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I2C support for NXP LPC18xx family

PATCH Superseded Joachim Eastwood 3 participants 7 messages Aug 16, 2015 – Aug 19, 2015

Subsystems (3)
Device tree bindings I2C subsystem host drivers Arm/LPC18XX architecture
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Joachim Eastwood

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#0 lore raw

v2 cover I2C support for NXP LPC18xx family

This patch set adds a I2C driver and documentation for the I2C peripheral found on many NXP LPC MCUs.

The driver is a rework of an old driver by Kevin Wells. It has been modified to support modern resource allocation, device tree and generally cleaned up. Driver was originally written to support the LPC2xxx platforms.

Patches based on i2c/for-next and tested on Embedded Artists' LPC4357 Dev Kit and Hitex LPC4350 Eval board with several I2C devices.

This version address comments from Wolfram Sang.

Changes since v1:
- remove dev_dbg() leftovers from development/debugging
- use i2c_add_adapter
- change return value on NACK and arb lost
(I think all the others should be okay as they are)
- fix 80 char warnings (involved s/reg_base/base)
- rebase on i2c/for-next

Joachim Eastwood (2):
i2c: add i2c-lpc2k driver
doc: dt: add documentation for nxp,lpc1788-i2c

 .../devicetree/bindings/i2c/i2c-lpc2k.txt          |  33 ++
 drivers/i2c/busses/Kconfig                         |  10 +
 drivers/i2c/busses/Makefile                        |   1 +
 drivers/i2c/busses/i2c-lpc2k.c                     | 513 +++++++++++++++++++++
 4 files changed, 557 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/i2c/i2c-lpc2k.txt
 create mode 100644 drivers/i2c/busses/i2c-lpc2k.c
Signature · 1 line
1.8.0
author
#1 lore raw

PATCH v2 1/2 i2c: add i2c-lpc2k driver

Add support for the I2C controller found on several NXP devices including LPC2xxx, LPC178x/7x and LPC18xx/43xx. The controller is implemented as a state machine and the driver act upon the state changes when the bus is accessed.

The I2C controller supports master/slave operation, bus arbitration, programmable clock rate, and speeds up to 1 Mbit/s.

Signed-off-by Joachim Eastwood <[email protected]>
---
 drivers/i2c/busses/Kconfig     |  10 +
 drivers/i2c/busses/Makefile    |   1 +
 drivers/i2c/busses/i2c-lpc2k.c | 513 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 524 insertions(+)
 create mode 100644 drivers/i2c/busses/i2c-lpc2k.c
drivers/i2c/busses/Kconfig +10 -0
index 0b798ae708fe..48f4b796003c 100644
@@ -619,6 +619,16 @@ config I2C_KEMPLD
 	  This driver can also be built as a module. If so, the module
 	  will be called i2c-kempld.
 
+config I2C_LPC2K
+	tristate "I2C bus support for NXP LPC2K/LPC178x/18xx/43xx"
+	depends on OF && (ARCH_LPC18XX || COMPILE_TEST)
+	help
+	  This driver supports the I2C interface found several NXP
+	  devices including LPC2xxx, LPC178x/7x and LPC18xx/43xx.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called i2c-lpc2k.
+
 config I2C_MESON
 	tristate "Amlogic Meson I2C controller"
 	depends on ARCH_MESON
drivers/i2c/busses/Makefile +1 -0
index 50e8bbb65f1c..6df3b303bd09 100644
@@ -59,6 +59,7 @@ obj-$(CONFIG_I2C_IMX)		+= i2c-imx.o
 obj-$(CONFIG_I2C_IOP3XX)	+= i2c-iop3xx.o
 obj-$(CONFIG_I2C_JZ4780)	+= i2c-jz4780.o
 obj-$(CONFIG_I2C_KEMPLD)	+= i2c-kempld.o
+obj-$(CONFIG_I2C_LPC2K)		+= i2c-lpc2k.o
 obj-$(CONFIG_I2C_MESON)		+= i2c-meson.o
 obj-$(CONFIG_I2C_MPC)		+= i2c-mpc.o
 obj-$(CONFIG_I2C_MT65XX)	+= i2c-mt65xx.o
drivers/i2c/busses/i2c-lpc2k.c new file +513 -0

513 lines not on this page · raw message

Signature · 1 line
1.8.0
#2 lore raw

PATCH v2 1/2 i2c: add i2c-lpc2k driver

On 16 Aug 08:10 PM, Joachim Eastwood wrote:
[..]

