On Thu, Sep 25, 2008 at 10:53:49AM +0300, Tony Lindgren wrote:
> From: Syed Mohammed Khasim <x0khasim@xxxxxx>
>
> Omap2430 has additional support for high-speed I2C.
>
> This patch moves I2C speed parameter (from module) to platform data.
> Also added basic High Speed support based on I2C bus speed.
>
> This patch is tested for high speed I2C (with TWL4030 Keypad) and works as
> expected.
>
> Signed-off-by: Syed Mohammed Khasim <x0khasim@xxxxxx>
> Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-omap.c | 111 +++++++++++++++++++++++++++++-----------
> 1 files changed, 80 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
> index a06ad42..0d30790 100644
> --- a/drivers/i2c/busses/i2c-omap.c
> +++ b/drivers/i2c/busses/i2c-omap.c
> @@ -83,6 +83,7 @@
> /* I2C Configuration Register (OMAP_I2C_CON): */
> #define OMAP_I2C_CON_EN (1 << 15) /* I2C module enable */
> #define OMAP_I2C_CON_BE (1 << 14) /* Big endian mode */
> +#define OMAP_I2C_CON_OPMODE (1 << 12) /* High Speed support */
> #define OMAP_I2C_CON_STB (1 << 11) /* Start byte mode (master) */
> #define OMAP_I2C_CON_MST (1 << 10) /* Master/slave mode */
> #define OMAP_I2C_CON_TRX (1 << 9) /* TX/RX mode (master only) */
> @@ -91,6 +92,10 @@
> #define OMAP_I2C_CON_STP (1 << 1) /* Stop cond (master only) */
> #define OMAP_I2C_CON_STT (1 << 0) /* Start condition (master) */
>
> +/* I2C SCL time value when Master */
> +#define OMAP_I2C_SCLL_HSSCLL 8
> +#define OMAP_I2C_SCLH_HSSCLH 8
> +
> /* I2C System Test Register (OMAP_I2C_SYSTEST): */
> #ifdef DEBUG
> #define OMAP_I2C_SYSTEST_ST_EN (1 << 15) /* System test enable */
> @@ -109,12 +114,6 @@
> /* I2C System Configuration Register (OMAP_I2C_SYSC): */
> #define OMAP_I2C_SYSC_SRST (1 << 1) /* Soft Reset */
>
> -/* REVISIT: Use platform_data instead of module parameters */
> -/* Fast Mode = 400 kHz, Standard = 100 kHz */
> -static int clock = 100; /* Default: 100 kHz */
> -module_param(clock, int, 0);
> -MODULE_PARM_DESC(clock, "Set I2C clock in kHz: 400=fast mode (default == 100)");
> -
> struct omap_i2c_dev {
> struct device *dev;
> void __iomem *base; /* virtual */
> @@ -123,6 +122,7 @@ struct omap_i2c_dev {
> struct clk *fclk; /* Functional clock */
> struct completion cmd_complete;
> struct resource *ioarea;
> + u32 speed; /* Speed of bus in Khz */
> u16 cmd_err;
> u8 *buf;
> size_t buf_len;
> @@ -152,17 +152,28 @@ static int omap_i2c_get_clocks(struct omap_i2c_dev *dev)
> return -ENODEV;
> }
> }
> -
> - dev->fclk = clk_get(dev->dev, "i2c_fck");
> - if (IS_ERR(dev->fclk)) {
> - if (dev->iclk != NULL) {
> - clk_put(dev->iclk);
> - dev->iclk = NULL;
> + /* For I2C operations on 2430 we need 96Mhz clock */
> + if (cpu_is_omap2430()) {
> + dev->fclk = clk_get(dev->dev, "i2chs_fck");
> + if (IS_ERR(dev->fclk)) {
> + if (dev->iclk != NULL) {
> + clk_put(dev->iclk);
> + dev->iclk = NULL;
> + }
I'm sorry, but I think this is mis-use of the clock system. The
actual name of the clock should be provided for the driver, not
the driver having to search for different clocks.
