From: Raviteja Narayanam <raviteja.narayanam@xilinx.com> To: <linux-i2c@vger.kernel.org>, <michal.simek@xilinx.com> Cc: <linux-arm-kernel@lists.infradead.org>, <linux-kernel@vger.kernel.org>, <git@xilinx.com>, <marex@denx.de>, Raviteja Narayanam <raviteja.narayanam@xilinx.com> Subject: [PATCH 07/10] i2c: xiic: Switch to Xiic standard mode for i2c-read Date: Mon, 31 May 2021 07:19:45 -0600 [thread overview] Message-ID: <20210531131948.19477-8-raviteja.narayanam@xilinx.com> (raw) In-Reply-To: <20210531131948.19477-1-raviteja.narayanam@xilinx.com> Xilinx I2C IP has two modes of operation, both of which implement I2C transactions. The only difference from sw perspective is the programming sequence for these modes. Dynamic mode -> Simple to program, less number of steps in sequence. Standard mode -> Gives flexibility, more number of steps in sequence. In dynamic mode, during the i2c-read transactions, if there is a delay(> 200us) between the register writes (address & byte count), read transaction fails. On a system with load, this scenario is occurring frequently. To avoid this, switch to standard mode if there is a read request. Added a quirk to identify the IP version effected by this and follow the standard mode. Signed-off-by: Raviteja Narayanam <raviteja.narayanam@xilinx.com> --- drivers/i2c/busses/i2c-xiic.c | 58 +++++++++++++++++++++++++++-------- 1 file changed, 45 insertions(+), 13 deletions(-) diff --git a/drivers/i2c/busses/i2c-xiic.c b/drivers/i2c/busses/i2c-xiic.c index 1a26e5ebfc6c..2f0808249ceb 100644 --- a/drivers/i2c/busses/i2c-xiic.c +++ b/drivers/i2c/busses/i2c-xiic.c @@ -33,6 +33,8 @@ #define DRIVER_NAME "xiic-i2c" +#define DYNAMIC_MODE_READ_BROKEN_BIT BIT(0) + enum xilinx_i2c_state { STATE_DONE, STATE_ERROR, @@ -63,6 +65,7 @@ enum xiic_endian { * @dynamic: Mode of controller * @prev_msg_tx: Previous message is Tx * @smbus_block_read: Flag to handle block read + * @quirks: To hold platform specific bug info */ struct xiic_i2c { struct device *dev; @@ -82,6 +85,11 @@ struct xiic_i2c { bool dynamic; bool prev_msg_tx; bool smbus_block_read; + u32 quirks; +}; + +struct xiic_version_data { + u32 quirks; }; #define XIIC_MSB_OFFSET 0 @@ -1032,6 +1040,7 @@ static int xiic_start_xfer(struct xiic_i2c *i2c) static int xiic_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) { + bool broken_read, max_read_len, smbus_blk_read; struct xiic_i2c *i2c = i2c_get_adapdata(adap); int err, count; @@ -1056,13 +1065,22 @@ static int xiic_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) i2c->prev_msg_tx = false; /* - * Enter standard mode only when read length is > 255 bytes or - * for smbus_block_read transaction + * Scan through nmsgs, use dynamic mode when none of the below three + * conditions occur. We need standard mode even if one condition holds + * true in the entire array of messages in a single transfer. + * If read transaction as dynamic mode is broken for delayed reads + * in xlnx,axi-iic-2.0 / xlnx,xps-iic-2.00.a IP versions. + * If read length is > 255 bytes. + * If smbus_block_read transaction. */ for (count = 0; count < i2c->nmsgs; count++) { - if (((i2c->tx_msg[count].flags & I2C_M_RD) && - i2c->tx_msg[count].len > MAX_READ_LENGTH_DYNAMIC) || - (i2c->tx_msg[count].flags & I2C_M_RECV_LEN)) { + broken_read = (i2c->quirks & DYNAMIC_MODE_READ_BROKEN_BIT) && + (i2c->tx_msg[count].flags & I2C_M_RD); + max_read_len = (i2c->tx_msg[count].flags & I2C_M_RD) && + (i2c->tx_msg[count].len > MAX_READ_LENGTH_DYNAMIC); + smbus_blk_read = (i2c->tx_msg[count].flags & I2C_M_RECV_LEN); + + if (broken_read || max_read_len || smbus_blk_read) { i2c->dynamic = false; break; } @@ -1108,10 +1126,23 @@ static const struct i2c_adapter xiic_adapter = { .algo = &xiic_algorithm, }; +static const struct xiic_version_data xiic_2_00 = { + .quirks = DYNAMIC_MODE_READ_BROKEN_BIT, +}; + +#if defined(CONFIG_OF) +static const struct of_device_id xiic_of_match[] = { + { .compatible = "xlnx,xps-iic-2.00.a", .data = &xiic_2_00 }, + {}, +}; +MODULE_DEVICE_TABLE(of, xiic_of_match); +#endif + static int xiic_i2c_probe(struct platform_device *pdev) { struct xiic_i2c *i2c; struct xiic_i2c_platform_data *pdata; + const struct of_device_id *match; struct resource *res; int ret, irq; u8 i; @@ -1121,6 +1152,13 @@ static int xiic_i2c_probe(struct platform_device *pdev) if (!i2c) return -ENOMEM; + match = of_match_node(xiic_of_match, pdev->dev.of_node); + if (match && match->data) { + const struct xiic_version_data *data = match->data; + + i2c->quirks = data->quirks; + } + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); i2c->base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(i2c->base)) @@ -1201,6 +1239,8 @@ static int xiic_i2c_probe(struct platform_device *pdev) i2c_new_client_device(&i2c->adap, pdata->devices + i); } + dev_info(&pdev->dev, "mmio %08lx irq %d\n", (unsigned long)res->start, irq); + return 0; err_clk_dis: @@ -1232,14 +1272,6 @@ static int xiic_i2c_remove(struct platform_device *pdev) return 0; } -#if defined(CONFIG_OF) -static const struct of_device_id xiic_of_match[] = { - { .compatible = "xlnx,xps-iic-2.00.a", }, - {}, -}; -MODULE_DEVICE_TABLE(of, xiic_of_match); -#endif - static int __maybe_unused xiic_i2c_runtime_suspend(struct device *dev) { struct xiic_i2c *i2c = dev_get_drvdata(dev); -- 2.17.1
WARNING: multiple messages have this Message-ID (diff)
From: Raviteja Narayanam <raviteja.narayanam@xilinx.com> To: <linux-i2c@vger.kernel.org>, <michal.simek@xilinx.com> Cc: <linux-arm-kernel@lists.infradead.org>, <linux-kernel@vger.kernel.org>, <git@xilinx.com>, <marex@denx.de>, Raviteja Narayanam <raviteja.narayanam@xilinx.com> Subject: [PATCH 07/10] i2c: xiic: Switch to Xiic standard mode for i2c-read Date: Mon, 31 May 2021 07:19:45 -0600 [thread overview] Message-ID: <20210531131948.19477-8-raviteja.narayanam@xilinx.com> (raw) In-Reply-To: <20210531131948.19477-1-raviteja.narayanam@xilinx.com> Xilinx I2C IP has two modes of operation, both of which implement I2C transactions. The only difference from sw perspective is the programming sequence for these modes. Dynamic mode -> Simple to program, less number of steps in sequence. Standard mode -> Gives flexibility, more number of steps in sequence. In dynamic mode, during the i2c-read transactions, if there is a delay(> 200us) between the register writes (address & byte count), read transaction fails. On a system with