linux-kernel - Re: [PATCH 3/3] i2c: mux: pca9541: prepare for PCA9641 support

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Message-ID: <f8f4693c-245a-7c49-8b0b-ba3590c6b1be@roeck-us.net>
Date:   Tue, 20 Mar 2018 06:22:49 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Peter Rosin <peda@...ntia.se>, linux-kernel@...r.kernel.org
Cc:     Wolfram Sang <wsa@...-dreams.de>,
        Ken Chen <chen.kenyy@...entec.com>, joel@....id.au,
        linux-i2c@...r.kernel.org
Subject: Re: [PATCH 3/3] i2c: mux: pca9541: prepare for PCA9641 support

On 03/20/2018 02:32 AM, Peter Rosin wrote:
> Make the arbitrate and release_bus implementation chip specific.
> 
> Signed-off-by: Peter Rosin <peda@...ntia.se>

Reviewed-by: Guenter Roeck <linux@...ck-us.net>

> ---
>   drivers/i2c/muxes/i2c-mux-pca9541.c | 62 +++++++++++++++++++++++++++----------
>   1 file changed, 45 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/i2c/muxes/i2c-mux-pca9541.c b/drivers/i2c/muxes/i2c-mux-pca9541.c
> index 47685eb4e0e9..cac629e36bf8 100644
> --- a/drivers/i2c/muxes/i2c-mux-pca9541.c
> +++ b/drivers/i2c/muxes/i2c-mux-pca9541.c
> @@ -23,6 +23,7 @@
>   #include <linux/i2c-mux.h>
>   #include <linux/jiffies.h>
>   #include <linux/module.h>
> +#include <linux/of_device.h>
>   #include <linux/platform_data/pca954x.h>
>   #include <linux/slab.h>
>   
> @@ -70,26 +71,22 @@
>   #define SELECT_DELAY_SHORT	50
>   #define SELECT_DELAY_LONG	1000
>   
> -struct pca9541 {
> -	struct i2c_client *client;
> -	unsigned long select_timeout;
> -	unsigned long arb_timeout;
> +enum chip_name {
> +	pca9541,
>   };
>   
> -static const struct i2c_device_id pca9541_id[] = {
> -	{"pca9541", 0},
> -	{}
> +struct chip_desc {
> +	int (*arbitrate)(struct i2c_client *client);
> +	void (*release_bus)(struct i2c_client *client);
>   };
>   
> -MODULE_DEVICE_TABLE(i2c, pca9541_id);
> +struct pca9541 {
> +	const struct chip_desc *chip;
>   
> -#ifdef CONFIG_OF
> -static const struct of_device_id pca9541_of_match[] = {
> -	{ .compatible = "nxp,pca9541" },
> -	{}
> +	struct i2c_client *client;
> +	unsigned long select_timeout;
> +	unsigned long arb_timeout;
>   };
> -MODULE_DEVICE_TABLE(of, pca9541_of_match);
> -#endif
>   
>   static int pca9541_mybus(int ctl)
>   {
> @@ -318,7 +315,7 @@ static int pca9541_select_chan(struct i2c_mux_core *muxc, u32 chan)
>   		/* force bus ownership after this time */
>   
>   	do {
> -		ret = pca9541_arbitrate(client);
> +		ret = data->chip->arbitrate(client);
>   		if (ret)
>   			return ret < 0 ? ret : 0;
>   
> @@ -336,10 +333,32 @@ static int pca9541_release_chan(struct i2c_mux_core *muxc, u32 chan)
>   	struct pca9541 *data = i2c_mux_priv(muxc);
>   	struct i2c_client *client = data->client;
>   
> -	pca9541_release_bus(client);
> +	data->chip->release_bus(client);
>   	return 0;
>   }
>   
> +static const struct chip_desc chips[] = {
> +	[pca9541] = {
> +		.arbitrate = pca9541_arbitrate,
> +		.release_bus = pca9541_release_bus,
> +	},
> +};
> +
> +static const struct i2c_device_id pca9541_id[] = {
> +	{ "pca9541", pca9541 },
> +	{}
> +};
> +
> +MODULE_DEVICE_TABLE(i2c, pca9541_id);
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id pca9541_of_match[] = {
> +	{ .compatible = "nxp,pca9541", .data = &chips[pca9541] },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, pca9541_of_match);
> +#endif
> +
>   /*
>    * I2C init/probing/exit functions
>    */
> @@ -348,6 +367,8 @@ static int pca9541_probe(struct i2c_client *client,
>   {
>   	struct i2c_adapter *adap = client->adapter;
>   	struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);
> +	const struct of_device_id *match;
> +	const struct chip_desc *chip;
>   	struct i2c_mux_core *muxc;
>   	struct pca9541 *data;
>   	int force;
> @@ -356,12 +377,18 @@ static int pca9541_probe(struct i2c_client *client,
>   	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE_DATA))
>   		return -ENODEV;
>   
> +	match = of_match_device(of_match_ptr(pca9541_of_match), &client->dev);
> +	if (match)
> +		chip = of_device_get_match_data(&client->dev);
> +	else
> +		chip = &chips[id->driver_data];
> +
>   	/*
>   	 * I2C accesses are unprotected here.
>   	 * We have to lock the adapter before releasing the bus.
>   	 */
>   	i2c_lock_adapter(adap);
> -	pca9541_release_bus(client);
> +	chip->release_bus(client);
>   	i2c_unlock_adapter(adap);
>   
>   	/* Create mux adapter */
> @@ -376,6 +403,7 @@ static int pca9541_probe(struct i2c_client *client,
>   		return -ENOMEM;
>   
>   	data = i2c_mux_priv(muxc);
> +	data->chip = chip;
>   	data->client = client;
>   
>   	i2c_set_clientdata(client, muxc);
>