Messages in this thread | | | Subject | Re: [RFC PATCH RESEND 1/3] mfd: upboard: Add UP2 platform controller driver | From | Andy Shevchenko <> | Date | Wed, 25 Apr 2018 18:57:30 +0300 |
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On Sat, 2018-04-21 at 09:50 +0100, Javier Arteaga wrote: > UP Squared (UP2) is a x86 SBC from AAEON based on Intel Apollo Lake.
> +config MFD_UPBOARD > + tristate "UP Squared" > + depends on ACPI > + depends on GPIOLIB > + select MFD_CORE > + select REGMAP > + help > + If you say yes here you get support for the platform > controller > + of the UP Squared single-board computer. > + > + This driver provides common support for accessing the > device, > + additional drivers must be enabled in order to use the > + functionality of the device. > + > + This driver can also be built as a module. If so, the > module > + will be called upboard.
"upboard"
> > +static int upboard_read(void *context, unsigned int reg, unsigned int > *val) > +{ > + const struct upboard * const upboard = context; > + int i; > + > + gpiod_set_value(upboard->clear_gpio, 0); > + gpiod_set_value(upboard->clear_gpio, 1); > + > + reg |= UPBOARD_READ_FLAG; > + > + for (i = UPBOARD_ADDRESS_SIZE; i >= 0; i--) { > + gpiod_set_value(upboard->strobe_gpio, 0); > + gpiod_set_value(upboard->datain_gpio, (reg >> i) & > 0x1); > + gpiod_set_value(upboard->strobe_gpio, 1); > + } > +
> + gpiod_set_value(upboard->strobe_gpio, 0); > + *val = 0; > + > + for (i = UPBOARD_REGISTER_SIZE - 1; i >= 0; i--) { > + gpiod_set_value(upboard->strobe_gpio, 1); > + gpiod_set_value(upboard->strobe_gpio, 0); > + *val |= gpiod_get_value(upboard->dataout_gpio) << i; > + } > + > + gpiod_set_value(upboard->strobe_gpio, 1);
Can't you rewrite this like
for (addr) { strobe(0) data(x) strobe(1) }
for (register) { strobe(0) val = data(x) strobe(1) }
val &= BIT(register_size); strobe(0)
?
> + > + return 0; > +}; > + > +static int upboard_write(void *context, unsigned int reg, unsigned > int val) > +{ > + const struct upboard * const upboard = context; > + int i; > + > + gpiod_set_value(upboard->clear_gpio, 0); > + gpiod_set_value(upboard->clear_gpio, 1); > + > + for (i = UPBOARD_ADDRESS_SIZE; i >= 0; i--) { > + gpiod_set_value(upboard->strobe_gpio, 0); > + gpiod_set_value(upboard->datain_gpio, (reg >> i) & > 0x1); > + gpiod_set_value(upboard->strobe_gpio, 1); > + } > + > + gpiod_set_value(upboard->strobe_gpio, 0); > + > + for (i = UPBOARD_REGISTER_SIZE - 1; i >= 0; i--) { > + gpiod_set_value(upboard->datain_gpio, (val >> i) & > 0x1); > + gpiod_set_value(upboard->strobe_gpio, 1); > + gpiod_set_value(upboard->strobe_gpio, 0); > + } > + > + gpiod_set_value(upboard->strobe_gpio, 1);
Similar here:
for (addr) { strobe(0) data(x) strobe(1) }
for (register) { strobe(0) data(x) strobe(1) }
strobe(0) strobe(1)
?
> + > + return 0; > +};
Moreover these two functions have duplications, i.e.
static ... upboard_clear() { clear(0) clear(1) }
static ... upboard_set_address() { for (addr) { ... } }
Additional question is about spi-bitbang and i2c-gpio. Can one of them be utilized here? Why not?
> +struct upboard_data { > + const struct regmap_config *regmapconf; > + const struct mfd_cell *cells; > + size_t ncells; > +};
> +static int upboard_init_gpio(struct upboard *upboard) > +{ > + struct gpio_desc *enable_gpio; > + > + enable_gpio = devm_gpiod_get(upboard->dev, "enable", > GPIOD_OUT_LOW); > + if (IS_ERR(enable_gpio)) > + return PTR_ERR(enable_gpio);
> + gpiod_set_value(enable_gpio, 1);
When do you disable it? Why not?
> + return 0; > +}
> + > +static int upboard_check_supported(struct upboard *upboard) > +{
> + const unsigned int AAEON_MANUFACTURER_ID = 0x01; > + const unsigned int SUPPORTED_FW_MAJOR = 0x0;
Why to hide here instead of putting at the top of file as defined constants?
> + unsigned int platform_id, manufacturer_id; > + unsigned int firmware_id, build, major, minor, patch; > + int ret;
> + build = (firmware_id >> 12) & 0xf; > + major = (firmware_id >> 8) & 0xf; > + minor = (firmware_id >> 4) & 0xf;
> + patch = firmware_id & 0xf;
For style purposes you can use (firmware >> 0) & 0xf here
> +static int upboard_probe(struct platform_device *pdev) > +{ > + struct upboard *upboard; > + const struct acpi_device_id *id; > + const struct upboard_data *upboard_data; > + int ret;
> + id = acpi_match_device(upboard_acpi_match, &pdev->dev); > + if (!id) > + return -ENODEV; > + > + upboard_data = (const struct upboard_data *) id->driver_data;
Use new API for that.
> +MODULE_LICENSE("GPL");
License mismatch.
> +#define UPBOARD_ADDRESS_SIZE 7 > +#define UPBOARD_REGISTER_SIZE 16
> +#define UPBOARD_READ_FLAG BIT(UPBOARD_ADDRESS_SIZE)
It's not clear why this one is defined in this way. Comment is needed.
-- Andy Shevchenko <andriy.shevchenko@linux.intel.com> Intel Finland Oy
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