[PATCH v4 2/3] memory: omap-gpmc: add support for wait pin polarity

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From: Benedikt Niedermayr <benedikt.niedermayr@xxxxxxxxxxx>

The waitpin polarity can be configured via the WAITPIN<X>POLARITY bits
in the GPMC_CONFIG register. This is currently not supported by the
driver. This patch adds support for setting the required register bits
with the "gpmc,wait-pin-polarity" dt-property.

Signed-off-by: Benedikt Niedermayr <benedikt.niedermayr@xxxxxxxxxxx>
---
 drivers/memory/omap-gpmc.c              | 22 ++++++++++++++++++++++
 include/linux/platform_data/gpmc-omap.h |  6 ++++++
 2 files changed, 28 insertions(+)

diff --git a/drivers/memory/omap-gpmc.c b/drivers/memory/omap-gpmc.c
index e3674a15b934..66dd7dd80653 100644
--- a/drivers/memory/omap-gpmc.c
+++ b/drivers/memory/omap-gpmc.c
@@ -132,6 +132,7 @@
 #define GPMC_CONFIG_DEV_SIZE	0x00000002
 #define GPMC_CONFIG_DEV_TYPE	0x00000003
 
+#define GPMC_CONFIG_WAITPINPOLARITY(pin)	(BIT(pin) << 8)
 #define GPMC_CONFIG1_WRAPBURST_SUPP     (1 << 31)
 #define GPMC_CONFIG1_READMULTIPLE_SUPP  (1 << 30)
 #define GPMC_CONFIG1_READTYPE_ASYNC     (0 << 29)
@@ -1881,6 +1882,21 @@ int gpmc_cs_program_settings(int cs, struct gpmc_settings *p)
 
 	gpmc_cs_write_reg(cs, GPMC_CS_CONFIG1, config1);
 
+	if (p->wait_on_read || p->wait_on_write) {
+		config1 = gpmc_read_reg(GPMC_CONFIG);
+
+		if (p->wait_pin_polarity == WAITPINPOLARITY_ACTIVE_LOW)
+			config1 &= ~GPMC_CONFIG_WAITPINPOLARITY(p->wait_pin);
+		else if (p->wait_pin_polarity == WAITPINPOLARITY_ACTIVE_HIGH)
+			config1 |= GPMC_CONFIG_WAITPINPOLARITY(p->wait_pin);
+		else if (p->wait_pin_polarity != WAITPINPOLARITY_DEFAULT)
+			pr_err("%s: invalid wait-pin-polarity (pin: %d, polarity: %d)\n",
+				__func__, p->wait_pin, p->wait_pin_polarity);
+
+		gpmc_write_reg(GPMC_CONFIG, config1);
+	}
+
+
 	return 0;
 }
 
@@ -1981,6 +1997,12 @@ void gpmc_read_settings_dt(struct device_node *np, struct gpmc_settings *p)
 	}
 
 	if (!of_property_read_u32(np, "gpmc,wait-pin", &p->wait_pin)) {
+
+		p->wait_pin_polarity = WAITPINPOLARITY_DEFAULT;
+		of_property_read_u32(np,
+			"gpmc,wait-pin-polarity",
+			&p->wait_pin_polarity);
+
 		p->wait_on_read = of_property_read_bool(np,
 							"gpmc,wait-on-read");
 		p->wait_on_write = of_property_read_bool(np,
diff --git a/include/linux/platform_data/gpmc-omap.h b/include/linux/platform_data/gpmc-omap.h
index c9cc4e32435d..c46c28069c31 100644
--- a/include/linux/platform_data/gpmc-omap.h
+++ b/include/linux/platform_data/gpmc-omap.h
@@ -136,6 +136,11 @@ struct gpmc_device_timings {
 #define GPMC_MUX_AAD			1	/* Addr-Addr-Data multiplex */
 #define GPMC_MUX_AD			2	/* Addr-Data multiplex */
 
+/* Wait pin polarity values */
+#define WAITPINPOLARITY_DEFAULT -1
+#define WAITPINPOLARITY_ACTIVE_LOW 0
+#define WAITPINPOLARITY_ACTIVE_HIGH 1
+
 struct gpmc_settings {
 	bool burst_wrap;	/* enables wrap bursting */
 	bool burst_read;	/* enables read page/burst mode */
@@ -149,6 +154,7 @@ struct gpmc_settings {
 	u32 device_width;	/* device bus width (8 or 16 bit) */
 	u32 mux_add_data;	/* multiplex address & data */
 	u32 wait_pin;		/* wait-pin to be used */
+	u32 wait_pin_polarity;	/* wait-pin polarity */
 };
 
 /* Data for each chip select */
-- 
2.34.1




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