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

[Guenter Roeck]

On 03/20/2018 02:32 AM, Peter Rosin wrote:

Make the arbitrate and release_bus implementation chip specific.

Signed-off-by: Peter Rosin <p...@axentia.se>

Reviewed-by: Guenter Roeck <li...@roeck-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);