspeed: Use model_data to set clk scaler Billy Tsai
2021-08-24 9:12 ` [RESEND v4 09/15] iio: adc: aspeed: Use devm_add_action_or_reset Billy Tsai
2021-08-24 9:12 ` Billy Tsai
2021-08-24 9:12 ` [RESEND v4 10/15] iio: adc: aspeed: Support ast2600 adc Billy Tsai
2021-08-29 15:31 ` Jonathan Cameron
2021-08-24 9:12 ` [RESEND v4 11/15] iio: adc: aspeed: Fix the calculate error of clock Billy Tsai
2021-08-29 15:33 ` Jonathan Cameron [this message]
2021-08-24 9:12 ` [RESEND v4 12/15] iio: adc: aspeed: Add func to set sampling rate Billy Tsai
2021-08-24 9:12 ` [RESEND v4 13/15] iio: adc: aspeed: Add compensation phase Billy Tsai
2021-08-24 9:12 ` [RESEND v4 14/15] iio: adc: aspeed: Support battery sensing Billy Tsai
2021-08-24 9:12 ` [RESEND v4 15/15] iio: adc: aspeed: Get and set trimming data Billy Tsai
2021-08-24 9:12 ` Billy Tsai
[not found] ` <202108250006.17P06IgG097015@twspam01.aspeedtech.com>
2021-08-29 15:20 ` [RESEND v4 08/15] iio: adc: aspeed: Use model_data to set clk scaler Jonathan Cameron
[not found] ` <202108250004.17P04FdD094082@twspam01.aspeedtech.com>
2021-08-29 15:25 ` [RESEND v4 09/15] iio: adc: aspeed: Use devm_add_action_or_reset Jonathan Cameron
[not found] ` <202108250003.17P03KRU092474@twspam01.aspeedtech.com>
2021-08-29 15:36 ` [RESEND v4 12/15] iio: adc: aspeed: Add func to set sampling rate Jonathan Cameron
2021-08-30 8:35 ` Billy Tsai
2021-08-30 9:52 ` Jonathan Cameron
[not found] ` <202108250006.17P066YP096721@twspam01.aspeedtech.com>
2021-08-29 15:39 ` [RESEND v4 13/15] iio: adc: aspeed: Add compensation phase Jonathan Cameron
[not found] ` <202108250005.17P05agj096445@twspam01.aspeedtech.com>
2021-08-29 15:43 ` [RESEND v4 14/15] iio: adc: aspeed: Support battery sensing Jonathan Cameron
[not found] ` <202108250007.17P07NFj097422@twspam01.aspeedtech.com>
2021-08-29 15:45 ` [RESEND v4 15/15] iio: adc: aspeed: Get and set trimming data Jonathan Cameron
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