Re: [PATCH] i2c: add Atmel AT91 driver
Hi Sascha,
Thanks for your review, I'll correct these and send a v2.
Raphaël
2014-07-24 11:34 GMT+02:00 Sascha Hauer :
> Hi Raphaël,
>
> Looks mostly fine to me. Two small comments:
>
> On Wed, Jul 23, 2014 at 12:09:04PM -0700, Raphaël Poggi wrote:
>> +
>> +static int at91_twi_probe(struct device_d *dev)
>> +{
>> + struct at91_twi_dev *i2c_at91;
>> + struct at91_twi_pdata *i2c_data;
>> + int rc;
>> + u32 bus_clk_rate;
>> +
>> + i2c_at91 = kzalloc(sizeof(struct at91_twi_dev), GFP_KERNEL);
>> + if (!i2c_at91) {
>> + rc = -ENOMEM;
>> + goto out_free;
>> + }
>
> You can safely use xzalloc here and skip the result check.
>
>> +
>> + rc = dev_get_drvdata(dev, (unsigned long *)&i2c_data);
>> + if (rc)
>> + goto out_free;
>> +
>> + i2c_at91->pdata = i2c_data;
>> +
>> + i2c_at91->base = dev_request_mem_region(dev, 0);
>> + if (IS_ERR(i2c_at91->base))
>> + return PTR_ERR(i2c_at91->base);
>
> dev_request_mem_region returns NULL on error, not an error pointer.
>
> Sascha
>
> --
> Pengutronix e.K. | |
> Industrial Linux Solutions | http://www.pengutronix.de/ |
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>
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Re: [PATCH] i2c: add Atmel AT91 driver
Hi Raphaël,
Looks mostly fine to me. Two small comments:
On Wed, Jul 23, 2014 at 12:09:04PM -0700, Raphaël Poggi wrote:
> +
> +static int at91_twi_probe(struct device_d *dev)
> +{
> + struct at91_twi_dev *i2c_at91;
> + struct at91_twi_pdata *i2c_data;
> + int rc;
> + u32 bus_clk_rate;
> +
> + i2c_at91 = kzalloc(sizeof(struct at91_twi_dev), GFP_KERNEL);
> + if (!i2c_at91) {
> + rc = -ENOMEM;
> + goto out_free;
> + }
You can safely use xzalloc here and skip the result check.
> +
> + rc = dev_get_drvdata(dev, (unsigned long *)&i2c_data);
> + if (rc)
> + goto out_free;
> +
> + i2c_at91->pdata = i2c_data;
> +
> + i2c_at91->base = dev_request_mem_region(dev, 0);
> + if (IS_ERR(i2c_at91->base))
> + return PTR_ERR(i2c_at91->base);
dev_request_mem_region returns NULL on error, not an error pointer.
Sascha
--
Pengutronix e.K. | |
Industrial Linux Solutions | http://www.pengutronix.de/ |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0|
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917- |
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[PATCH] i2c: add Atmel AT91 driver
Signed-off-by: Raphaël Poggi
---
drivers/i2c/busses/Kconfig| 4 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-at91.c | 438 ++
3 files changed, 443 insertions(+)
create mode 100644 drivers/i2c/busses/i2c-at91.c
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 370abb0..5b75449 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -12,6 +12,10 @@ config I2C_GPIO
This is a very simple bitbanging I2C driver utilizing the
arch-neutral GPIO API to control the SCL and SDA lines.
