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Date: Tue, 31 Oct 2017 16:03:04 +0100
From: Ludovic Desroches <ludovic.desroches@...rochip.com>
To: Juergen Fitschen <me@....yt>
CC: Ludovic Desroches <ludovic.desroches@...rochip.com>,
Wolfram Sang <wsa@...-dreams.de>, <linux-i2c@...r.kernel.org>,
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH RFC 1/4] i2c: at91: segregate master mode specific code
from probe and init func
On Fri, Oct 27, 2017 at 05:11:20PM +0200, Juergen Fitschen wrote:
> In order to implement slave mode support for the at91 hardware we have to
> segregate all master mode specific function parts from the general parts.
> The upcoming slave mode patch will call its sepcific probe resp. init
> function instead of the master mode functions after the shared general
> code has been executed.
>
> This concept has been influenced by the i2c-designware driver.
>
> Signed-off-by: Juergen Fitschen <me@....yt>
Acked-by: Ludovic Desroches <ludovic.desroches@...rochip.com>
> ---
> drivers/i2c/busses/i2c-at91.c | 90 ++++++++++++++++++++++++++-----------------
> 1 file changed, 55 insertions(+), 35 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-at91.c b/drivers/i2c/busses/i2c-at91.c
> index bfd1fdf..73b6582 100644
> --- a/drivers/i2c/busses/i2c-at91.c
> +++ b/drivers/i2c/busses/i2c-at91.c
> @@ -174,10 +174,8 @@ static void at91_twi_irq_restore(struct at91_twi_dev *dev)
> at91_twi_write(dev, AT91_TWI_IER, dev->imr);
> }
>
> -static void at91_init_twi_bus(struct at91_twi_dev *dev)
> +static void at91_init_twi_bus_master(struct at91_twi_dev *dev)
> {
> - at91_disable_twi_interrupts(dev);
> - at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_SWRST);
> /* FIFO should be enabled immediately after the software reset */
> if (dev->fifo_size)
> at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_FIFOEN);
> @@ -186,6 +184,14 @@ static void at91_init_twi_bus(struct at91_twi_dev *dev)
> at91_twi_write(dev, AT91_TWI_CWGR, dev->twi_cwgr_reg);
> }
>
> +static void at91_init_twi_bus(struct at91_twi_dev *dev)
> +{
> + at91_disable_twi_interrupts(dev);
> + at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_SWRST);
> +
> + at91_init_twi_bus_master(dev);
> +}
> +
> /*
> * Calculate symmetric clock as stated in datasheet:
> * twi_clk = F_MAIN / (2 * (cdiv * (1 << ckdiv) + offset))
> @@ -1038,18 +1044,56 @@ static struct at91_twi_pdata *at91_twi_get_driver_data(
> return (struct at91_twi_pdata *) platform_get_device_id(pdev)->driver_data;
> }
>
> +static int at91_twi_probe_master(struct platform_device *pdev,
> + u32 phy_addr, struct at91_twi_dev *dev)
> +{
> + int rc;
> + u32 bus_clk_rate;
> +
> + init_completion(&dev->cmd_complete);
> +
> + rc = devm_request_irq(&pdev->dev, dev->irq, atmel_twi_interrupt, 0,
> + dev_name(dev->dev), dev);
> + if (rc) {
> + dev_err(dev->dev, "Cannot get irq %d: %d\n", dev->irq, rc);
> + return rc;
> + }
> +
> + if (dev->dev->of_node) {
> + rc = at91_twi_configure_dma(dev, phy_addr);
> + if (rc == -EPROBE_DEFER)
> + return rc;
> + }
> +
> + if (!of_property_read_u32(pdev->dev.of_node, "atmel,fifo-size",
> + &dev->fifo_size)) {
> + dev_info(dev->dev, "Using FIFO (%u data)\n", dev->fifo_size);
> + }
> +
> + rc = of_property_read_u32(dev->dev->of_node, "clock-frequency",
> + &bus_clk_rate);
> + if (rc)
> + bus_clk_rate = DEFAULT_TWI_CLK_HZ;
> +
> + at91_calc_twi_clock(dev, bus_clk_rate);
> +
> + dev->adapter.algo = &at91_twi_algorithm;
> + dev->adapter.quirks = &at91_twi_quirks;
> +
> + return 0;
> +}
> +
> static int at91_twi_probe(struct platform_device *pdev)
> {
> struct at91_twi_dev *dev;
> struct resource *mem;
> int rc;
> u32 phy_addr;
> - u32 bus_clk_rate;
>
> dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
> if (!dev)
> return -ENOMEM;
> - init_completion(&dev->cmd_complete);
> +
> dev->dev = &pdev->dev;
>
> mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> @@ -1069,13 +1113,6 @@ static int at91_twi_probe(struct platform_device *pdev)
> if (dev->irq < 0)
> return dev->irq;
>
> - rc = devm_request_irq(&pdev->dev, dev->irq, atmel_twi_interrupt, 0,
> - dev_name(dev->dev), dev);
> - if (rc) {
> - dev_err(dev->dev, "Cannot get irq %d: %d\n", dev->irq, rc);
> - return rc;
> - }
> -
> platform_set_drvdata(pdev, dev);
>
> dev->clk = devm_clk_get(dev->dev, NULL);
> @@ -1087,38 +1124,21 @@ static int at91_twi_probe(struct platform_device *pdev)
> if (rc)
> return rc;
>
> - if (dev->dev->of_node) {
> - rc = at91_twi_configure_dma(dev, phy_addr);
> - if (rc == -EPROBE_DEFER) {
> - clk_disable_unprepare(dev->clk);
> - return rc;
> - }
> - }
> -
> - if (!of_property_read_u32(pdev->dev.of_node, "atmel,fifo-size",
> - &dev->fifo_size)) {
> - dev_info(dev->dev, "Using FIFO (%u data)\n", dev->fifo_size);
> - }
> -
> - rc = of_property_read_u32(dev->dev->of_node, "clock-frequency",
> - &bus_clk_rate);
> - if (rc)
> - bus_clk_rate = DEFAULT_TWI_CLK_HZ;
> -
> - at91_calc_twi_clock(dev, bus_clk_rate);
> - at91_init_twi_bus(dev);
> -
> snprintf(dev->adapter.name, sizeof(dev->adapter.name), "AT91");
> i2c_set_adapdata(&dev->adapter, dev);
> dev->adapter.owner = THIS_MODULE;
> dev->adapter.class = I2C_CLASS_DEPRECATED;
> - dev->adapter.algo = &at91_twi_algorithm;
> - dev->adapter.quirks = &at91_twi_quirks;
> dev->adapter.dev.parent = dev->dev;
> dev->adapter.nr = pdev->id;
> dev->adapter.timeout = AT91_I2C_TIMEOUT;
> dev->adapter.dev.of_node = pdev->dev.of_node;
>
> + rc = at91_twi_probe_master(pdev, phy_addr, dev);
> + if (rc)
> + return rc;
> +
> + at91_init_twi_bus(dev);
> +
> pm_runtime_set_autosuspend_delay(dev->dev, AUTOSUSPEND_TIMEOUT);
> pm_runtime_use_autosuspend(dev->dev);
> pm_runtime_set_active(dev->dev);
> --
> 2.7.4
>
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