From fdb7e884ad617f8aa69abdd7f39e3fdac85e081e Mon Sep 17 00:00:00 2001 From: Linus Walleij Date: Sat, 1 Jun 2019 00:37:56 +0200 Subject: [PATCH] i2c: iop: Use GPIO descriptors 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. Signed-off-by: Linus Walleij Acked-by: Arnd Bergmann Acked-by: Dan Williams Signed-off-by: Wolfram Sang --- 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(-) diff --git a/arch/arm/include/asm/hardware/iop3xx.h b/arch/arm/include/asm/hardware/iop3xx.h index 2594a95ff19a..a15d08160e8f 100644 --- a/arch/arm/include/asm/hardware/iop3xx.h +++ b/arch/arm/include/asm/hardware/iop3xx.h @@ -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 diff --git a/arch/arm/mach-iop32x/em7210.c b/arch/arm/mach-iop32x/em7210.c index 77e1ff057303..d2bcbac6b7f2 100644 --- a/arch/arm/mach-iop32x/em7210.c +++ b/arch/arm/mach-iop32x/em7210.c @@ -24,6 +24,7 @@ #include #include #include +#include #include #include #include @@ -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); diff --git a/arch/arm/mach-iop32x/glantank.c b/arch/arm/mach-iop32x/glantank.c index 547b2342d61a..4c4995007d17 100644 --- a/arch/arm/mach-iop32x/glantank.c +++ b/arch/arm/mach-iop32x/glantank.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #include #include @@ -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); diff --git a/arch/arm/mach-iop32x/iq31244.c b/arch/arm/mach-iop32x/iq31244.c index 0e1392b20d18..56a64ffd3824 100644 --- a/arch/arm/mach-iop32x/iq31244.c +++ b/arch/arm/mach-iop32x/iq31244.c @@ -26,6 +26,7 @@ #include #include #include +#include #include #include #include @@ -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); diff --git a/arch/arm/mach-iop32x/iq80321.c b/arch/arm/mach-iop32x/iq80321.c index 66782ff1f46a..02abbf9efd54 100644 --- a/arch/arm/mach-iop32x/iq80321.c +++ b/arch/arm/mach-iop32x/iq80321.c @@ -23,6 +23,7 @@ #include #include #include +#include #include #include #include @@ -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); diff --git a/arch/arm/mach-iop32x/n2100.c b/arch/arm/mach-iop32x/n2100.c index 23e8c93515d4..c780b6e82ad9 100644 --- a/arch/arm/mach-iop32x/n2100.c +++ b/arch/arm/mach-iop32x/n2100.c @@ -31,6 +31,7 @@ #include #include #include +#include #include #include #include @@ -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); diff --git a/arch/arm/plat-iop/i2c.c b/arch/arm/plat-iop/i2c.c index 88215ad031a2..bac20f7f5f8a 100644 --- a/arch/arm/plat-iop/i2c.c +++ b/arch/arm/plat-iop/i2c.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include #include @@ -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, diff --git a/drivers/gpio/gpio-iop.c b/drivers/gpio/gpio-iop.c index 11b77d868c89..e9546d6c7451 100644 --- a/drivers/gpio/gpio-iop.c +++ b/drivers/gpio/gpio-iop.c @@ -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); } diff --git a/drivers/i2c/busses/i2c-iop3xx.c b/drivers/i2c/busses/i2c-iop3xx.c index a34cb3848280..eafc1a4d8656 100644 --- a/drivers/i2c/busses/i2c-iop3xx.c +++ b/drivers/i2c/busses/i2c-iop3xx.c @@ -38,7 +38,7 @@ #include #include #include -#include +#include #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; diff --git a/drivers/i2c/busses/i2c-iop3xx.h b/drivers/i2c/busses/i2c-iop3xx.h index 2d6929c2bd92..231897838386 100644 --- a/drivers/i2c/busses/i2c-iop3xx.h +++ b/drivers/i2c/busses/i2c-iop3xx.h @@ -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 */ -- 2.20.1