[U-Boot] [PATCH V2 3/3] dm: gpio: introduce 74x164 driver

[Peng Fan <van.freenix@gmail.com>]

Hi Simon,

On Wed, Apr 20, 2016 at 08:40:45AM -0600, Simon Glass wrote:
>Hi Peng,
>
>On 13 April 2016 at 01:18, Peng Fan <van.freenix@gmail.com> wrote:
>> Introduce driver to support "fairchild,74hc595" devices.
>> 1. Take linux drivers/drivers/gpio/gpio-74x164.c as reference.
>> 2. Following the naming used in Linux driver with gen_7x164 as the prefix.
>> 3. Enable CONFIG_DM_74X164 to use this driver.
>> 4. Follow Documentation/devicetree/bindings/gpio/gpio-74x164.txt to add device
>>    nodes
>> 5. Tested on i.MX6 UltraLite with 74LV595 using gpio command and oscillograph.
>>
>> Signed-off-by: Peng Fan <van.freenix@gmail.com>
>> Cc: Simon Glass <sjg@chromium.org>
>> Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
>> Cc: Chin Liang See <clsee@altera.com>
>> Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
>> Cc: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
>> Cc: Fabio Estevam <fabio.estevam@nxp.com>
>> Cc: Stefano Babic <sbabic@denx.de>
>> ---
>>
>> V2:
>>  Address Simon's comments:
>>  Drop unused dev entry of gen_74x164_priv
>>  Rename gen_74x164_info to gen_74x164_priv
>>  Change u8 to uint
>>  Change EINVAL to ENOSYS
>>  Drop dm_gpio_set_value when probe, since GPIOD_IS_OUT_ACTIVE already
>>  active the gpio.
>>  Drop complicated spi_get_bus_and_cs, use dev_get_parent_priv.
>>  To Kconfig help msg, I add 74lv165 and 75hc595, actually, the linux
>>  one does not contain manufacture info.
>>
>>  drivers/gpio/74x164_gpio.c | 198 +++++++++++++++++++++++++++++++++++++++++++++
>>  drivers/gpio/Kconfig       |   8 ++
>>  drivers/gpio/Makefile      |   1 +
>>  3 files changed, 207 insertions(+)
>>  create mode 100644 drivers/gpio/74x164_gpio.c
>
>This looks good, but can you please adjust as below?
>
>>
>> diff --git a/drivers/gpio/74x164_gpio.c b/drivers/gpio/74x164_gpio.c
>> new file mode 100644
>> index 0000000..1791dc8
>> --- /dev/null
>> +++ b/drivers/gpio/74x164_gpio.c
>> @@ -0,0 +1,198 @@
>> +/*
>> + * Take drivers/gpio/gpio-74x164.c as reference.
>> + *
>> + * 74Hx164 - Generic serial-in/parallel-out 8-bits shift register GPIO driver
>> + *
>> + * Copyright (C) 2016 Peng Fan <van.freenix@gmail.com>
>> + *
>> + * SPDX-License-Identifier:    GPL-2.0+
>> + *
>> + */
>> +
>> +#include <common.h>
>> +#include <errno.h>
>> +#include <dm.h>
>> +#include <fdtdec.h>
>> +#include <malloc.h>
>> +#include <asm/gpio.h>
>> +#include <asm/io.h>
>> +#include <dt-bindings/gpio/gpio.h>
>> +#include <spi.h>
>> +
>> +DECLARE_GLOBAL_DATA_PTR;
>> +
>> +/*
>> + * struct gen_74x164_priv - Data for 74Hx164
>> + *
>> + * @slave: spi slave
>> + * @oe: OE pin
>> + * @nregs: number of registers
>> + * @buffer: buffer for chained chips
>> + */
>> +#define GEN_74X164_NUMBER_GPIOS 8
>> +
>> +struct gen_74x164_priv {
>> +       struct spi_slave *slave;
>> +       struct gpio_desc oe;
>> +       u32 nregs;
>> +       /*
>> +        * Since the nregs are chained, every byte sent will make
>> +        * the previous byte shift to the next register in the
>> +        * chain. Thus, the first byte sent will end up in the last
>> +        * register at the end of the transfer. So, to have a logical
>> +        * numbering, store the bytes in reverse order.
>> +        */
>> +       u8 *buffer;
>> +};
>> +
>> +static int gen_74x164_write_conf(struct udevice *dev)
>> +{
>> +       struct gen_74x164_priv *priv = dev_get_priv(dev);
>> +       struct spi_slave *slave = priv->slave;
>> +       int ret;
>> +
>> +       ret = spi_claim_bus(slave);
>
>We should have a call like dm_claim_bus(struct udevice *dev)
>
>Then you can avoid this priv business. Similarly with
>dm_spi_release_bus() and dm_spi_xfer(). They should be easy to add.
>Can you do a new patch?

