Re: [PATCH 1/3 v4] spi: s3c64xx: fix broken "cs_gpios" usage in the driver

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Hello Javier,

On 12 June 2014 19:30, Javier Martinez Canillas
<javier.martinez@xxxxxxxxxxxxxxx> wrote:
> Hello Naveen,
>
> On 06/12/2014 03:13 PM, Naveen Krishna Chatradhi wrote:
>> Since, (3146bee spi: s3c64xx: Added provision for dedicated cs pin)
>>
>> spi-s3c64xx.c driver expects
>> 1. chip select gpios from "cs-gpio"(singular) under the
>>    "controller-data" node of the client/slave device of the SPI.
>>
>> 2. "cs-gpio"(singular) entry to be present in the SPI device node.
>>
>> Eg of current broken usage:
>> &spi_1 {
>>       cs-gpio <>;     /* this entry is checked during probe */
>>       ...
>>       slave_node {
>>               controller-data {
>>                       cs-gpio <&gpioa2 5 0>;
>>                       /* This field is parsed during .setup() */
>>               }
>>       };
>> };
>>
>> The following dts files which were using this driver. But,
>> din't have the "cs-gpio" entry under SPI node.
>> -- arch/arm/boot/dts/exynos4210-smdkv310.dts
>> -- arch/arm/boot/dts/exynos4412-trats2.dts
>> -- arch/arm/boot/dts/exynos5250-smdk5250.dts
>>
>> Also, the SPI core and many drivers moved on to using "cs-gpios"
>> from SPI node and removed the gpio handling code from drivers
>> (including spi-s3c64xx.c).
>>
>> Hence, spi-s3c64xx.c is broken since "Jun 21 11:26:12 2013" and
>> considering the time with no compliants about the breakage.
>>
>> We are assuming it is safe to remove the "cs-gpio"(singular) usage
>> from device tree binding of spi-samsung.txt and makes appropriate
>> changes in the driver to use "cs-gpios"(plural) from
>> SPI device node.
>>
>> Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@xxxxxxxxxxx>
>> Acked-by: Rob Herring <robh@xxxxxxxxxx>
>> Cc: Javier Martinez Canillas <javier.martinez@xxxxxxxxxxxxxxx>
>> Cc: Doug Anderson <dianders@xxxxxxxxxxxx>
>> Cc: Tomasz Figa <t.figa@xxxxxxxxxxx>
>> ---
>
> Usually when you send a new version of a series is good to keep a history of the
> patch-set so reviewers don't have to look at the previous threads in order to
> see what changed from version to version.

Yes, I usually keep track of all the changes in my previous CLs.
But, I missed it in this version my bad.

>
> Anything that is between "---" and the actual diff is not part of a commit and
> tools like git am omits that part so that's were you usually describe the history.

I've used it in my earlier patches.
Anyway, Thanks for the detailed information.

