Hi Gwendal, Thanks for the review. On Sat, May 28, 2016 at 10:02:33PM -0700, Gwendal Grignou wrote: > On Fri, May 27, 2016 at 6:39 PM, Brian Norris <briannorris@xxxxxxxxxxxx> wrote: > > Use the new ChromeOS EC EC_CMD_PWM_{GET,SET}_DUTY commands to control > > one or more PWMs attached to the Embedded Controller. Because the EC > > allows us to modify the duty cycle (as a percentage, where U16_MAX is > > 100%) but not the period, we assign the period a fixed value of > > EC_PWM_MAX_DUTY and reject all attempts to change it. > > > > Signed-off-by: Brian Norris <briannorris@xxxxxxxxxxxx> > > --- > > > + */ > > +struct cros_ec_pwm_device { > > + struct device *dev; > > + struct cros_ec_device *ec; > > + struct pwm_chip chip; > > +}; > > + > > +static inline struct cros_ec_pwm_device *pwm_to_cros_ec_pwm(struct pwm_chip *c) > > +{ > > + return container_of(c, struct cros_ec_pwm_device, chip); > > +} > > + > > +static int cros_ec_pwm_set_duty(struct cros_ec_pwm_device *ec_pwm, > > + struct pwm_device *pwm, > > + uint16_t duty) > Given you seprated the pwm stuff from the EC stuff and focusing on > sending a EC command here, the first parameter should be of > cros_ec_device* instead of cros_ec_pwm_device*. Good idea, done. I'll also change the 'pwm_device' arg into just a u8 index, since that's all we care about at this level of abstraction. > > +{ > > + struct cros_ec_device *ec = ec_pwm->ec; > > + struct ec_params_pwm_set_duty *params; > > + struct cros_ec_command *msg; > > + int ret; > > + > > + msg = kzalloc(sizeof(*msg) + sizeof(*params), GFP_KERNEL); > Use an ad-hoc data structure on the stack, so you will always be able > to send the command to the EC. Sure, can do. I guess an anonymous struct will do well here. > > + if (!msg) > > + return -ENOMEM; > > + params = (void *)&msg->data[0]; > > + > > + msg->version = 0; > > + msg->command = EC_CMD_PWM_SET_DUTY; > > + msg->insize = 0; > > + msg->outsize = sizeof(*params); > > + > > + params->duty = duty; > > + params->pwm_type = EC_PWM_TYPE_GENERIC; > > + params->index = pwm->hwpwm; > > + > > + ret = cros_ec_cmd_xfer_status(ec, msg); > > + kfree(msg); > > + return ret; > > +} > > + > > +static int cros_ec_pwm_get_duty(struct cros_ec_pwm_device *ec_pwm, > > + struct pwm_device *pwm) > Idem. Sure. > > +{ > > + struct cros_ec_device *ec = ec_pwm->ec; > > + struct ec_params_pwm_get_duty *params; > > + struct ec_response_pwm_get_duty *resp; > > + struct cros_ec_command *msg; > > + int ret; > > + > > + msg = kzalloc(sizeof(*msg) + max(sizeof(*params), sizeof(*resp)), > Idem. Will do. Here, I guess an anonymous struct containing a union of ec_{params,response}_pwm_get_duty will do it. > > + GFP_KERNEL); > > + if (!msg) > > + return -ENOMEM; > > + params = (void *)&msg->data[0]; > > + resp = (void *)&msg->data[0]; > > + > > + msg->version = 0; > > + msg->command = EC_CMD_PWM_GET_DUTY; > > + msg->insize = sizeof(*params); > > + msg->outsize = sizeof(*resp); > > + > > + params->pwm_type = EC_PWM_TYPE_GENERIC; > > + params->index = pwm->hwpwm; > > + > > + ret = cros_ec_cmd_xfer_status(ec, msg); > > + if (ret < 0) > > + goto out; > > + > > + ret = resp->duty; > > + > > +out: > > + kfree(msg); > > + return ret; > > +} > > + > > +static int cros_ec_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, > > + struct pwm_state *state) > > +{ > > + struct cros_ec_pwm_device *ec_pwm = pwm_to_cros_ec_pwm(chip); > > + > > + /* The EC won't let us change the period */ > > + if (state->period != EC_PWM_MAX_DUTY) > > + return -EINVAL; > > + > > + return cros_ec_pwm_set_duty(ec_pwm, pwm, state->duty_cycle); > I would use ec_pwm->ec here. Sure. > > +} > > + > > +static void cros_ec_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm, > > + struct pwm_state *state) > > +{ > > + struct cros_ec_pwm_device *ec_pwm = pwm_to_cros_ec_pwm(chip); > > + int ret; > > + > > + ret = cros_ec_pwm_get_duty(ec_pwm, pwm); > > + if (ret < 0) { > > + dev_err(chip->dev, "error getting initial duty: %d\n", ret); > > + return; > > + } > > + > > + state->enabled = (ret > 0); > > + state->period = EC_PWM_MAX_DUTY; > > + state->duty_cycle = ret; > > +} > > + > > +static struct pwm_device * > > +cros_ec_pwm_xlate(struct pwm_chip *pc, const struct of_phandle_args *args) > > +{ > > + struct pwm_device *pwm; > > + > > + if (args->args[0] >= pc->npwm) > > + return ERR_PTR(-EINVAL); > > + > > + pwm = pwm_request_from_chip(pc, args->args[0], NULL); > > + if (IS_ERR(pwm)) > > + return pwm; > > + > > + /* The EC won't let us change the period */ > > + pwm->args.period = EC_PWM_MAX_DUTY; > > + > > + return pwm; > > +} > > + > > +static const struct pwm_ops cros_ec_pwm_ops = { > > + .get_state = cros_ec_pwm_get_state, > > + .apply = cros_ec_pwm_apply, > > + .owner = THIS_MODULE, > > +}; > > + > > +static int cros_ec_pwm_probe(struct platform_device *pdev) > > +{ > > + struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent); > > + struct device *dev = &pdev->dev; > > + struct device_node *np = dev->of_node; > > + struct cros_ec_pwm_device *ec_pwm; > > + struct pwm_chip *chip; > > + u32 val; > > + int ret; > > + > > + if (!ec) { > > + dev_err(dev, "no parent EC device\n"); > > + return -EINVAL; > > + } > > + > > + ec_pwm = devm_kzalloc(dev, sizeof(*ec_pwm), GFP_KERNEL); > > + if (!ec_pwm) > > + return -ENOMEM; > > + chip = &ec_pwm->chip; > > + ec_pwm->ec = ec; > > + > > + /* PWM chip */ > > + chip->dev = dev; > > + chip->ops = &cros_ec_pwm_ops; > > + chip->of_xlate = cros_ec_pwm_xlate; > > + chip->of_pwm_n_cells = 1; > > + chip->base = -1; > > + ret = of_property_read_u32(np, "google,max-pwms", &val); > > + if (ret) { > > + dev_err(dev, "Couldn't read max-pwms property: %d\n", ret); > Does it mean this driver does not work when device tree is not used by > the platform? > The rest of the driver still compiles. Correct. I think that's just how many OF-based drivers tend to work; they might *compile* with !CONFIG_OF, but all the useful functions will return errors, and the probe will fail quickly. Anyway, for this particular case (max-pwms), I think we've figured out we can possibly discover this dynamically, so I might drop this property. The bigger problem here is that we're doing PWM device instantiation/matching through the use of OF-based translation (see the ->of_xlate and ->of_pwm_n_cells above). So if you're thinking about using this driver as-is on non-DT platforms, you aren't going to get very far :) Apparently there is some provision for this (see struct pwm_lookup / PWM_LOOKUP()), but I haven't really analyzed how we could adapt this for a cros_ec, non-DT system. Brian > > + return ret; > > + } > > + /* The index field is only 8 bits */ > > + if (val > U8_MAX) { > > + dev_err(dev, "Can't support %u PWMs\n", val); > > + return -EINVAL; > > + } > > + chip->npwm = val; > > + > > + ret = pwmchip_add(chip); > > + if (ret < 0) { > > + dev_err(dev, "cannot register PWM: %d\n", ret); > > + return ret; > > + } > > + > > + platform_set_drvdata(pdev, ec_pwm); > > + > > + return ret; > > +} > > + > > +static int cros_ec_pwm_remove(struct platform_device *dev) > > +{ > > + struct cros_ec_pwm_device *ec_pwm = platform_get_drvdata(dev); > > + struct pwm_chip *chip = &ec_pwm->chip; > > + > > + return pwmchip_remove(chip); > > +} > > + > > +#ifdef CONFIG_OF > > +static const struct of_device_id cros_ec_pwm_of_match[] = { > > + { .compatible = "google,cros-ec-pwm" }, > > + {}, > > +}; > > +MODULE_DEVICE_TABLE(of, cros_ec_pwm_of_match); > > +#endif > > + > > +static struct platform_driver cros_ec_pwm_driver = { > > + .probe = cros_ec_pwm_probe, > > + .remove = cros_ec_pwm_remove, > > + .driver = { > > + .name = "cros-ec-pwm", > > + .of_match_table = of_match_ptr(cros_ec_pwm_of_match), > > + }, > > +}; > > +module_platform_driver(cros_ec_pwm_driver); > > + > > +MODULE_ALIAS("platform:cros-ec-pwm"); > > +MODULE_DESCRIPTION("ChromeOS EC PWM driver"); > > +MODULE_LICENSE("GPL v2"); > > -- > > 2.8.0.rc3.226.g39d4020 > > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html