load, this scenario is occurring frequently. To avoid this, switch to standard mode if there is a read request. Added a quirk to identify the IP version effected by this and follow the standard mode. Signed-off-by: Raviteja Narayanam <raviteja.narayanam@xilinx.com> --- drivers/i2c/busses/i2c-xiic.c | 58 +++++++++++++++++++++++++++-------- 1 file changed, 45 insertions(+), 13 deletions(-) diff --git a/drivers/i2c/busses/i2c-xiic.c b/drivers/i2c/busses/i2c-xiic.c index 1a26e5ebfc6c..2f0808249ceb 100644 --- a/drivers/i2c/busses/i2c-xiic.c +++ b/drivers/i2c/busses/i2c-xiic.c @@ -33,6 +33,8 @@ #define DRIVER_NAME "xiic-i2c" +#define DYNAMIC_MODE_READ_BROKEN_BIT BIT(0) + enum xilinx_i2c_state { STATE_DONE, STATE_ERROR, @@ -63,6 +65,7 @@ enum xiic_endian { * @dynamic: Mode of controller * @prev_msg_tx: Previous message is Tx * @smbus_block_read: Flag to handle block read + * @quirks: To hold platform specific bug info */ struct xiic_i2c { struct device *dev; @@ -82,6 +85,11 @@ struct xiic_i2c { bool dynamic; bool prev_msg_tx; bool smbus_block_read; + u32 quirks; +}; + +struct xiic_version_data { + u32 quirks; }; #define XIIC_MSB_OFFSET 0 @@ -1032,6 +1040,7 @@ static int xiic_start_xfer(struct xiic_i2c *i2c) static int xiic_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) { + bool broken_read, max_read_len, smbus_blk_read; struct xiic_i2c *i2c = i2c_get_adapdata(adap); int err, count; @@ -1056,13 +1065,22 @@ static int xiic_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) i2c->prev_msg_tx = false; /* - * Enter standard mode only when read length is > 255 bytes or - * for smbus_block_read transaction + * Scan through nmsgs, use dynamic mode when none of the below three + * conditions occur. We need standard mode even if one condition holds + * true in the entire array of messages in a single transfer. + * If read transaction as dynamic mode is broken for delayed reads + * in xlnx,axi-iic-2.0 / xlnx,xps-iic-2.00.a IP versions. + * If read length is > 255 bytes. + * If smbus_block_read transaction. */ for (count = 0; count < i2c->nmsgs; count++) { - if (((i2c->tx_msg[count].flags & I2C_M_RD) && - i2c->tx_msg[count].len > MAX_READ_LENGTH_DYNAMIC) || - (i2c->tx_msg[count].flags & I2C_M_RECV_LEN)) { + broken_read = (i2c->quirks & DYNAMIC_MODE_READ_BROKEN_BIT) && + (i2c->tx_msg[count].flags & I2C_M_RD); + max_read_len = (i2c->tx_msg[count].flags & I2C_M_RD) && + (i2c->tx_msg[count].len > MAX_READ_LENGTH_DYNAMIC); + smbus_blk_read = (i2c->tx_msg[count].flags & I2C_M_RECV_LEN); + + if (broken_read || max_read_len || smbus_blk_read) { i2c->dynamic = false; break; } @@ -1108,10 +1126,23 @@ static const struct i2c_adapter xiic_adapter = { .algo = &xiic_algorithm, }; +static const struct xiic_version_data xiic_2_00 = { + .quirks = DYNAMIC_MODE_READ_BROKEN_BIT, +}; + +#if defined(CONFIG_OF) +static const struct of_device_id xiic_of_match[] = { + { .compatible = "xlnx,xps-iic-2.00.a", .data = &xiic_2_00 }, + {}, +}; +MODULE_DEVICE_TABLE(of, xiic_of_match); +#endif + static int xiic_i2c_probe(struct platform_device *pdev) { struct xiic_i2c *i2c; struct xiic_i2c_platform_data *pdata; + const struct of_device_id *match; struct resource *res; int