RE: [PATCH v6 3/3] pinctrl: Add Xilinx ZynqMP pinctrl driver support

[Sai Krishna Potthuri <lakshmis@xilinx.com>]

Hi Andy Shevchenko,

Thanks for the review.

> -----Original Message-----
> From: Andy Shevchenko <andy.shevchenko@gmail.com>
> Sent: Friday, April 23, 2021 9:24 PM
> To: Sai Krishna Potthuri <lakshmis@xilinx.com>
> Cc: Linus Walleij <linus.walleij@linaro.org>; Rob Herring
> <robh+dt@kernel.org>; Michal Simek <michals@xilinx.com>; Greg Kroah-
> Hartman <gregkh@linuxfoundation.org>; linux-arm Mailing List <linux-arm-
> kernel@lists.infradead.org>; Linux Kernel Mailing List <linux-
> kernel@vger.kernel.org>; devicetree <devicetree@vger.kernel.org>; open
> list:GPIO SUBSYSTEM <linux-gpio@vger.kernel.org>; git <git@xilinx.com>;
> saikrishna12468@gmail.com
> Subject: Re: [PATCH v6 3/3] pinctrl: Add Xilinx ZynqMP pinctrl driver support
> 
> On Thu, Apr 22, 2021 at 11:31 AM Sai Krishna Potthuri
> <lakshmi.sai.krishna.potthuri@xilinx.com> wrote:
> >
> > Adding pinctrl driver for Xilinx ZynqMP platform.
> > This driver queries pin information from firmware and registers pin
> > control accordingly.
> >
> > Signed-off-by: Sai Krishna Potthuri
> > <lakshmi.sai.krishna.potthuri@xilinx.com>
> 
> You may reduce the number of LOCs by joining some lines. See below.
> 
> ...
> 
> > +config PINCTRL_ZYNQMP
> > +       tristate "Pinctrl driver for Xilinx ZynqMP"
> > +       depends on ZYNQMP_FIRMWARE
> > +       select PINMUX
> > +       select GENERIC_PINCONF
> > +       default ZYNQMP_FIRMWARE
> > +       help
> > +         This selects the pinctrl driver for Xilinx ZynqMP platform.
> > +         This driver will query the pin information from the firmware
> > +         and allow configuring the pins.
> > +         Configuration can include the mux function to select on those
> > +         pin(s)/group(s), and various pin configuration parameters
> > +         such as pull-up, slew rate, etc.
> 
> Missed module name.
Is this (module name) a configuration option in Kconfig?
> 
> ...
> 
> > +/*
> > + * ZynqMP pin controller
> > + *
> > + * Copyright (C) 2020 Xilinx, Inc.
> 
> 2021?
Couple of versions for this patch series sent in 2020, hence maintaining
the same.
Is it like we maintain the year when this patch series is applied, which is
2021?
> 
> > + *
> > + * Sai Krishna Potthuri <lakshmi.sai.krishna.potthuri@xilinx.com>
> > + * Rajan Vaja <rajan.vaja@xilinx.com> */
> 
> ...
> 
> > +#include <linux/init.h>
> > +#include <linux/module.h>
> > +#include <linux/of_address.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/firmware/xlnx-zynqmp.h>
> 
> ...
> 
> > +static int zynqmp_pinconf_cfg_get(struct pinctrl_dev *pctldev,
> > +                                 unsigned int pin,
> > +                                 unsigned long *config)
> > +{
> > +       unsigned int arg, param = pinconf_to_config_param(*config);
> > +       int ret;
> 
> > +       if (pin >= zynqmp_desc.npins)
> > +               return -EOPNOTSUPP;
> 
> Is it possible?
This is a safe check.
Pin information will get from dt files/Xilinx firmware (query pin information
for a group)/user application and there are chances of getting wrong pin.
> 
> > +       switch (param) {
> > +       case PIN_CONFIG_SLEW_RATE:
> > +               param = PM_PINCTRL_CONFIG_SLEW_RATE;
> > +               ret = zynqmp_pm_pinctrl_get_config(pin, param, &arg);
> > +               break;
> > +       case PIN_CONFIG_BIAS_PULL_UP:
> > +               param = PM_PINCTRL_CONFIG_PULL_CTRL;
> 
> > +               ret = zynqmp_pm_pinctrl_get_config(pin, param, &arg);
> > +               if (arg != PM_PINCTRL_BIAS_PULL_UP)
> > +                       return -EINVAL;
> 
> Error code being shadowed. Instead check it here properly.
Are you mentioning the case where ret is also a non-zero?
If yes, then I will update this check to 
if (!ret && arg != PM_PINCTRL_BIAS_PULL_UP)
	return -EINVAL;
ret non-zero case, we are handling at the end of switch case.
> 
> > +               arg = 1;
> > +               break;
> > +       case PIN_CONFIG_BIAS_PULL_DOWN:
> > +               param = PM_PINCTRL_CONFIG_PULL_CTRL;
> > +               ret = zynqmp_pm_pinctrl_get_config(pin, param, &arg);
> > +               if (arg != PM_PINCTRL_BIAS_PULL_DOWN)
> > +                       return -EINVAL;
> 
> Ditto.
Same as above.
> 
> > +               arg = 1;
> > +               break;
> > +       case PIN_CONFIG_BIAS_DISABLE:
> > +               param = PM_PINCTRL_CONFIG_BIAS_STATUS;
> > +               ret = zynqmp_pm_pinctrl_get_config(pin, param, &arg);
> > +               if (arg != PM_PINCTRL_BIAS_DISABLE)
> > +                       return -EINVAL;
> 
> Ditto.
Same as above.
> 
> > +               arg = 1;
> > +               break;
> > +       case PIN_CONFIG_POWER_SOURCE:
> > +               param = PM_PINCTRL_CONFIG_VOLTAGE_STATUS;
> > +               ret = zynqmp_pm_pinctrl_get_config(pin, param, &arg);
> > +               break;
> > +       case PIN_CONFIG_INPUT_SCHMITT_ENABLE:
> > +               param = PM_PINCTRL_CONFIG_SCHMITT_CMOS;
> > +               ret = zynqmp_pm_pinctrl_get_config(pin, param, &arg);
> > +               break;
> > +       case PIN_CONFIG_DRIVE_STRENGTH:
> > +               param = PM_PINCTRL_CONFIG_DRIVE_STRENGTH;
> > +               ret = zynqmp_pm_pinctrl_get_config(pin, param, &arg);
> > +               switch (arg) {
> > +               case PM_PINCTRL_DRIVE_STRENGTH_2MA:
> > +                       arg = DRIVE_STRENGTH_2MA;
> > +                       break;
> > +               case PM_PINCTRL_DRIVE_STRENGTH_4MA:
> > +                       arg = DRIVE_STRENGTH_4MA;
> > +                       break;
> > +               case PM_PINCTRL_DRIVE_STRENGTH_8MA:
> > +                       arg = DRIVE_STRENGTH_8MA;
> > +                       break;
> > +               case PM_PINCTRL_DRIVE_STRENGTH_12MA:
> > +                       arg = DRIVE_STRENGTH_12MA;
> > +                       break;
> > +               default:
> > +                       /* Invalid drive strength */
> > +                       dev_warn(pctldev->dev,
> > +                                "Invalid drive strength for pin %d\n",
> > +                                pin);
> > +                       return -EINVAL;
> > +               }
> > +               break;
> > +       default:
> > +               ret = -EOPNOTSUPP;
> > +               break;
> > +       }
> > +
> > +       if (ret)
> > +               return ret;
> > +
> > +       param = pinconf_to_config_param(*config);
> > +       *config = pinconf_to_config_packed(param, arg);
> > +
> > +       return 0;
> > +}
> 
> ...
> 
> > +                       ret = -EOPNOTSUPP;
> 
> Isn't it ENOTSUP for all cases here?
Giving 'Operation Not Supported (EOPNOTSUPP)' error, when
driver gets a request for unsupported pin or configuration.
Can you please elaborate your question if I didn't answer properly.
