Re: [PATCH v1 6/6] i2c: at91: Convert to use struct i2c_timings

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On 25/07/2018 17:39:30+0300, Andy Shevchenko wrote:
> Instead of using custom variables and parser, convert the driver to use
> the ones provided by I2C core.
> 
> No functional change intended.
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Acked-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
Tested-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>

> ---
>  drivers/i2c/busses/i2c-at91.c | 24 ++++++++----------------
>  1 file changed, 8 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-at91.c b/drivers/i2c/busses/i2c-at91.c
> index 3f3e8b3bf5ff..c83caa383cd2 100644
> --- a/drivers/i2c/busses/i2c-at91.c
> +++ b/drivers/i2c/busses/i2c-at91.c
> @@ -34,7 +34,6 @@
>  #include <linux/pm_runtime.h>
>  #include <linux/pinctrl/consumer.h>
>  
> -#define DEFAULT_TWI_CLK_HZ		100000		/* max 400 Kbits/s */
>  #define AT91_I2C_TIMEOUT	msecs_to_jiffies(100)	/* transfer timeout */
>  #define AT91_I2C_DMA_THRESHOLD	8			/* enable DMA if transfer size is bigger than this threshold */
>  #define AUTOSUSPEND_TIMEOUT		2000
> @@ -190,16 +189,18 @@ static void at91_init_twi_bus(struct at91_twi_dev *dev)
>   * Calculate symmetric clock as stated in datasheet:
>   * twi_clk = F_MAIN / (2 * (cdiv * (1 << ckdiv) + offset))
>   */
> -static void at91_calc_twi_clock(struct at91_twi_dev *dev, int twi_clk)
> +static void at91_calc_twi_clock(struct at91_twi_dev *dev)
>  {
>  	int ckdiv, cdiv, div, hold = 0;
>  	struct at91_twi_pdata *pdata = dev->pdata;
>  	int offset = pdata->clk_offset;
>  	int max_ckdiv = pdata->clk_max_div;
> -	u32 twd_hold_time_ns = 0;
> +	struct i2c_timings timings, *t = &timings;
> +
> +	i2c_parse_fw_timings(dev->dev, t, true);
>  
>  	div = max(0, (int)DIV_ROUND_UP(clk_get_rate(dev->clk),
> -				       2 * twi_clk) - offset);
> +				       2 * t->bus_freq_hz) - offset);
>  	ckdiv = fls(div >> 8);
>  	cdiv = div >> ckdiv;
>  
> @@ -211,15 +212,12 @@ static void at91_calc_twi_clock(struct at91_twi_dev *dev, int twi_clk)
>  	}
>  
>  	if (pdata->has_hold_field) {
> -		of_property_read_u32(dev->dev->of_node, "i2c-sda-hold-time-ns",
> -				     &twd_hold_time_ns);
> -
>  		/*
>  		 * hold time = HOLD + 3 x T_peripheral_clock
>  		 * Use clk rate in kHz to prevent overflows when computing
>  		 * hold.
>  		 */
> -		hold = DIV_ROUND_UP(twd_hold_time_ns
> +		hold = DIV_ROUND_UP(t->sda_hold_ns
>  				    * (clk_get_rate(dev->clk) / 1000), 1000000);
>  		hold -= 3;
>  		if (hold < 0)
> @@ -236,7 +234,7 @@ static void at91_calc_twi_clock(struct at91_twi_dev *dev, int twi_clk)
>  			    | AT91_TWI_CWGR_HOLD(hold);
>  
>  	dev_dbg(dev->dev, "cdiv %d ckdiv %d hold %d (%d ns)\n",
> -		cdiv, ckdiv, hold, twd_hold_time_ns);
> +		cdiv, ckdiv, hold, t->sda_hold_ns);
>  }
>  
>  static void at91_twi_dma_cleanup(struct at91_twi_dev *dev)
> @@ -1052,7 +1050,6 @@ static int at91_twi_probe(struct platform_device *pdev)
>  	struct resource *mem;
>  	int rc;
>  	u32 phy_addr;
> -	u32 bus_clk_rate;
>  
>  	dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
>  	if (!dev)
> @@ -1108,12 +1105,7 @@ static int at91_twi_probe(struct platform_device *pdev)
>  		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_calc_twi_clock(dev);
>  	at91_init_twi_bus(dev);
>  
>  	snprintf(dev->adapter.name, sizeof(dev->adapter.name), "AT91");
> -- 
> 2.18.0
> 

-- 
Alexandre Belloni, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com



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