From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Alain Volmat <alain.volmat@st.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
devicetree <devicetree@vger.kernel.org>,
Alexandre TORGUE <alexandre.torgue@st.com>,
Wolfram Sang <wsa@the-dreams.de>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
pierre-yves.mordret@st.com, Rob Herring <robh+dt@kernel.org>,
linux-i2c <linux-i2c@vger.kernel.org>,
Maxime Coquelin <mcoquelin.stm32@gmail.com>,
fabrice.gasnier@st.com, linux-stm32@st-md-mailman.stormreply.com,
linux-arm Mailing List <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 2/2] i2c: i2c-stm32f7: allows for any bus frequency
Date: Wed, 25 Mar 2020 20:53:45 +0200 [thread overview]
Message-ID: <CAHp75VdPCWdpGo=2n9g0ivti-g2m4jZ=cG4BKHBLk8BVDzaCyg@mail.gmail.com> (raw)
In-Reply-To: <1585161361-3408-3-git-send-email-alain.volmat@st.com>
On Wed, Mar 25, 2020 at 8:38 PM Alain Volmat <alain.volmat@st.com> wrote:
>
> Do not limitate to the 3 (100KHz, 400KHz, 1MHz) bus frequency but
> instead allows any frequency (if it matches timing requirements).
> Depending on the requested frequency, use the spec data from either
> Standard, Fast or Fast Plus mode.
>
> Hardcoding of min/max bus frequencies is removed and is instead computed.
>
> The driver do not use anymore speed identifier but instead handle
> directly the frequency and figure out the spec data (necessary
> for the computation of the timing register) based on the frequency.
...
> +static struct stm32f7_i2c_spec *get_specs(u32 rate)
> +{
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(i2c_specs); i++)
> + if (rate <= i2c_specs[i].rate)
> + return &i2c_specs[i];
> +
> + /* NOT REACHED */
> + return ERR_PTR(-EINVAL);
WARN_ONCE() ?
> +}
...
> - if ((tscl_l < i2c_specs[setup->speed].l_min) ||
> + if ((tscl_l < specs->l_min) ||
> (i2cclk >=
> ((tscl_l - af_delay_min - dnf_delay) / 4))) {
Perhaps squash above two to one line at the same time?
...
> + int i;
> +
> + for (i = ARRAY_SIZE(i2c_specs) - 1; i >= 0; i--)
Perhaps
int i = ARRAY_SIZE(i2c_specs);
while(i--)
?
> + if (i2c_specs[i].rate < rate)
> + return i2c_specs[i].rate;
--
With Best Regards,
Andy Shevchenko
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next prev parent reply other threads:[~2020-03-25 18:54 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-25 18:35 [PATCH 0/2] i2c: i2c-stm32f7: allow range of I2C bus frequency Alain Volmat
2020-03-25 18:36 ` [PATCH 1/2] dt-bindings: i2c: i2c-stm32f7: allow clock-frequency range Alain Volmat
2020-03-25 18:36 ` [PATCH 2/2] i2c: i2c-stm32f7: allows for any bus frequency Alain Volmat
2020-03-25 18:53 ` Andy Shevchenko [this message]
2020-03-26 10:12 ` Alain Volmat
2020-03-26 11:38 ` Andy Shevchenko
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