@@ -305,6 +305,8 @@ extern struct platform_device iop3xx_dma_1_channel;
extern struct platform_device iop3xx_aau_channel;
extern struct platform_device iop3xx_i2c0_device;
extern struct platform_device iop3xx_i2c1_device;
+extern struct gpiod_lookup_table iop3xx_i2c0_gpio_lookup;
+extern struct gpiod_lookup_table iop3xx_i2c1_gpio_lookup;
#endif
@@ -24,6 +24,7 @@
#include <linux/platform_device.h>
#include <linux/i2c.h>
#include <linux/gpio.h>
+#include <linux/gpio/machine.h>
#include <mach/hardware.h>
#include <linux/io.h>
#include <linux/irq.h>
@@ -211,6 +212,8 @@ static void __init em7210_init_machine(void)
{
register_iop32x_gpio();
platform_device_register(&em7210_serial_device);
+ gpiod_add_lookup_table(&iop3xx_i2c0_gpio_lookup);
+ gpiod_add_lookup_table(&iop3xx_i2c1_gpio_lookup);
platform_device_register(&iop3xx_i2c0_device);
platform_device_register(&iop3xx_i2c1_device);
platform_device_register(&em7210_flash_device);
@@ -25,6 +25,7 @@
#include <linux/i2c.h>
#include <linux/platform_device.h>
#include <linux/io.h>
+#include <linux/gpio/machine.h>
#include <mach/hardware.h>
#include <asm/irq.h>
#include <asm/mach/arch.h>
@@ -189,6 +190,8 @@ static void glantank_power_off(void)
static void __init glantank_init_machine(void)
{
register_iop32x_gpio();
+ gpiod_add_lookup_table(&iop3xx_i2c0_gpio_lookup);
+ gpiod_add_lookup_table(&iop3xx_i2c1_gpio_lookup);
platform_device_register(&iop3xx_i2c0_device);
platform_device_register(&iop3xx_i2c1_device);
platform_device_register(&glantank_flash_device);
@@ -26,6 +26,7 @@
#include <linux/mtd/physmap.h>
#include <linux/platform_device.h>
#include <linux/io.h>
+#include <linux/gpio/machine.h>
#include <mach/hardware.h>
#include <asm/cputype.h>
#include <asm/irq.h>
@@ -285,6 +286,8 @@ void ep80219_power_off(void)
static void __init iq31244_init_machine(void)
{
register_iop32x_gpio();
+ gpiod_add_lookup_table(&iop3xx_i2c0_gpio_lookup);
+ gpiod_add_lookup_table(&iop3xx_i2c1_gpio_lookup);
platform_device_register(&iop3xx_i2c0_device);
platform_device_register(&iop3xx_i2c1_device);
platform_device_register(&iq31244_flash_device);
@@ -23,6 +23,7 @@
#include <linux/mtd/physmap.h>
#include <linux/platform_device.h>
#include <linux/io.h>
+#include <linux/gpio/machine.h>
#include <mach/hardware.h>
#include <asm/irq.h>
#include <asm/mach/arch.h>
@@ -172,6 +173,8 @@ static struct platform_device iq80321_serial_device = {
static void __init iq80321_init_machine(void)
{
register_iop32x_gpio();
+ gpiod_add_lookup_table(&iop3xx_i2c0_gpio_lookup);
+ gpiod_add_lookup_table(&iop3xx_i2c1_gpio_lookup);
platform_device_register(&iop3xx_i2c0_device);
platform_device_register(&iop3xx_i2c1_device);
platform_device_register(&iq80321_flash_device);
@@ -31,6 +31,7 @@
#include <linux/reboot.h>
#include <linux/io.h>
#include <linux/gpio.h>
+#include <linux/gpio/machine.h>
#include <mach/hardware.h>
#include <asm/irq.h>
#include <asm/mach/arch.h>
@@ -345,6 +346,7 @@ device_initcall(n2100_request_gpios);
static void __init n2100_init_machine(void)
{
register_iop32x_gpio();
+ gpiod_add_lookup_table(&iop3xx_i2c0_gpio_lookup);
platform_device_register(&iop3xx_i2c0_device);
platform_device_register(&n2100_flash_device);
platform_device_register(&n2100_serial_device);
@@ -19,6 +19,7 @@
#include <linux/tty.h>
#include <linux/serial_core.h>
#include <linux/io.h>
+#include <linux/gpio/machine.h>
#include <asm/pgtable.h>
#include <asm/page.h>
#include <asm/mach/map.h>
@@ -37,6 +38,29 @@
#define IRQ_IOP3XX_I2C_1 IRQ_IOP33X_I2C_1
#endif
+/*
+ * Each of the I2C busses have corresponding GPIO lines, and the driver
+ * need to access these directly to drive the bus low at times.