Ok. Will fix in V3.

Thanks,
Peng

>
>> +       if (ret)
>> +               return ret;
>> +
>> +       ret = spi_xfer(slave, priv->nregs * 8, priv->buffer, NULL,
>> +                      SPI_XFER_BEGIN | SPI_XFER_END);
>> +
>> +       spi_release_bus(slave);
>> +
>> +       return ret;
>> +}
>> +
>> +static int gen_74x164_get_value(struct udevice *dev, unsigned offset)
>> +{
>> +       struct gen_74x164_priv *priv = dev_get_priv(dev);
>> +       uint bank = priv->nregs - 1 - offset / 8;
>> +       uint pin = offset % 8;
>> +
>> +       return (priv->buffer[bank] >> pin) & 0x1;
>> +}
>> +
>> +static int gen_74x164_set_value(struct udevice *dev, unsigned offset,
>> +                               int value)
>> +{
>> +       struct gen_74x164_priv *priv = dev_get_priv(dev);
>> +       uint bank = priv->nregs - 1 - offset / 8;
>> +       uint pin = offset % 8;
>> +       int ret;
>> +
>> +       if (value)
>> +               priv->buffer[bank] |= 1 << pin;
>> +       else
>> +               priv->buffer[bank] &= ~(1 << pin);
>> +
>> +       ret = gen_74x164_write_conf(dev);
>> +       if (ret)
>> +               return ret;
>> +
>> +       return 0;
>> +}
>> +
>> +static int gen_74x164_direction_input(struct udevice *dev, unsigned offset)
>> +{
>> +       return -ENOSYS;
>> +}
>> +
>> +static int gen_74x164_direction_output(struct udevice *dev, unsigned offset,
>> +                                     int value)
>> +{
>> +       return gen_74x164_set_value(dev, offset, value);
>> +}
>> +
>> +static int gen_74x164_get_function(struct udevice *dev, unsigned offset)
>> +{
>> +       return GPIOF_OUTPUT;
>> +}
>> +
>> +static int gen_74x164_xlate(struct udevice *dev, struct gpio_desc *desc,
>> +                           struct fdtdec_phandle_args *args)
>> +{
>> +       desc->offset = args->args[0];
>> +       desc->flags = args->args[1] & GPIO_ACTIVE_LOW ? GPIOD_ACTIVE_LOW : 0;
>> +
>> +       return 0;
>> +}
>> +
>> +static const struct dm_gpio_ops gen_74x164_ops = {
>> +       .direction_input        = gen_74x164_direction_input,
>> +       .direction_output       = gen_74x164_direction_output,
>> +       .get_value              = gen_74x164_get_value,
>> +       .set_value              = gen_74x164_set_value,
>> +       .get_function           = gen_74x164_get_function,
>> +       .xlate                  = gen_74x164_xlate,
>> +};
>> +
>> +static int gen_74x164_probe(struct udevice *dev)
>> +{
>> +       struct gen_74x164_priv *priv = dev_get_priv(dev);
>> +       struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
>> +       char *str, name[32];
>> +       int ret;
>> +       const void *fdt = gd->fdt_blob;
>> +       int node = dev->of_offset;
>> +
>> +       snprintf(name, sizeof(name), "%s_", dev->name);
>> +       str = strdup(name);
>> +       if (!str)
>> +               return -ENOMEM;
>> +
>> +       /*
>> +        * See Linux kernel:
>> +        * Documentation/devicetree/bindings/gpio/gpio-74x164.txt
