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Subject[PATCH 2/3] mtd: rawnand: stm32_fmc2: Add NAND Write Protect support
Date
This patch adds the support of the WP# signal. WP will be disabled in
probe/resume callbacks and will be enabled in remove/suspend callbacks.

Signed-off-by: Christophe Kerello <christophe.kerello@foss.st.com>
---
drivers/mtd/nand/raw/stm32_fmc2_nand.c | 40 +++++++++++++++++++++++++-
1 file changed, 39 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/raw/stm32_fmc2_nand.c b/drivers/mtd/nand/raw/stm32_fmc2_nand.c
index 97b4e02e43e4..87c1c7dd97eb 100644
--- a/drivers/mtd/nand/raw/stm32_fmc2_nand.c
+++ b/drivers/mtd/nand/raw/stm32_fmc2_nand.c
@@ -9,6 +9,7 @@
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/errno.h>
+#include <linux/gpio/consumer.h>
#include <linux/interrupt.h>
#include <linux/iopoll.h>
#include <linux/mfd/syscon.h>
@@ -231,6 +232,7 @@ struct stm32_fmc2_timings {

struct stm32_fmc2_nand {
struct nand_chip chip;
+ struct gpio_desc *wp_gpio;
struct stm32_fmc2_timings timings;
int ncs;
int cs_used[FMC2_MAX_CE];
@@ -1747,6 +1749,18 @@ static const struct nand_controller_ops stm32_fmc2_nfc_controller_ops = {
.setup_interface = stm32_fmc2_nfc_setup_interface,
};

+static void stm32_fmc2_nfc_wp_enable(struct stm32_fmc2_nand *nand)
+{
+ if (nand->wp_gpio)
+ gpiod_set_value(nand->wp_gpio, 1);
+}
+
+static void stm32_fmc2_nfc_wp_disable(struct stm32_fmc2_nand *nand)
+{
+ if (nand->wp_gpio)
+ gpiod_set_value(nand->wp_gpio, 0);
+}
+
static int stm32_fmc2_nfc_parse_child(struct stm32_fmc2_nfc *nfc,
struct device_node *dn)
{
@@ -1785,6 +1799,18 @@ static int stm32_fmc2_nfc_parse_child(struct stm32_fmc2_nfc *nfc,
nand->cs_used[i] = cs;
}

+ nand->wp_gpio = devm_gpiod_get_from_of_node(nfc->dev, dn,
+ "wp-gpios", 0,
+ GPIOD_OUT_HIGH, "wp");
+ if (IS_ERR(nand->wp_gpio)) {
+ ret = PTR_ERR(nand->wp_gpio);
+ if (ret != -ENOENT)
+ return dev_err_probe(nfc->dev, ret,
+ "failed to request WP GPIO\n");
+
+ nand->wp_gpio = NULL;
+ }
+
nand_set_flash_node(&nand->chip, dn);

return 0;
@@ -1956,10 +1982,12 @@ static int stm32_fmc2_nfc_probe(struct platform_device *pdev)
chip->options |= NAND_BUSWIDTH_AUTO | NAND_NO_SUBPAGE_WRITE |
NAND_USES_DMA;

+ stm32_fmc2_nfc_wp_disable(nand);
+
/* Scan to find existence of the device */
ret = nand_scan(chip, nand->ncs);
if (ret)
- goto err_release_dma;
+ goto err_wp_enable;

ret = mtd_device_register(mtd, NULL, 0);
if (ret)
@@ -1972,6 +2000,9 @@ static int stm32_fmc2_nfc_probe(struct platform_device *pdev)
err_nand_cleanup:
nand_cleanup(chip);

+err_wp_enable:
+ stm32_fmc2_nfc_wp_enable(nand);
+
err_release_dma:
if (nfc->dma_ecc_ch)
dma_release_channel(nfc->dma_ecc_ch);
@@ -2012,15 +2043,20 @@ static int stm32_fmc2_nfc_remove(struct platform_device *pdev)

clk_disable_unprepare(nfc->clk);

+ stm32_fmc2_nfc_wp_enable(nand);
+
return 0;
}

static int __maybe_unused stm32_fmc2_nfc_suspend(struct device *dev)
{
struct stm32_fmc2_nfc *nfc = dev_get_drvdata(dev);
+ struct stm32_fmc2_nand *nand = &nfc->nand;

clk_disable_unprepare(nfc->clk);

+ stm32_fmc2_nfc_wp_enable(nand);
+
pinctrl_pm_select_sleep_state(dev);

return 0;
@@ -2042,6 +2078,8 @@ static int __maybe_unused stm32_fmc2_nfc_resume(struct device *dev)

stm32_fmc2_nfc_init(nfc);

+ stm32_fmc2_nfc_wp_disable(nand);
+
for (chip_cs = 0; chip_cs < FMC2_MAX_CE; chip_cs++) {
if (!(nfc->cs_assigned & BIT(chip_cs)))
continue;
--
2.25.1
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