+ */
+
+struct gpiod_lookup_table iop3xx_i2c0_gpio_lookup = {
+ .dev_id = "IOP3xx-I2C.0",
+ .table = {
+ GPIO_LOOKUP("gpio-iop", 7, "scl", GPIO_ACTIVE_HIGH),
+ GPIO_LOOKUP("gpio-iop", 6, "sda", GPIO_ACTIVE_HIGH),
+ { }
+ },
+};
+
+struct gpiod_lookup_table iop3xx_i2c1_gpio_lookup = {
+ .dev_id = "IOP3xx-I2C.1",
+ .table = {
+ GPIO_LOOKUP("gpio-iop", 5, "scl", GPIO_ACTIVE_HIGH),
+ GPIO_LOOKUP("gpio-iop", 4, "sda", GPIO_ACTIVE_HIGH),
+ { }
+ },
+};
+
static struct resource iop3xx_i2c0_resources[] = {
[0] = {
.start = 0xfffff680,
@@ -40,6 +40,7 @@ static int iop3xx_gpio_probe(struct platform_device *pdev)
gc->base = 0;
gc->owner = THIS_MODULE;
+ gc->label = "gpio-iop";
return devm_gpiochip_add_data(&pdev->dev, gc, NULL);
}
@@ -38,7 +38,7 @@
#include <linux/platform_device.h>
#include <linux/i2c.h>
#include <linux/io.h>
-#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
#include "i2c-iop3xx.h"
@@ -71,17 +71,16 @@ iop3xx_i2c_enable(struct i2c_algo_iop3xx_data *iop3xx_adap)
/*
* Every time unit enable is asserted, GPOD needs to be cleared
- * on IOP3XX to avoid data corruption on the bus.
+ * on IOP3XX to avoid data corruption on the bus. We use the
+ * gpiod_set_raw_value() to make sure the 0 hits the hardware
+ * GPOD register. These descriptors are only passed along to
+ * the device if this is necessary.
*/
-#if defined(CONFIG_ARCH_IOP32X) || defined(CONFIG_ARCH_IOP33X)
- if (iop3xx_adap->id == 0) {
- gpio_set_value(7, 0);
- gpio_set_value(6, 0);
- } else {
- gpio_set_value(5, 0);
- gpio_set_value(4, 0);
- }
-#endif
+ if (iop3xx_adap->gpio_scl)
+ gpiod_set_raw_value(iop3xx_adap->gpio_scl, 0);
+ if (iop3xx_adap->gpio_sda)
+ gpiod_set_raw_value(iop3xx_adap->gpio_sda, 0);
+
/* NB SR bits not same position as CR IE bits :-( */
iop3xx_adap->SR_enabled =
IOP3XX_ISR_ALD | IOP3XX_ISR_BERRD |
@@ -434,6 +433,17 @@ iop3xx_i2c_probe(struct platform_device *pdev)
goto free_adapter;
}
+ adapter_data->gpio_scl = devm_gpiod_get_optional(&pdev->dev,
+ "scl",
+ GPIOD_ASIS);
+ if (IS_ERR(adapter_data->gpio_scl))
+ return PTR_ERR(adapter_data->gpio_scl);
+ adapter_data->gpio_sda = devm_gpiod_get_optional(&pdev->dev,
+ "sda",
+ GPIOD_ASIS);
+ if (IS_ERR(adapter_data->gpio_sda))
+ return PTR_ERR(adapter_data->gpio_sda);
+
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
ret = -ENODEV;
@@ -98,6 +98,8 @@ struct i2c_algo_iop3xx_data {
spinlock_t lock;
u32 SR_enabled, SR_received;
int id;
+ struct gpio_desc *gpio_scl;
+ struct gpio_desc *gpio_sda;
};
#endif /* I2C_IOP3XX_H */
The IOP3xx has some elaborate code to directly slam the GPIO lines multiplexed with I2C down low before enablement, apparently a workaround for a hardware bug found in the early chips. After consulting the developer documentation for IOP80321 and IOP80331 I can clearly see that this may be useful for IOP80321 family (mach-iop32x) but it is highly dubious for any 80331 series or later chip: in these chips the lines are not multiplexed for UARTs. We convert the code to pass optional GPIO descriptors and register these only on the 80321-based boards where it makes sense, optionally obtain them in the driver and use the gpiod_set_raw_value() to ascertain the line gets driven low when needed. The GPIO driver does not give the GPIO chip a reasonable label so the patch also adds that so that these machine descriptor tables can be used. Cc: arm@kernel.org Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> --- ARM SoC mainatiners: looking for a handshake ACK on this so Wolfram can merge it into the I2C subsystem. Dan Williams: I have seen that you were patching IOP3xx code in 2007, so maybe you remember something about this. --- arch/arm/include/asm/hardware/iop3xx.h | 2 ++ arch/arm/mach-iop32x/em7210.c | 3 +++ arch/arm/mach-iop32x/glantank.c | 3 +++ arch/arm/mach-iop32x/iq31244.c | 3 +++ arch/arm/mach-iop32x/iq80321.c | 3 +++ arch/arm/mach-iop32x/n2100.c | 2 ++ arch/arm/plat-iop/i2c.c | 24 +++++++++++++++++++ drivers/gpio/gpio-iop.c | 1 + drivers/i2c/busses/i2c-iop3xx.c | 32 +++++++++++++++++--------- drivers/i2c/busses/i2c-iop3xx.h | 2 ++ 10 files changed, 64 insertions(+), 11 deletions(-)