From: Vladimir Zapolskiy <vz@mleia.com>
To: Luis Oliveira <Luis.Oliveira@synopsys.com>,
wsa@the-dreams.de, robh+dt@kernel.org, mark.rutland@arm.com,
jarkko.nikula@linux.intel.com, andriy.shevchenko@linux.intel.com,
mika.westerberg@linux.intel.com, linux-i2c@vger.kernel.org,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Ramiro.Oliveira@synopsys.com, Joao.Pinto@synopsys.com,
CARLOS.PALMINHA@synopsys.com
Subject: Re: [PATCH] i2c: core: helper function to detect slave mode
Date: Fri, 6 Jan 2017 23:46:30 +0200 [thread overview]
Message-ID: <73246c4a-504c-52d7-dde4-970a45dca0bd@mleia.com> (raw)
In-Reply-To: <f4ec62119145bc70c938800c91eb396d30457304.1483636071.git.lolivei@synopsys.com>
Hello Luis,
On 01/05/2017 07:24 PM, Luis Oliveira wrote:
> This function has the purpose of mode detection by checking the
> device nodes for a reg matching with the I2C_OWN_SLAVE_ADDREESS flag.
> Currently only checks using OF functions (ACPI slave not supported yet).
>
> Signed-off-by: Luis Oliveira <lolivei@synopsys.com>
> ---
> Due to the need of checking if the I2C slave address is our own (in
> other words: if we are the I2C slave) I created a helper function
> (proposed to me by @Andy) to enable that check.
> Currently (because I am not able to test it using ACPI) it only
> supports devicetree declarations.
>
> drivers/i2c/i2c-core.c | 19 +++++++++++++++++++
> include/linux/i2c.h | 1 +
> 2 files changed, 20 insertions(+)
>
> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> index 3de95a29024c..48e705b23c59 100644
> --- a/drivers/i2c/i2c-core.c
> +++ b/drivers/i2c/i2c-core.c
> @@ -3691,6 +3691,25 @@ int i2c_slave_unregister(struct i2c_client *client)
> return ret;
> }
> EXPORT_SYMBOL_GPL(i2c_slave_unregister);
> +
> +int i2c_slave_mode_detect(struct device *dev)
> +{
> + struct device_node *child;
> + u32 reg;
> +
> + if (IS_BUILTIN(CONFIG_OF) && dev->of_node) {
IS_BUILTIN(CONFIG_OF) looks excessive, check for non-NULL dev->of_node
should be sufficient.
But then you may do for_each_child_of_node() loop totally unconditionally,
because of_get_next_child() correctly handle NULL as the first argument.
> + for_each_child_of_node(dev->of_node, child) {
> + of_property_read_u32(child, "reg", ®);
> + if (reg & I2C_OWN_SLAVE_ADDRESS)
> + return 1;
Leaked incremented reference to a child device node, please add
of_node_put(child) before return in the loop body.
Also reg variable may be uninitialized here, if child device node
does not have "reg" property.
> + }
> + } else if (IS_BUILTIN(CONFIG_ACPI) && ACPI_HANDLE(dev)) {
> + dev_dbg(dev, "ACPI slave is not supported yet\n");
> + }
If so, then it might be better to drop else-if stub for now.
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(i2c_slave_mode_detect);
> +
> #endif
>
> MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
> diff --git a/include/linux/i2c.h b/include/linux/i2c.h
> index b2109c522dec..53cf99569af5 100644
> --- a/include/linux/i2c.h
> +++ b/include/linux/i2c.h
> @@ -282,6 +282,7 @@ enum i2c_slave_event {
>
> extern int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb);
> extern int i2c_slave_unregister(struct i2c_client *client);
> +extern int i2c_slave_mode_detect(struct device *dev);
>
> static inline int i2c_slave_event(struct i2c_client *client,
> enum i2c_slave_event event, u8 *val)
>
--
With best wishes,
Vladimir
next prev parent reply other threads:[~2017-01-06 21:46 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-05 17:24 [PATCH] i2c: core: helper function to detect slave mode Luis Oliveira
2017-01-06 16:29 ` Andy Shevchenko
2017-01-06 17:15 ` Luis Oliveira
2017-01-06 17:17 ` Andy Shevchenko
2017-01-06 17:46 ` Luis Oliveira
2017-01-06 21:32 ` Andy Shevchenko
2017-01-06 16:35 ` Rob Herring
2017-01-06 17:12 ` Luis Oliveira
2017-01-06 21:46 ` Vladimir Zapolskiy [this message]
2017-01-06 22:45 ` Andy Shevchenko
2017-01-06 23:43 ` Vladimir Zapolskiy
2017-01-07 0:19 ` Andy Shevchenko
2017-01-07 1:24 ` Vladimir Zapolskiy
2017-01-12 17:01 ` Andy Shevchenko
2017-01-16 10:32 ` Luis Oliveira
2017-01-16 23:14 ` Vladimir Zapolskiy
2017-01-18 10:59 ` Andy Shevchenko
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