Quoted 11 lines
drivers/i2c/busses/i2c-lpc2k.c new file +11 -0
+
+static int i2c_lpc2k_clear_arb(struct lpc2k_i2c *i2c)
+{
+	unsigned long timeout = jiffies + msecs_to_jiffies(1000);
+
+	/*
+	 * If the transfer needs to abort for some reason, we'll try to
+	 * force a stop condition to clear any pending bus conditions
+	 */
+	writel(LPC24XX_STO, i2c->base + LPC24XX_I2CONSET);
+

drivers/i2c/busses/i2c-lpc2k.c line 116

Quoted 10 lines
drivers/i2c/busses/i2c-lpc2k.c new file +10 -0
+	/* Wait for status change */
+	while (readl(i2c->base + LPC24XX_I2STAT) != M_I2C_IDLE) {
+		if (time_after(jiffies, timeout)) {
+			/* Bus was not idle, try to reset adapter */
+			i2c_lpc2k_reset(i2c);
+			return -EBUSY;
+		}
+
+		cpu_relax();
+	}

I believe you can use readl_{relaxed}_poll_timeout_{atomic} here.

Ccing Ariel, maybe he can help with a test.

Signature · 2 lines
Ezequiel Garcia, VanguardiaSur
www.vanguardiasur.com.ar
author
#3 lore raw

PATCH v2 1/2 i2c: add i2c-lpc2k driver

Quoted 17 lines · Ezequiel Garcia

On 16 Aug 08:10 PM, Joachim Eastwood wrote:
[..]

Quoted 15 lines
drivers/i2c/busses/i2c-lpc2k.c new file +15 -0
+
+static int 2(struct lpc2k_i2c *i2c)
+{
+     unsigned long timeout = jiffies + msecs_to_jiffies(1000);
+
+     /*1
+      * If the transfer needs to abort for some reason, we'll try to
+      * force a stop condition to clear any pending bus conditions
+      */
+     writel(LPC24XX_STO, i2c->base + LPC24XX_I2CONSET);
+
+     /* Wait for status change */
+     while (readl(i2c->base + LPC24XX_I2STAT) != M_I2C_IDLE) {
+             if (time_after(jiffies, timeout)) {
+                     /* Bus was not idle, try to reset adapter */
Quoted 8 lines

drivers/i2c/busses/i2c-lpc2k.c line 116

Quoted 6 lines
drivers/i2c/busses/i2c-lpc2k.c new file +6 -0
+                     i2c_lpc2k_reset(i2c);
+                     return -EBUSY;
+             }
+
+             cpu_relax();
+     }

I believe you can use readl_{relaxed}_poll_timeout_{atomic} here.

I did consider it, but since I don't have a good to way test the code path I left it as it was.
Also since readl_{relaxed}_poll_timeout_{atomic} takes parameters in us it seemed unsuitable for a 1s total sleep, but I may be wrong.

Quoted 1 line

Ccing Ariel, maybe he can help with a test.

That would be great.

regards,
Joachim Eastwood

author
#4 lore raw

PATCH v2 2/2 doc: dt: add documentation for nxp,lpc1788-i2c

In reply to Joachim Eastwood

Add binding documentation for the nxp,lpc1788-i2c controller which also can be found on LPC2xxx, LPC178x/7x and LPC18xx/43xx devices.