+config I2C_AT91
+ bool "AT91 I2C Master driver"
+ depends on ARCH_AT91
+
config I2C_IMX
bool "MPC85xx/i.MX I2C Master driver"
depends on (ARCH_IMX && !ARCH_IMX1) || ARCH_MPC85XX
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 9823d1b..cc72b7c 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -1,3 +1,4 @@
+obj-$(CONFIG_I2C_AT91) += i2c-at91.o
obj-$(CONFIG_I2C_GPIO) += i2c-gpio.o
obj-$(CONFIG_I2C_IMX) += i2c-imx.o
obj-$(CONFIG_I2C_OMAP) += i2c-omap.o
diff --git a/drivers/i2c/busses/i2c-at91.c b/drivers/i2c/busses/i2c-at91.c
new file mode 100644
index 000..d743469
--- /dev/null
+++ b/drivers/i2c/busses/i2c-at91.c
@@ -0,0 +1,438 @@
+/*
+ * i2c Support for Atmel's AT91 Two-Wire Interface (TWI)
+ *
+ * Copyright (C) 2011 Weinmann Medical GmbH
+ * Author: Nikolaus Voss
+ *
+ * Evolved from original work by:
+ * Copyright (C) 2004 Rick Bronson
+ * Converted to 2.6 by Andrew Victor
+ *
+ * Borrowed heavily from original work by:
+ * Copyright (C) 2000 Philip Edelbrock
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+
+#define DEFAULT_TWI_CLK_HZ 10 /* max 400 Kbits/s */
+#define AT91_I2C_TIMEOUT (100 * MSECOND) /* transfer timeout */
+#define AT91_I2C_DMA_THRESHOLD 8 /* enable DMA if
transfer size is bigger than this threshold */
+
+/* AT91 TWI register definitions */
+#defineAT91_TWI_CR 0x /* Control Register */
+#defineAT91_TWI_START 0x0001 /* Send a Start Condition */
+#defineAT91_TWI_STOP 0x0002 /* Send a Stop Condition */
+#defineAT91_TWI_MSEN 0x0004 /* Master Transfer Enable */
+#defineAT91_TWI_SVDIS 0x0020 /* Slave Transfer Disable */
+#defineAT91_TWI_QUICK 0x0040 /* SMBus quick command */
+#defineAT91_TWI_SWRST 0x0080 /* Software Reset */
+
+#defineAT91_TWI_MMR0x0004 /* Master Mode Register */
+#defineAT91_TWI_IADRSZ_1 0x0100 /* Internal Device Address Size
*/
+#defineAT91_TWI_MREAD 0x1000 /* Master Read Direction */
+
+#defineAT91_TWI_IADR 0x000c /* Internal Address Register */
+
+#defineAT91_TWI_CWGR 0x0010 /* Clock Waveform Generator Reg
*/
+
+#defineAT91_TWI_SR 0x0020 /* Status Register */
+#defineAT91_TWI_TXCOMP 0x0001 /* Transmission Complete */
+#defineAT91_TWI_RXRDY 0x0002 /* Receive Holding Register
Ready */
+#defineAT91_TWI_TXRDY 0x0004 /* Transmit Holding Register
Ready */
+
+#defineAT91_TWI_OVRE 0x0040 /* Overrun Error */
+#defineAT91_TWI_UNRE 0x0080 /* Underrun Error */
+#defineAT91_TWI_NACK 0x0100 /* Not Acknowledged */
+
+#defineAT91_TWI_IER0x0024 /* Interrupt Enable Register */
+#defineAT91_TWI_IDR0x0028 /* Interrupt Disable Register */
+#defineAT91_TWI_IMR0x002c /* Interrupt Mask Register */
+#defineAT91_TWI_RHR0x0030 /* Receive Holding Register */
+#defineAT91_TWI_THR0x0034 /* Transmit Holding Register */
+
+struct at91_twi_pdata {
+ unsigned clk_max_div;
+ unsigned clk_offset;
+ bool has_unre_flag;
+};
+
+struct at91_twi_dev {
+ struct device *dev;
+ void __iomem *base;
+ struct clk *clk;
+ u8 *buf;
+ size_t buf_len;
+ struct i2c_msg *msg;
+ unsigned imr;
+ unsigned transfer_status;
+ struct i2c_adapter adapter;
+ unsigned twi_cwgr_reg;
+ struct at91_twi_pdata *pdata;
+};
+
+#define to_at91_twi_dev(a) container_of(a, struct at91_twi_dev, adapter)
+
+static unsigned at91_twi_read(struct at91_twi_dev *dev, unsigned reg)
+{
+ return __raw_readl(dev->base + reg);
+}
+
+static void at91_twi_write(struct at91_twi_dev *dev, unsigned reg, uns
