Re: [PATCH 2/2] i2c-ocore: support 16 and 32-bit wide registers
From: Wolfram Sang <hidden>
Date: 2012-05-12 14:56:48
Also in:
linux-i2c
On Tue, May 08, 2012 at 06:55:29PM +0530, Jayachandran C wrote:
From: Ganesan Ramalingam <ganesanr-dY08KVG/lbpWk0Htik3J/w@public.gmane.org> Some architectures supports only 16-bit or 32-bit read/write access to their iospace. Add a 'regwidth' platform and OF parameter which specifies the IO width to support these platforms. regwidth can be specified as 1, 2 or 4, and has a default value of 1 if it is unspecified. Signed-off-by: Ganesan Ramalingam <ganesanr-dY08KVG/lbpWk0Htik3J/w@public.gmane.org> Signed-off-by: Jayachandran C <jayachandranc-oSioyQM9ZPnuBjGU1YDckgC/G2K4zDHf@public.gmane.org>
Hmm, this is a generic issue and should not be handled with a driver specific property. CCing devicetree-discuss, maybe there is already a way to handle this? The already existing 'regstep' looks suspicious, too? Can't find any documentation for it. Thanks, Wolfram
quoted hunk
--- drivers/i2c/busses/i2c-ocores.c | 32 ++++++++++++++++++++++++++++++-- include/linux/i2c-ocores.h | 1 + 2 files changed, 31 insertions(+), 2 deletions(-)diff --git a/drivers/i2c/busses/i2c-ocores.c b/drivers/i2c/busses/i2c-ocores.c index ebd2700..1313145 100644 --- a/drivers/i2c/busses/i2c-ocores.c +++ b/drivers/i2c/busses/i2c-ocores.c@@ -19,6 +19,9 @@ * - regstep : size of device registers in bytes * - clock-frequency : frequency of bus clock in Hz * + * Optional properties: + * - regwidth : io register width in bytes (1, 2 or 4) + * Example: * * i2c0: ocores@a0000000 {@@ -27,6 +30,7 @@ * interrupts = <10>; * * regstep = <1>; + * regwidth = <1>; * clock-frequency = <20000000>; * * -- Devices connected on this I2C bus get@@ -60,6 +64,7 @@ struct ocores_i2c { void __iomem *base; int regstep; + int regwidth; wait_queue_head_t wait; struct i2c_adapter adap; struct i2c_msg *msg;@@ -102,12 +107,22 @@ struct ocores_i2c { static inline void oc_setreg(struct ocores_i2c *i2c, int reg, u8 value) { - iowrite8(value, i2c->base + reg * i2c->regstep); + if (i2c->regwidth == 4) + iowrite32(value, i2c->base + reg * i2c->regstep); + else if (i2c->regwidth == 2) + iowrite16(value, i2c->base + reg * i2c->regstep); + else + iowrite8(value, i2c->base + reg * i2c->regstep); } static inline u8 oc_getreg(struct ocores_i2c *i2c, int reg) { - return ioread8(i2c->base + reg * i2c->regstep); + if (i2c->regwidth == 4) + return ioread32(i2c->base + reg * i2c->regstep); + else if (i2c->regwidth == 2) + return ioread16(i2c->base + reg * i2c->regstep); + else + return ioread8(i2c->base + reg * i2c->regstep); } static void ocores_process(struct ocores_i2c *i2c)@@ -267,6 +282,10 @@ static int ocores_i2c_of_probe(struct platform_device* pdev, } i2c->clock_khz = be32_to_cpup(val) / 1000; + val = of_get_property(pdev->dev.of_node, "regwidth", NULL); + if (val) + i2c->regwidth = be32_to_cpup(val); + return 0; } #else@@ -309,12 +328,21 @@ static int __devinit ocores_i2c_probe(struct platform_device *pdev) pdata = pdev->dev.platform_data; if (pdata) { i2c->regstep = pdata->regstep; + i2c->regwidth = pdata->regwidth; i2c->clock_khz = pdata->clock_khz; } else { ret = ocores_i2c_of_probe(pdev, i2c); if (ret) return ret; } + if (i2c->regwidth == 0) + i2c->regwidth = 1; /* not configured, use default */ + else if (i2c->regwidth != 1 && i2c->regwidth != 2 && + i2c->regwidth != 4) { + dev_err(&pdev->dev, "Invalid register width %d\n", + i2c->regwidth); + return -EINVAL; + } ocores_init(i2c);diff --git a/include/linux/i2c-ocores.h b/include/linux/i2c-ocores.h index 4d5e57f..d1258ad 100644 --- a/include/linux/i2c-ocores.h +++ b/include/linux/i2c-ocores.h@@ -13,6 +13,7 @@ struct ocores_i2c_platform_data { u32 regstep; /* distance between registers */ + u32 regwidth; /* io read/write register witdth */ u32 clock_khz; /* input clock in kHz */ u8 num_devices; /* number of devices in the devices list */ struct i2c_board_info const *devices; /* devices connected to the bus */-- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html
-- Pengutronix e.K. | Wolfram Sang | Industrial Linux Solutions | http://www.pengutronix.de/ |
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