Signed-off-by Joachim Eastwood <[email protected]>
---
 .../devicetree/bindings/i2c/i2c-lpc2k.txt          | 33 ++++++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/i2c/i2c-lpc2k.txt
Documentation/devicetree/bindings/i2c/i2c-lpc2k.txt new file +33 -0
new file mode 100644
index 000000000000..4101aa621ad4
@@ -0,0 +1,33 @@
+NXP I2C controller for LPC2xxx/178x/18xx/43xx
+
+Required properties:
+ - compatible: must be "nxp,lpc1788-i2c"
+ - reg: physical address and length of the device registers
+ - interrupts: a single interrupt specifier
+ - clocks: clock for the device
+ - #address-cells: should be <1>
+ - #size-cells: should be <0>
+
+Optional properties:
+- clock-frequency: the desired I2C bus clock frequency in Hz; in
+  absence of this property the default value is used (100 kHz).
+
+Example:
+i2c0: i2c at 400a1000 {
+	compatible = "nxp,lpc1788-i2c";
+	reg = <0x400a1000 0x1000>;
+	interrupts = <18>;
+	clocks = <&ccu1 CLK_APB1_I2C0>;
+	#address-cells = <1>;
+	#size-cells = <0>;
+};
+
+&i2c0 {
+	clock-frequency = <400000>;
+
+	lm75 at 48 {
+		compatible = "nxp,lm75";
+		reg = <0x48>;
+	};
+};
+
Signature · 1 line
1.8.0
Applied
#5 lore raw

v2 cover I2C support for NXP LPC18xx family

In reply to Joachim Eastwood
Quoted 21 lines · Joachim Eastwood

This patch set adds a I2C driver and documentation for the I2C peripheral found on many NXP LPC MCUs.

The driver is a rework of an old driver by Kevin Wells. It has been modified to support modern resource allocation, device tree and generally cleaned up. Driver was originally written to support the LPC2xxx platforms.

Patches based on i2c/for-next and tested on Embedded Artists' LPC4357 Dev Kit and Hitex LPC4350 Eval board with several I2C devices.

This version address comments from Wolfram Sang.

Changes since v1:
- remove dev_dbg() leftovers from development/debugging
- use i2c_add_adapter
- change return value on NACK and arb lost
(I think all the others should be okay as they are)
- fix 80 char warnings (involved s/reg_base/base)
- rebase on i2c/for-next

Quoted 3 lines

Joachim Eastwood (2):
i2c: add i2c-lpc2k driver
doc: dt: add documentation for nxp,lpc1788-i2c

Applied to for-next, thanks!

Changes regarding readl_poll_timeout() can be sent incrementally.

author
#6 lore raw

v2 cover I2C support for NXP LPC18xx family

Quoted 22 lines · Wolfram Sang
Quoted 21 lines · Joachim Eastwood

This patch set adds a I2C driver and documentation for the I2C peripheral found on many NXP LPC MCUs.

The driver is a rework of an old driver by Kevin Wells. It has been modified to support modern resource allocation, device tree and generally cleaned up. Driver was originally written to support the LPC2xxx platforms.

Patches based on i2c/for-next and tested on Embedded Artists' LPC4357 Dev Kit and Hitex LPC4350 Eval board with several I2C devices.

This version address comments from Wolfram Sang.

Changes since v1:
- remove dev_dbg() leftovers from development/debugging
- use i2c_add_adapter
- change return value on NACK and arb lost
(I think all the others should be okay as they are)
- fix 80 char warnings (involved s/reg_base/base)
- rebase on i2c/for-next

Quoted 5 lines
Quoted 3 lines

Joachim Eastwood (2):
i2c: add i2c-lpc2k driver
doc: dt: add documentation for nxp,lpc1788-i2c

Applied to for-next, thanks!

Thanks, Wolfram.

Quoted 1 line

Changes regarding readl_poll_timeout() can be sent incrementally.

Got it. I'll see if I can figure out a way to test the code path properly.

regards,
Joachim Eastwood