Re: [PATCH v5 17/26] mtd: nand: omap2: Implement NAND ready using gpiolib

From: Roger Quadros
Date: Mon Mar 07 2016 - 04:12:52 EST


+ Boris

On 05/03/16 03:46, Brian Norris wrote:
> + Boris
>
> On Fri, Feb 19, 2016 at 11:15:39PM +0200, Roger Quadros wrote:
>> The GPMC WAIT pin status are now available over gpiolib.
>> Update the omap_dev_ready() function to use gpio instead of
>> directly accessing GPMC register space.
>>
>> Signed-off-by: Roger Quadros <rogerq@xxxxxx>
>> ---
>> .../devicetree/bindings/mtd/gpmc-nand.txt | 2 ++
>> drivers/mtd/nand/omap2.c | 29 ++++++++++++++--------
>> include/linux/platform_data/mtd-nand-omap2.h | 2 +-
>> 3 files changed, 21 insertions(+), 12 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/mtd/gpmc-nand.txt b/Documentation/devicetree/bindings/mtd/gpmc-nand.txt
>> index 810b87b..256bb86 100644
>> --- a/Documentation/devicetree/bindings/mtd/gpmc-nand.txt
>> +++ b/Documentation/devicetree/bindings/mtd/gpmc-nand.txt
>> @@ -48,6 +48,7 @@ Optional properties:
>> locating ECC errors for BCHx algorithms. SoC devices which have
>> ELM hardware engines should specify this device node in .dtsi
>> Using ELM for ECC error correction frees some CPU cycles.
>> + - rb-gpios: GPIO specifier for the ready/busy# pin.
>
> ^^ Looks better, I think.
>
> Brian
>
>>
>> For inline partition table parsing (optional):
>>
>> @@ -78,6 +79,7 @@ Example for an AM33xx board:
>> ti,nand-xfer-type = "polled";
>> interrupt-parent = <&gpmc>;
>> interrupts = <0>, <1>;
>> + rb-gpios = <&gpmc 0 GPIO_ACTIVE_HIGH>; /* gpmc_wait0 */
>>
>> gpmc,sync-clk-ps = <0>;
>> gpmc,cs-on-ns = <0>;
>> diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
>> index 0a637c4..e7939f1 100644
>> --- a/drivers/mtd/nand/omap2.c
>> +++ b/drivers/mtd/nand/omap2.c
>> @@ -12,6 +12,7 @@
>> #include <linux/dmaengine.h>
>> #include <linux/dma-mapping.h>
>> #include <linux/delay.h>
>> +#include <linux/gpio/consumer.h>
>> #include <linux/module.h>
>> #include <linux/interrupt.h>
>> #include <linux/jiffies.h>
>> @@ -183,6 +184,8 @@ struct omap_nand_info {
>> struct nand_ecclayout oobinfo;
>> /* fields specific for BCHx_HW ECC scheme */
>> struct device *elm_dev;
>> + /* NAND ready gpio */
>> + struct gpio_desc *ready_gpiod;
>> };
>>
>> static inline struct omap_nand_info *mtd_to_omap(struct mtd_info *mtd)
>> @@ -1024,21 +1027,16 @@ static int omap_wait(struct mtd_info *mtd, struct nand_chip *chip)
>> }
>>
>> /**
>> - * omap_dev_ready - calls the platform specific dev_ready function
>> + * omap_dev_ready - checks the NAND Ready GPIO line
>> * @mtd: MTD device structure
>> + *
>> + * Returns true if ready and false if busy.
>> */
>> static int omap_dev_ready(struct mtd_info *mtd)
>> {
>> - unsigned int val = 0;
>> struct omap_nand_info *info = mtd_to_omap(mtd);
>>
>> - val = readl(info->reg.gpmc_status);
>> -
>> - if ((val & 0x100) == 0x100) {
>> - return 1;
>> - } else {
>> - return 0;
>> - }
>> + return gpiod_get_value(info->ready_gpiod);
>> }
>>
>> /**
>> @@ -1754,7 +1752,9 @@ static int omap_nand_probe(struct platform_device *pdev)
>> info->gpmc_cs = pdata->cs;
>> info->reg = pdata->reg;
>> info->ecc_opt = pdata->ecc_opt;
>> - info->dev_ready = pdata->dev_ready;
>> + if (pdata->dev_ready)
>> + dev_info(&pdev->dev, "pdata->dev_ready is deprecated\n");
>> +
>> info->xfer_type = pdata->xfer_type;
>> info->devsize = pdata->devsize;
>> info->elm_of_node = pdata->elm_of_node;
>> @@ -1786,6 +1786,13 @@ static int omap_nand_probe(struct platform_device *pdev)
>> nand_chip->IO_ADDR_W = nand_chip->IO_ADDR_R;
>> nand_chip->cmd_ctrl = omap_hwcontrol;
>>
>> + info->ready_gpiod = devm_gpiod_get_optional(&pdev->dev, "rb",
>> + GPIOD_IN);
>> + if (IS_ERR(info->ready_gpiod)) {
>> + dev_err(dev, "failed to get ready gpio\n");
>> + return PTR_ERR(info->ready_gpiod);
>> + }
>> +
>> /*
>> * If RDY/BSY line is connected to OMAP then use the omap ready
>> * function and the generic nand_wait function which reads the status
>> @@ -1793,7 +1800,7 @@ static int omap_nand_probe(struct platform_device *pdev)
>> * chip delay which is slightly more than tR (AC Timing) of the NAND
>> * device and read status register until you get a failure or success
>> */
>> - if (info->dev_ready) {
>> + if (info->ready_gpiod) {
>> nand_chip->dev_ready = omap_dev_ready;
>> nand_chip->chip_delay = 0;
>> } else {
>> diff --git a/include/linux/platform_data/mtd-nand-omap2.h b/include/linux/platform_data/mtd-nand-omap2.h
>> index 7f6de53..17d57a1 100644
>> --- a/include/linux/platform_data/mtd-nand-omap2.h
>> +++ b/include/linux/platform_data/mtd-nand-omap2.h
>> @@ -71,7 +71,6 @@ struct omap_nand_platform_data {
>> int cs;
>> struct mtd_partition *parts;
>> int nr_parts;
>> - bool dev_ready;
>> bool flash_bbt;
>> enum nand_io xfer_type;
>> int devsize;
>> @@ -82,5 +81,6 @@ struct omap_nand_platform_data {
>> /* deprecated */
>> struct gpmc_nand_regs reg;
>> struct device_node *of_node;
>> + bool dev_ready;
>> };
>> #endif
>> --
>> 2.1.4
>>