> + dev->fclk = NULL;
> + return -ENODEV;
> + }
> + } else {
> + dev->fclk = clk_get(dev->dev, "i2c_fck");
> + if (IS_ERR(dev->fclk)) {
> + if (dev->iclk != NULL) {
> + clk_put(dev->iclk);
> + dev->iclk = NULL;
> + }
> + dev->fclk = NULL;
> + return -ENODEV;
> }
> - dev->fclk = NULL;
> - return -ENODEV;
> }
> -
> return 0;
> }
>
> @@ -210,9 +221,11 @@ static void omap_i2c_idle(struct omap_i2c_dev *dev)
>
> static int omap_i2c_init(struct omap_i2c_dev *dev)
> {
> - u16 psc = 0;
> + u16 psc = 0, scll = 0, sclh = 0;
> + u16 fsscll = 0, fssclh = 0, hsscll = 0, hssclh = 0;
> unsigned long fclk_rate = 12000000;
> unsigned long timeout;
> + unsigned long internal_clk = 0;
>
> if (!dev->rev1) {
> omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG, OMAP_I2C_SYSC_SRST);
> @@ -255,18 +268,47 @@ static int omap_i2c_init(struct omap_i2c_dev *dev)
> psc = fclk_rate / 12000000;
> }
>
> + if (cpu_is_omap2430()) {
> +
> + /* HSI2C controller internal clk rate should be 19.2 Mhz */
> + internal_clk = 19200;
> + fclk_rate = clk_get_rate(dev->fclk) / 1000;
> +
> + /* Compute prescaler divisor */
> + psc = fclk_rate / internal_clk;
> + psc = psc - 1;
> +
> + /* If configured for High Speed */
> + if (dev->speed > 400) {
> + /* For first phase of HS mode */
> + fsscll = internal_clk / (400 * 2) - 6;
> + fssclh = internal_clk / (400 * 2) - 6;
> +
> + /* For second phase of HS mode */
> + hsscll = fclk_rate / (dev->speed * 2) - 6;
> + hssclh = fclk_rate / (dev->speed * 2) - 6;
> + } else {
> + /* To handle F/S modes */
> + fsscll = internal_clk / (dev->speed * 2) - 6;
> + fssclh = internal_clk / (dev->speed * 2) - 6;
> + }
> + scll = (hsscll << OMAP_I2C_SCLL_HSSCLL) | fsscll;
> + sclh = (hssclh << OMAP_I2C_SCLH_HSSCLH) | fssclh;
> + } else {
> + /* Program desired operating rate */
> + fclk_rate /= (psc + 1) * 1000;
> + if (psc > 2)
> + psc = 2;
> + scll = fclk_rate / (dev->speed * 2) - 7 + psc;
> + sclh = fclk_rate / (dev->speed * 2) - 7 + psc;
> + }
> +
> /* Setup clock prescaler to obtain approx 12MHz I2C module clock: */
> omap_i2c_write_reg(dev, OMAP_I2C_PSC_REG, psc);
>
> - /* Program desired operating rate */
> - fclk_rate /= (psc + 1) * 1000;
> - if (psc > 2)
> - psc = 2;
> -
> - omap_i2c_write_reg(dev, OMAP_I2C_SCLL_REG,
> - fclk_rate / (clock * 2) - 7 + psc);
> - omap_i2c_write_reg(dev, OMAP_I2C_SCLH_REG,
> - fclk_rate / (clock * 2) - 7 + psc);
> + /* SCL low and high time values */
> + omap_i2c_write_reg(dev, OMAP_I2C_SCLL_REG, scll);
> + omap_i2c_write_reg(dev, OMAP_I2C_SCLH_REG, sclh);
>
> /* Take the I2C module out of reset: */
> omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
> @@ -326,6 +368,11 @@ static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
> dev->cmd_err = 0;
>
> w = OMAP_I2C_CON_EN | OMAP_I2C_CON_MST | OMAP_I2C_CON_STT;
> +
> + /* High speed configuration */
> + if (dev->speed > 400)
> + w |= OMAP_I2C_CON_OPMODE;
> +
> if (msg->flags & I2C_M_TEN)
> w |= OMAP_I2C_CON_XA;
> if (!(msg->flags & I2C_M_RD))
> @@ -562,6 +609,7 @@ omap_i2c_probe(struct platform_device *pdev)
> struct i2c_adapter *adap;
> struct resource *mem, *irq, *ioarea;
> int r;
> + u32 *speed = NULL;
>
> /* NOTE: driver uses the static register mapping */
> mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> @@ -582,17 +630,18 @@ omap_i2c_probe(struct platform_device *pdev)
> return -EBUSY;
> }
>
> - if (clock > 200)
> - clock = 400; /* Fast mode */
> - else
> - clock = 100; /* Standard mode */
> -
> dev = kzalloc(sizeof(struct omap_i2c_dev), GFP_KERNEL);
> if (!dev) {
> r = -ENOMEM;
> goto err_release_region;
> }
>
> + if (pdev->dev.platform_data != NULL)
> + speed = (u32 *) pdev->dev.platform_data;
> + else
> + *speed = 100; /* Defualt speed */
> +
> + dev->speed = *speed;
> dev->dev = &pdev->dev;
> dev->irq = irq->start;
> dev->base = (void __iomem *) IO_ADDRESS(mem->start);
> @@ -618,7 +667,7 @@ omap_i2c_probe(struct platform_device *pdev)
> }
> r = omap_i2c_read_reg(dev, OMAP_I2C_REV_REG) & 0xff;
> dev_info(dev->dev, "bus %d rev%d.%d at %d kHz\n",
> - pdev->id, r >> 4, r & 0xf, clock);
> + pdev->id, r >> 4, r & 0xf, dev->speed);
>
> adap = &dev->adapter;
> i2c_set_adapdata(adap, dev);
> --
> 1.5.6.rc3.21.g8c6b5
>
>
> _______________________________________________
> i2c mailing list
> i2c@xxxxxxxxxxxxxx
> http://lists.lm-sensors.org/mailman/listinfo/i2c
--
Ben (ben@xxxxxxxxx, http://www.fluff.org/)
'a smiley only costs 4 bytes'
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