ret, irq; u8 i; @@ -1121,6 +1152,13 @@ static int xiic_i2c_probe(struct platform_device *pdev) if (!i2c) return -ENOMEM; + match = of_match_node(xiic_of_match, pdev->dev.of_node); + if (match && match->data) { + const struct xiic_version_data *data = match->data; + + i2c->quirks = data->quirks; + } + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); i2c->base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(i2c->base)) @@ -1201,6 +1239,8 @@ static int xiic_i2c_probe(struct platform_device *pdev) i2c_new_client_device(&i2c->adap, pdata->devices + i); } + dev_info(&pdev->dev, "mmio %08lx irq %d\n", (unsigned long)res->start, irq); + return 0; err_clk_dis: @@ -1232,14 +1272,6 @@ static int xiic_i2c_remove(struct platform_device *pdev) return 0; } -#if defined(CONFIG_OF) -static const struct of_device_id xiic_of_match[] = { - { .compatible = "xlnx,xps-iic-2.00.a", }, - {}, -}; -MODULE_DEVICE_TABLE(of, xiic_of_match); -#endif - static int __maybe_unused xiic_i2c_runtime_suspend(struct device *dev) { struct xiic_i2c *i2c = dev_get_drvdata(dev); -- 2.17.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-05-31 13:29 UTC|newest] Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-05-31 13:19 [PATCH 00/10] i2c: xiic: Add features, bug fixes Raviteja Narayanam 2021-05-31 13:19 ` Raviteja Narayanam 2021-05-31 13:19 ` [PATCH 01/10] i2c: xiic: Fix Tx Interrupt path for grouped messages Raviteja Narayanam 2021-05-31 13:19 ` Raviteja Narayanam 2021-05-31 13:19 ` [PATCH 02/10] i2c: xiic: Add standard mode support for > 255 byte read transfers Raviteja Narayanam 2021-05-31 13:19 ` Raviteja Narayanam 2021-06-02 11:17 ` Marek Vasut 2021-06-02 11:17 ` Marek Vasut 2021-06-03 5:33 ` Raviteja Narayanam 2021-06-03 5:33 ` Raviteja Narayanam 2021-06-03 9:57 ` Marek Vasut 2021-06-03 9:57 ` Marek Vasut 2021-06-08 9:46 ` Raviteja Narayanam 2021-06-08 9:46 ` Raviteja Narayanam 2021-05-31 13:19 ` [PATCH 03/10] i2c: xiic: Fix coding style issues Raviteja Narayanam 2021-05-31 13:19 ` Raviteja Narayanam 2021-05-31 15:49 ` Joe Perches 2021-05-31 15:49 ` Joe Perches 2021-05-31 13:19 ` [PATCH 04/10] i2c: xiic: Add smbus_block_read functionality Raviteja Narayanam 2021-05-31 13:19 ` Raviteja Narayanam 2021-05-31 13:19 ` [PATCH 05/10] i2c: xiic: Return value of xiic_reinit Raviteja Narayanam 2021-05-31 13:19 ` Raviteja Narayanam 2021-05-31 13:19 ` [PATCH 06/10] i2c: xiic: Fix the type check for xiic_wakeup Raviteja Narayanam 2021-05-31 13:19 ` Raviteja Narayanam 2021-05-31 13:19 ` Raviteja Narayanam [this message] 2021-05-31 13:19 ` [PATCH 07/10] i2c: xiic: Switch to Xiic standard mode for i2c-read Raviteja Narayanam 2021-05-31 13:19 ` [PATCH 08/10] i2c: xiic: Remove interrupt enable/disable in Rx path Raviteja Narayanam 2021-05-31 13:19 ` Raviteja Narayanam 2021-05-31 13:19 ` [PATCH 09/10] dt-bindings: i2c: xiic: Add 'xlnx,axi-iic-2.1' to compatible Raviteja Narayanam 2021-05-31 13:19 ` [PATCH 09/10] dt-bindings: i2c: xiic: Add 'xlnx, axi-iic-2.1' " Raviteja Narayanam 2021-05-31 13:19 ` [PATCH 10/10] i2c: xiic: Update compatible with new IP version Raviteja Narayanam 2021-05-31 13:19 ` Raviteja Narayanam
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