>> +        */
>> +       priv->nregs = fdtdec_get_int(fdt, node, "registers-number", 1);
>> +       priv->buffer = calloc(priv->nregs, sizeof(u8));
>> +       if (!priv->buffer) {
>> +               ret = -ENOMEM;
>> +               goto free_str;
>> +       }
>> +
>> +       ret = fdtdec_get_byte_array(fdt, node, "registers-default",
>> +                                   priv->buffer, priv->nregs);
>> +       if (ret)
>> +               dev_dbg(dev, "No registers-default property\n");
>> +
>> +       ret = gpio_request_by_name(dev, "oe-gpios", 0, &priv->oe,
>> +                                  GPIOD_IS_OUT | GPIOD_IS_OUT_ACTIVE);
>> +       if (ret) {
>> +               dev_err(dev, "No oe-pins property\n");
>> +               goto free_buf;
>> +       }
>> +
>> +       uc_priv->bank_name = str;
>> +       uc_priv->gpio_count = priv->nregs * 8;
>> +
>> +       priv->slave = dev_get_parent_priv(dev);
>> +
>> +       ret = gen_74x164_write_conf(dev);
>> +       if (ret)
>> +               goto free_buf;
>> +
>> +       dev_dbg(dev, "%s is ready\n", dev->name);
>> +
>> +       return 0;
>> +
>> +free_buf:
>> +       free(priv->buffer);
>> +free_str:
>> +       free(str);
>> +       return ret;
>> +}
>> +
>> +static const struct udevice_id gen_74x164_ids[] = {
>> +       { .compatible = "fairchild,74hc595" },
>> +       { }
>> +};
>> +
>> +U_BOOT_DRIVER(74x164) = {
>> +       .name           = "74x164",
>> +       .id             = UCLASS_GPIO,
>> +       .ops            = &gen_74x164_ops,
>> +       .probe          = gen_74x164_probe,
>> +       .priv_auto_alloc_size = sizeof(struct gen_74x164_priv),
>> +       .of_match       = gen_74x164_ids,
>> +};
>> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
>> index 8ff657c..7aecd13 100644
>> --- a/drivers/gpio/Kconfig
>> +++ b/drivers/gpio/Kconfig
>> @@ -112,6 +112,14 @@ config MVEBU_GPIO
>>         help
>>           Say yes here to support Marvell MVEBU (Armada XP/38x) GPIOs.
>>
>> +config DM_74X164
>> +       bool "74x164 serial-in/parallel-out 8-bits shift register"
>> +       depends on DM_GPIO
>> +       help
>> +         Driver for 74x164 compatible serial-in/parallel-out 8-outputs
>> +         shift registers, such as 74lv165, 74hc595.
>> +         This driver can be used to provide access to more gpio outputs.
>> +
>>  config DM_PCA953X
>>         bool "PCA95[357]x, PCA9698, TCA64xx, and MAX7310 I/O ports"
>>         depends on DM_GPIO
>> diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
>> index a7a466c..cca5f39 100644
>> --- a/drivers/gpio/Makefile
>> +++ b/drivers/gpio/Makefile
>> @@ -12,6 +12,7 @@ endif
>>  obj-$(CONFIG_DM_GPIO)          += gpio-uclass.o
>>
>>  obj-$(CONFIG_DM_PCA953X)       += pca953x_gpio.o
>> +obj-$(CONFIG_DM_74X164)                += 74x164_gpio.o
>>
>>  obj-$(CONFIG_AT91_GPIO)        += at91_gpio.o
>>  obj-$(CONFIG_ATMEL_PIO4)       += atmel_pio4.o
>> --
>> 2.6.2
>>
>
>Regards,
>Simon