linux-kernel - Re: [PATCH RFC 6/7] i2c: davinci: add support for setting bus frequency

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Message-ID: <CAMRc=McVePrs_+BKkpO3zf_AUcxhzp+8Cf6Tyh1A97nzkx_ZRQ@mail.gmail.com>
Date: Mon, 22 Sep 2025 07:43:31 -0700
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Marcus Folkesson <marcus.folkesson@...il.com>
Cc: linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org, 
	Wolfram Sang <wsa+renesas@...g-engineering.com>, Peter Rosin <peda@...ntia.se>, 
	Michael Hennerich <michael.hennerich@...log.com>, Bartosz Golaszewski <brgl@...ev.pl>, 
	Andi Shyti <andi.shyti@...nel.org>
Subject: Re: [PATCH RFC 6/7] i2c: davinci: add support for setting bus frequency

On Mon, 22 Sep 2025 08:21:01 +0200, Marcus Folkesson
<marcus.folkesson@...il.com> said:
> Populate adapter with clock_hz and set_clk_freq to enable support for
> dynamic bus frequency.
>
> Signed-off-by: Marcus Folkesson <marcus.folkesson@...il.com>
> ---
>  drivers/i2c/busses/i2c-davinci.c | 23 +++++++++++++++++++++++
>  1 file changed, 23 insertions(+)
>
> diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
> index 6b18938457d0c5cabc323c364d9330c2890df107..d3e47738f8ee7e8f69fee49509dcda396c9b7fb6 100644
> --- a/drivers/i2c/busses/i2c-davinci.c
> +++ b/drivers/i2c/busses/i2c-davinci.c
> @@ -279,6 +279,27 @@ static int i2c_davinci_init(struct davinci_i2c_dev *dev)
>  	return 0;
>  }
>
> +static int davinci_i2c_set_clk(struct i2c_adapter *adap, u32 clock_hz)
> +{
> +	struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
> +
> +	if (dev->bus_freq == clock_hz)
> +		return 0;
> +
> +	dev->bus_freq = clock_hz;
> +
> +	/* put I2C into reset */
> +	davinci_i2c_reset_ctrl(dev, 0);
> +
> +	/* compute clock dividers */
> +	i2c_davinci_calc_clk_dividers(dev);
> +
> +	/* Take the I2C module out of reset: */
> +	davinci_i2c_reset_ctrl(dev, 1);
> +
> +	return 0;
> +}
> +
>  /*
>   * This routine does i2c bus recovery by using i2c_generic_scl_recovery
>   * which is provided by I2C Bus recovery infrastructure.
> @@ -810,6 +831,8 @@ static int davinci_i2c_probe(struct platform_device *pdev)
>  	adap->dev.parent = &pdev->dev;
>  	adap->timeout = DAVINCI_I2C_TIMEOUT;
>  	adap->dev.of_node = dev_of_node(&pdev->dev);
> +	adap->clock_hz = dev->bus_freq;
> +	adap->set_clk_freq = davinci_i2c_set_clk;
>
>  	if (dev->has_pfunc)
>  		adap->bus_recovery_info = &davinci_i2c_scl_recovery_info;
>
> --
> 2.50.1
>
>

Acked-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>