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SubjectRe: [PATCH 4/6] i2c: designware: Detect the FIFO size in the common code
On Fri, Mar 06, 2020 at 04:19:54PM +0300, Sergey.Semin@baikalelectronics.ru wrote:
> From: Serge Semin <Sergey.Semin@baikalelectronics.ru>
>
> The problem with detecting the FIFO depth in the platform driver
> is that in order to implement this we have to access the controller
> IC_COMP_PARAM_1 register. Currently it's done before the
> i2c_dw_set_reg_access() method execution, which is errors prone since
> the method determines the registers endianness and access mode and we
> can't use dw_readl/dw_writel accessors before this information is
> retrieved. We also can't move the i2c_dw_set_reg_access() function
> invocation to after the master/slave probe functions call (when endianness
> and access mode are determined), since the FIFO depth information is used
> by them for initializations. So in order to fix the problem we have no
> choice but to move the FIFO size detection methods to the common code and
> call it at the probe stage.

Sounds reasonable.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

> Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
> Signed-off-by: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
> Cc: Paul Burton <paulburton@kernel.org>
> Cc: Ralf Baechle <ralf@linux-mips.org>
> Cc: linux-i2c@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> ---
> drivers/i2c/busses/i2c-designware-common.c | 22 +++++++++++++++++++
> drivers/i2c/busses/i2c-designware-core.h | 1 +
> drivers/i2c/busses/i2c-designware-master.c | 2 ++
> drivers/i2c/busses/i2c-designware-platdrv.c | 24 ---------------------
> drivers/i2c/busses/i2c-designware-slave.c | 2 ++
> 5 files changed, 27 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-designware-common.c b/drivers/i2c/busses/i2c-designware-common.c
> index 2de7452fcd6d..4291ff6246d8 100644
> --- a/drivers/i2c/busses/i2c-designware-common.c
> +++ b/drivers/i2c/busses/i2c-designware-common.c
> @@ -344,6 +344,28 @@ int i2c_dw_handle_tx_abort(struct dw_i2c_dev *dev)
> return -EIO;
> }
>
> +void i2c_dw_set_fifo_size(struct dw_i2c_dev *dev)
> +{
> + u32 param, tx_fifo_depth, rx_fifo_depth;
> +
> + /*
> + * Try to detect the FIFO depth if not set by interface driver,
> + * the depth could be from 2 to 256 from HW spec.
> + */
> + param = dw_readl(dev, DW_IC_COMP_PARAM_1);
> + tx_fifo_depth = ((param >> 16) & 0xff) + 1;
> + rx_fifo_depth = ((param >> 8) & 0xff) + 1;
> + if (!dev->tx_fifo_depth) {
> + dev->tx_fifo_depth = tx_fifo_depth;
> + dev->rx_fifo_depth = rx_fifo_depth;
> + } else if (tx_fifo_depth >= 2) {
> + dev->tx_fifo_depth = min_t(u32, dev->tx_fifo_depth,
> + tx_fifo_depth);
> + dev->rx_fifo_depth = min_t(u32, dev->rx_fifo_depth,
> + rx_fifo_depth);
> + }
> +}
> +
> u32 i2c_dw_func(struct i2c_adapter *adap)
> {
> struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
> diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
> index 67edbbde1070..3fbc9f22fcf1 100644
> --- a/drivers/i2c/busses/i2c-designware-core.h
> +++ b/drivers/i2c/busses/i2c-designware-core.h
> @@ -297,6 +297,7 @@ int i2c_dw_acquire_lock(struct dw_i2c_dev *dev);
> void i2c_dw_release_lock(struct dw_i2c_dev *dev);
> int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev);
> int i2c_dw_handle_tx_abort(struct dw_i2c_dev *dev);
> +void i2c_dw_set_fifo_size(struct dw_i2c_dev *dev);
> u32 i2c_dw_func(struct i2c_adapter *adap);
> void i2c_dw_disable(struct dw_i2c_dev *dev);
> void i2c_dw_disable_int(struct dw_i2c_dev *dev);
> diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c
> index e8b328242256..05da900cf375 100644
> --- a/drivers/i2c/busses/i2c-designware-master.c
> +++ b/drivers/i2c/busses/i2c-designware-master.c
> @@ -698,6 +698,8 @@ int i2c_dw_probe(struct dw_i2c_dev *dev)
> if (ret)
> return ret;
>
> + i2c_dw_set_fifo_size(dev);
> +
> ret = dev->init(dev);
> if (ret)
> return ret;
> diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
> index 3b7d58c2fe85..cb494273bb60 100644
> --- a/drivers/i2c/busses/i2c-designware-platdrv.c
> +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
> @@ -219,28 +219,6 @@ static void i2c_dw_configure_slave(struct dw_i2c_dev *dev)
> dev->mode = DW_IC_SLAVE;
> }
>
> -static void dw_i2c_set_fifo_size(struct dw_i2c_dev *dev)
> -{
> - u32 param, tx_fifo_depth, rx_fifo_depth;
> -
> - /*
> - * Try to detect the FIFO depth if not set by interface driver,
> - * the depth could be from 2 to 256 from HW spec.
> - */
> - param = i2c_dw_read_comp_param(dev);
> - tx_fifo_depth = ((param >> 16) & 0xff) + 1;
> - rx_fifo_depth = ((param >> 8) & 0xff) + 1;
> - if (!dev->tx_fifo_depth) {
> - dev->tx_fifo_depth = tx_fifo_depth;
> - dev->rx_fifo_depth = rx_fifo_depth;
> - } else if (tx_fifo_depth >= 2) {
> - dev->tx_fifo_depth = min_t(u32, dev->tx_fifo_depth,
> - tx_fifo_depth);
> - dev->rx_fifo_depth = min_t(u32, dev->rx_fifo_depth,
> - rx_fifo_depth);
> - }
> -}
> -
> static void dw_i2c_plat_pm_cleanup(struct dw_i2c_dev *dev)
> {
> pm_runtime_disable(dev->dev);
> @@ -362,8 +340,6 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
> div_u64(clk_khz * t->sda_hold_ns + 500000, 1000000);
> }
>
> - dw_i2c_set_fifo_size(dev);
> -
> adap = &dev->adapter;
> adap->owner = THIS_MODULE;
> adap->class = I2C_CLASS_DEPRECATED;
> diff --git a/drivers/i2c/busses/i2c-designware-slave.c b/drivers/i2c/busses/i2c-designware-slave.c
> index f5f001738df5..0fc3aa31d46a 100644
> --- a/drivers/i2c/busses/i2c-designware-slave.c
> +++ b/drivers/i2c/busses/i2c-designware-slave.c
> @@ -260,6 +260,8 @@ int i2c_dw_probe_slave(struct dw_i2c_dev *dev)
> if (ret)
> return ret;
>
> + i2c_dw_set_fifo_size(dev);
> +
> ret = dev->init(dev);
> if (ret)
> return ret;
> --
> 2.25.1
>

--
With Best Regards,
Andy Shevchenko


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