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Date: Sat, 18 Aug 2012 14:47:03 +0200
From: Wolfram Sang <w.sang@...gutronix.de>
To: Laxman Dewangan <ldewangan@...dia.com>
Cc: khali@...ux-fr.org, swarren@...dia.com, linux-i2c@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-tegra@...r.kernel.org,
olof@...om.net
Subject: Re: [PATCH REBASE 1/2] i2c: tegra: I2_M_NOSTART functionality not
supported in Tegra20
On Sat, Aug 18, 2012 at 12:32:34AM +0530, Laxman Dewangan wrote:
> Tegra20 i2c controller does not support the continue transfer
> which implements the I2C_M_NOSTART functionality of i2c
> protocol mangling.
> Removing the I2C_M_NOSTART functionality for Tegra20.
>
> Signed-off-by: Laxman Dewangan <ldewangan@...dia.com>
> ---
> This is rebased on linux-next-20120816.
>
> drivers/i2c/busses/i2c-tegra.c | 73 +++++++++++++++++++++++++++++++--------
> 1 files changed, 58 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
> index 7149625..554f713 100644
> --- a/drivers/i2c/busses/i2c-tegra.c
> +++ b/drivers/i2c/busses/i2c-tegra.c
> @@ -27,6 +27,7 @@
> #include <linux/slab.h>
> #include <linux/i2c-tegra.h>
> #include <linux/of_i2c.h>
> +#include <linux/of_device.h>
> #include <linux/module.h>
>
> #include <asm/unaligned.h>
> @@ -114,6 +115,15 @@ enum msg_end_type {
> };
>
> /**
> + * struct tegra_i2c_hw_feature : Different HW support on Tegra
> + * @has_continue_xfer_support: Continue transfer supports.
> + */
> +
> +struct tegra_i2c_hw_feature {
> + bool has_continue_xfer_support;
> +};
> +
> +/**
> * struct tegra_i2c_dev - per device i2c context
> * @dev: device reference for power management
> * @adapter: core i2c layer adapter information
> @@ -148,6 +158,7 @@ struct tegra_i2c_dev {
> int msg_read;
> unsigned long bus_clk_rate;
> bool is_suspended;
> + bool has_continue_xfer_support;
I wonder if it makes sense to carry a pointer here to the
tegra_i2c_hw_feature in use instead of copying all entries by hand,
since they might get more and more.
> };
>
> static void dvc_writel(struct tegra_i2c_dev *i2c_dev, u32 val, unsigned long reg)
> @@ -563,7 +574,17 @@ static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
> if (i2c_dev->is_suspended)
> return -EBUSY;
>
> - clk_prepare_enable(i2c_dev->div_clk);
> + /* Support I2C_M_NOSTART only if HW support continue xfer. */
> + for (i = 0; i < num - 1; i++) {
> + if ((msgs[i + 1].flags & I2C_M_NOSTART) &&
> + !i2c_dev->has_continue_xfer_support) {
> + dev_err(i2c_dev->dev,
> + "mesg %d have illegal flag\n", i + 1);
> + return -EINVAL;
> + }
> + }
Drivers are requested to explicitly check for features of the I2C bus
(like M_NOSTART) before using them, so I'd skip this extra check.
> +
> + clk_prepare_enable(i2c_dev->clk);
From a glimpse, this change looks unrelated at least. Even wrong, no?
> for (i = 0; i < num; i++) {
> enum msg_end_type end_type = MSG_END_STOP;
> if (i < (num - 1)) {
> @@ -582,8 +603,13 @@ static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
>
> static u32 tegra_i2c_func(struct i2c_adapter *adap)
> {
> - return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR |
> - I2C_FUNC_PROTOCOL_MANGLING | I2C_FUNC_NOSTART;
> + struct tegra_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
> + u32 ret = I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR |
> + I2C_FUNC_PROTOCOL_MANGLING;
> +
> + if (i2c_dev->has_continue_xfer_support)
> + ret |= I2C_FUNC_NOSTART;
> + return ret;
> }
>
> static const struct i2c_algorithm tegra_i2c_algo = {
> @@ -591,6 +617,25 @@ static const struct i2c_algorithm tegra_i2c_algo = {
> .functionality = tegra_i2c_func,
> };
>
> +static struct tegra_i2c_hw_feature tegra20_i2c_hw = {
> + .has_continue_xfer_support = false,
> +};
> +
> +static struct tegra_i2c_hw_feature tegra30_i2c_hw = {
> + .has_continue_xfer_support = true,
> +};
> +
> +#if defined(CONFIG_OF)
> +/* Match table for of_platform binding */
> +static const struct of_device_id tegra_i2c_of_match[] __devinitconst = {
> + { .compatible = "nvidia,tegra30-i2c", .data = &tegra30_i2c_hw, },
> + { .compatible = "nvidia,tegra20-i2c", .data = &tegra20_i2c_hw, },
> + { .compatible = "nvidia,tegra20-i2c-dvc", .data = &tegra20_i2c_hw, },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, tegra_i2c_of_match);
> +#endif
> +
> static int __devinit tegra_i2c_probe(struct platform_device *pdev)
> {
> struct tegra_i2c_dev *i2c_dev;
> @@ -600,6 +645,7 @@ static int __devinit tegra_i2c_probe(struct platform_device *pdev)
> struct clk *fast_clk;
> const unsigned int *prop;
> void __iomem *base;
> + const struct tegra_i2c_hw_feature *hw = &tegra20_i2c_hw;
> int irq;
> int ret = 0;
>
> @@ -659,11 +705,18 @@ static int __devinit tegra_i2c_probe(struct platform_device *pdev)
> i2c_dev->bus_clk_rate = be32_to_cpup(prop);
> }
>
> - if (pdev->dev.of_node)
> + if (pdev->dev.of_node) {
> + const struct of_device_id *match;
> + match = of_match_device(of_match_ptr(tegra_i2c_of_match),
> + &pdev->dev);
> + hw = match->data;
> i2c_dev->is_dvc = of_device_is_compatible(pdev->dev.of_node,
> "nvidia,tegra20-i2c-dvc");
> - else if (pdev->id == 3)
> + } else if (pdev->id == 3) {
> i2c_dev->is_dvc = 1;
> + }
> +
> + i2c_dev->has_continue_xfer_support = hw->has_continue_xfer_support;
> init_completion(&i2c_dev->msg_complete);
>
> platform_set_drvdata(pdev, i2c_dev);
> @@ -751,16 +804,6 @@ static SIMPLE_DEV_PM_OPS(tegra_i2c_pm, tegra_i2c_suspend, tegra_i2c_resume);
> #define TEGRA_I2C_PM NULL
> #endif
>
> -#if defined(CONFIG_OF)
> -/* Match table for of_platform binding */
> -static const struct of_device_id tegra_i2c_of_match[] __devinitconst = {
> - { .compatible = "nvidia,tegra20-i2c", },
> - { .compatible = "nvidia,tegra20-i2c-dvc", },
> - {},
> -};
> -MODULE_DEVICE_TABLE(of, tegra_i2c_of_match);
> -#endif
> -
> static struct platform_driver tegra_i2c_driver = {
> .probe = tegra_i2c_probe,
> .remove = __devexit_p(tegra_i2c_remove),
Thanks,
Wolfram
--
Pengutronix e.K. | Wolfram Sang |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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