Re: [PATCH 2/4] mfd: simple-mfd-i2c: Adds Ampere's Altra SMpro support

[Quan Nguyen]

On 26/02/2021 15:31, Lee Jones wrote:
On Thu, 25 Feb 2021, Quan Nguyen wrote:
Adds an MFD driver for SMpro found on the Mt.Jade hardware reference
platform with Ampere's Altra processor family.

Signed-off-by: Quan Nguyen <q...@os.amperecomputing.com>
---
  drivers/mfd/Kconfig          | 10 ++++++++++
  drivers/mfd/simple-mfd-i2c.c | 15 +++++++++++++--
  2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index b74efa469e90..5414371bdea1 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -77,6 +77,16 @@ config MFD_AS3711
        help
          Support for the AS3711 PMIC from AMS
  
+config MFD_SMPRO
+       tristate "Ampere Computing MFD SMpro core driver"
+       select MFD_SIMPLE_MFD_I2C

Nice to see another user here.

+       help
+         Say yes here to enable SMpro driver support for Ampere's Altra
+         processor family.
+
+         Ampere's Altra SMpro exposes an I2C regmap interface that can
+         be accessed by child devices.
+
  config MFD_AS3722
        tristate "ams AS3722 Power Management IC"
        select MFD_CORE
diff --git a/drivers/mfd/simple-mfd-i2c.c b/drivers/mfd/simple-mfd-i2c.c
index 87f684cff9a1..0459a9fbd3f5 100644
--- a/drivers/mfd/simple-mfd-i2c.c
+++ b/drivers/mfd/simple-mfd-i2c.c
@@ -21,14 +21,24 @@ static const struct regmap_config simple_regmap_config = {
        .val_bits = 8,
  };
  
+static const struct regmap_config simple_word_regmap_config = {
+       .reg_bits = 8,
+       .val_bits = 16,
+};
+
  static int simple_mfd_i2c_probe(struct i2c_client *i2c)
  {
        const struct regmap_config *config;
        struct regmap *regmap;
  
  	config = device_get_match_data(&i2c->dev);
-       if (!config)
-               config = &simple_regmap_config;
+       if (!config) {
+               if (of_device_is_compatible(i2c->dev.of_node,
+                                               "ampere,ac01-smpro"))

Could you use 'struct of_device_id's .data attribute instead please?

Thank you, but I'm not sure if I got it right.

Do you mean we could use .data attribute to get the expected 
reg_bits/val_bits values and translate them to simple_word_regmap_config 
without the need to match the compatible string ?

+                       config = &simple_word_regmap_config;
+               else
+                       config = &simple_regmap_config;
+       }
  
  	regmap = devm_regmap_init_i2c(i2c, config);
        if (IS_ERR(regmap))
@@ -39,6 +49,7 @@ static int simple_mfd_i2c_probe(struct i2c_client *i2c)
  
  static const struct of_device_id simple_mfd_i2c_of_match[] = {
        { .compatible = "kontron,sl28cpld" },
+       { .compatible = "ampere,ac01-smpro" },
        {}
  };
  MODULE_DEVICE_TABLE(of, simple_mfd_i2c_of_match);