> 
> ...
> 
> > +       ret = zynqmp_pm_query_data(qdata, payload);
> > +       if (ret)
> > +               return ret;
> > +
> > +       *ngroups = payload[1];
> > +
> 
> > +       return ret;
> 
> return 0;
I will fix.
> 
> ...
> 
> > + * Query firmware to get group IDs for each function. Firmware returns
> > + * group IDs. Based on group index for the function, group names in
> 
> on the group
> 
> > + * the function are stored. For example, the first group in "eth0" function
> > + * is named as "eth0_0" and second group as "eth0_1" and so on.
> 
> and the second
> 
> > + *
> > + * Based on the group ID received from the firmware, function stores
> name of
> > + * the group for that group ID. For example, if "eth0" first group ID
> > + * is x, groups[x] name will be stored as "eth0_0".
> > + *
> > + * Once done for each function, each function would have its group names
> > + * and each groups would also have their names.
> 
> each group
I will fix all the above.
> 
> ...
> 
> > +done:
> > +       func->groups = fgroups;
> > +
> > +       return ret;
> 
> return 0; ?
> 
> ...
> 
> > +       *nfuncs = payload[1];
> > +
> > +       return ret;
> 
> Ditto.
> 
> ...
> 
> > +       ret = zynqmp_pm_query_data(qdata, payload);
> > +       if (ret)
> > +               return ret;
> > +
> > +       memcpy(groups, &payload[1],
> PINCTRL_GET_PIN_GROUPS_RESP_LEN);
> > +
> > +       return ret;
> 
> Ditto.
> 
> ...
> 
> > + * Query firmware to get groups available for the given pin.
> > + * Based on the firmware response(group IDs for the pin), add
> > + * pin number to the respective group's pin array.
> > + *
> > + * Once all pins are queries, each groups would have its number
> 
> each group
> 
> > + * of pins and pin numbers data.
> 
> ...
> 
> > +       return ret;
> 
> return 0;
> 
> ...
> 
> > + * Query number of functions and number of function groups (number
> > + * of groups in given function) to allocate required memory buffers
> 
> in the given
> 
> > + * for functions and groups. Once buffers are allocated to store
> > + * functions and groups data, query and store required information
> > + * (number of groups and group names for each function, number of
> > + * pins and pin numbers for each group).
> 
> ...
> 
> > +       pctrl->funcs = funcs;
> > +       pctrl->groups = groups;
> > +
> > +       return ret;
> 
> return 0;
> 
> ...
> 
> > +       *npins = payload[1];
> > +
> > +       return ret;
> 
> Ditto.
I will fix all the above similar comments.
> 
> ...
> 
> > +               dev_err(&pdev->dev, "pin desc prepare fail with %d\n",
> > +                       ret);
> 
> One line.
> 
> ...
> 
> > +               dev_err(&pdev->dev, "function info prepare fail with %d\n",
> > +                       ret);
> 
> Ditto.
I will fix all.
> 
> ...
> 
> > +       pctrl->pctrl = pinctrl_register(&zynqmp_desc, &pdev->dev, pctrl);
> 
> devm_pinctrl_register()
I will update.
> 
> > +       if (IS_ERR(pctrl->pctrl))
> > +               return PTR_ERR(pctrl->pctrl);
> 
> ...
> 
> > +};
> 
> > +
> 
> Extra blank line.
> 
> > +MODULE_DEVICE_TABLE(of, zynqmp_pinctrl_of_match);
> 
> ...
> 
> > +};
> 
> > +
> 
> Ditto.
I see some drivers are maintaining the extra line in above two cases.
We shouldn't maintain extra line after struct declaration?

Regards
Sai Krishna
> 
> > +module_platform_driver(zynqmp_pinctrl_driver);
> 
> --
> With Best Regards,
> Andy Shevchenko