>
>>  .../devicetree/bindings/spi/spi-samsung.txt        |    8 ++--
>>  drivers/spi/spi-s3c64xx.c                          |   41 ++++++++------------
>>  2 files changed, 20 insertions(+), 29 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/spi/spi-samsung.txt b/Documentation/devicetree/bindings/spi/spi-samsung.txt
>> index 86aa061..2d29dac 100644
>> --- a/Documentation/devicetree/bindings/spi/spi-samsung.txt
>> +++ b/Documentation/devicetree/bindings/spi/spi-samsung.txt
>> @@ -42,15 +42,13 @@ Optional Board Specific Properties:
>>  - num-cs: Specifies the number of chip select lines supported. If
>>    not specified, the default number of chip select lines is set to 1.
>>
>> +- cs-gpios: should specify GPIOs used for chipselects (see spi-bus.txt)
>> +
>>  SPI Controller specific data in SPI slave nodes:
>>
>>  - The spi slave nodes should provide the following information which is required
>>    by the spi controller.
>>
>> -  - cs-gpio: A gpio specifier that specifies the gpio line used as
>> -    the slave select line by the spi controller. The format of the gpio
>> -    specifier depends on the gpio controller.
>> -
>>    - samsung,spi-feedback-delay: The sampling phase shift to be applied on the
>>      miso line (to account for any lag in the miso line). The following are the
>>      valid values.
>> @@ -85,6 +83,7 @@ Example:
>>               #size-cells = <0>;
>>               pinctrl-names = "default";
>>               pinctrl-0 = <&spi0_bus>;
>> +             cs-gpios = <&gpa2 5 0>;
>>
>>               w25q80bw@0 {
>>                       #address-cells = <1>;
>> @@ -94,7 +93,6 @@ Example:
>>                       spi-max-frequency = <10000>;
>>
>>                       controller-data {
>> -                             cs-gpio = <&gpa2 5 1 0 3>;
>>                               samsung,spi-feedback-delay = <0>;
>>                       };
>>
>> diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
>> index 75a5696..b888c66 100644
>> --- a/drivers/spi/spi-s3c64xx.c
>> +++ b/drivers/spi/spi-s3c64xx.c
>> @@ -197,7 +197,6 @@ struct s3c64xx_spi_driver_data {
>>       struct s3c64xx_spi_dma_data     tx_dma;
>>       struct s3c64xx_spi_port_config  *port_conf;
>>       unsigned int                    port_id;
>> -     bool                            cs_gpio;
>>  };
>>
>>  static void flush_fifo(struct s3c64xx_spi_driver_data *sdd)
>> @@ -776,17 +775,6 @@ static struct s3c64xx_spi_csinfo *s3c64xx_get_slave_ctrldata(
>>               return ERR_PTR(-ENOMEM);
>>       }
>>
>> -     /* The CS line is asserted/deasserted by the gpio pin */
>> -     if (sdd->cs_gpio)
>> -             cs->line = of_get_named_gpio(data_np, "cs-gpio", 0);
>> -
>> -     if (!gpio_is_valid(cs->line)) {
>> -             dev_err(&spi->dev, "chip select gpio is not specified or invalid\n");
>> -             kfree(cs);
>> -             of_node_put(data_np);
>> -             return ERR_PTR(-EINVAL);
>> -     }
>> -
>>       of_property_read_u32(data_np, "samsung,spi-feedback-delay", &fb_delay);
>>       cs->fb_delay = fb_delay;
>>       of_node_put(data_np);
>> @@ -812,6 +800,10 @@ static int s3c64xx_spi_setup(struct spi_device *spi)
>>               spi->controller_data = cs;
>>       }
>>
>> +     /* For the non-DT platforms derive chip selects from controller data */
>> +     if (!spi->dev.of_node)
>> +             spi->cs_gpio = cs->line;
>> +
>>       if (IS_ERR_OR_NULL(cs)) {
>>               dev_err(&spi->dev, "No CS for SPI(%d)\n", spi->chip_select);
>>               return -ENODEV;
>> @@ -819,17 +811,19 @@ static int s3c64xx_spi_setup(struct spi_device *spi)
>>
>>       if (!spi_get_ctldata(spi)) {
>>               /* Request gpio only if cs line is asserted by gpio pins */
>> -             if (sdd->cs_gpio) {
>> -                     err = gpio_request_one(cs->line, GPIOF_OUT_INIT_HIGH,
>> -                                     dev_name(&spi->dev));
>> +             if (gpio_is_valid(spi->cs_gpio)) {
>> +                     err = gpio_request_one(spi->cs_gpio,
>> +                                             GPIOF_OUT_INIT_HIGH,
>> +                                             dev_name(&spi->dev));
>>                       if (err) {
>>                               dev_err(&spi->dev,
>>                                       "Failed to get /CS gpio [%d]: %d\n",
>> -                                     cs->line, err);
>> +                                     spi->cs_gpio, err);
>>                               goto err_gpio_req;
>>                       }
>> -
>> -                     spi->cs_gpio = cs->line;
>> +             } else {
>> +                     dev_err(&spi->dev, "chip select gpio is invalid\n");
>> +                     return -EINVAL;
>>               }
>>
>>               spi_set_ctldata(spi, cs);
>> @@ -884,7 +878,8 @@ setup_exit:
>>       /* setup() returns with device de-selected */
>>       writel(S3C64XX_SPI_SLAVE_SIG_INACT, sdd->regs + S3C64XX_SPI_SLAVE_SEL);
>>
>> -     gpio_free(cs->line);
>> +     if (gpio_is_valid(spi->cs_gpio))
>> +             gpio_free(spi->cs_gpio);
>>       spi_set_ctldata(spi, NULL);
>>
>>  err_gpio_req:
>> @@ -900,10 +895,12 @@ static void s3c64xx_spi_cleanup(struct spi_device *spi)
>>       struct s3c64xx_spi_driver_data *sdd;
>>
>>       sdd = spi_master_get_devdata(spi->master);
>> -     if (spi->cs_gpio) {
>> +     if (gpio_is_valid(spi->cs_gpio)) {
>>               gpio_free(spi->cs_gpio);
>>               if (spi->dev.of_node)
>>                       kfree(cs);
>> +             else
>> +                     spi->cs_gpio = -ENOENT;
>>       }
>>       spi_set_ctldata(spi, NULL);
>>  }
>> @@ -1075,11 +1072,7 @@ static int s3c64xx_spi_probe(struct platform_device *pdev)
>>       sdd->cntrlr_info = sci;
>>       sdd->pdev = pdev;
>>       sdd->sfr_start = mem_res->start;
>> -     sdd->cs_gpio = true;
>>       if (pdev->dev.of_node) {
>> -             if (!of_find_property(pdev->dev.of_node, "cs-gpio", NULL))
>> -                     sdd->cs_gpio = false;
>> -
>>               ret = of_alias_get_id(pdev->dev.of_node, "spi");
>>               if (ret < 0) {
>>                       dev_err(&pdev->dev, "failed to get alias id, errno %d\n",
>>
>
> Your changes look good to me now.
>
> Reviewed-by: Javier Martinez Canillas <javier.martinez@xxxxxxxxxxxxxxx>

Thanks for your review.
>
> Best regards,
> Javier



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