Hi Baruch,

On Sun, Jul 30, 2017 at 09:08:01AM +0300, Baruch Siach wrote:

On Fri, Jul 28, 2017 at 06:02:33PM +0200, Maxime Ripard wrote:

quoted

Hi, 

Thanks for the second iteration!

On Thu, Jul 27, 2017 at 01:01:35PM +0800, Yong Deng wrote:

quoted

Allwinner V3s SoC have two CSI module. CSI0 is used for MIPI interface
and CSI1 is used for parallel interface. This is not documented in
datasheet but by testing and guess.

This patch implement a v4l2 framework driver for it.

Currently, the driver only support the parallel interface. MIPI-CSI2,
ISP's support are not included in this patch.

Signed-off-by: Yong Deng <yong.deng-+3dxTMOEIRNWk0Htik3J/w@public.gmane.org>

[...]

quoted

quoted

+#ifdef DEBUG
+static void sun6i_csi_dump_regs(struct sun6i_csi_dev *sdev)
+{
+	struct regmap *regmap = sdev->regmap;
+	u32 val;
+
+	regmap_read(regmap, CSI_EN_REG, &val);
+	printk("CSI_EN_REG=0x%x\n",		val);
+	regmap_read(regmap, CSI_IF_CFG_REG, &val);
+	printk("CSI_IF_CFG_REG=0x%x\n",		val);
+	regmap_read(regmap, CSI_CAP_REG, &val);
+	printk("CSI_CAP_REG=0x%x\n",		val);
+	regmap_read(regmap, CSI_SYNC_CNT_REG, &val);
+	printk("CSI_SYNC_CNT_REG=0x%x\n",	val);
+	regmap_read(regmap, CSI_FIFO_THRS_REG, &val);
+	printk("CSI_FIFO_THRS_REG=0x%x\n",	val);
+	regmap_read(regmap, CSI_PTN_LEN_REG, &val);
+	printk("CSI_PTN_LEN_REG=0x%x\n",	val);
+	regmap_read(regmap, CSI_PTN_ADDR_REG, &val);
+	printk("CSI_PTN_ADDR_REG=0x%x\n",	val);
+	regmap_read(regmap, CSI_VER_REG, &val);
+	printk("CSI_VER_REG=0x%x\n",		val);
+	regmap_read(regmap, CSI_CH_CFG_REG, &val);
+	printk("CSI_CH_CFG_REG=0x%x\n",		val);
+	regmap_read(regmap, CSI_CH_SCALE_REG, &val);
+	printk("CSI_CH_SCALE_REG=0x%x\n",	val);
+	regmap_read(regmap, CSI_CH_F0_BUFA_REG, &val);
+	printk("CSI_CH_F0_BUFA_REG=0x%x\n",	val);
+	regmap_read(regmap, CSI_CH_F1_BUFA_REG, &val);
+	printk("CSI_CH_F1_BUFA_REG=0x%x\n",	val);
+	regmap_read(regmap, CSI_CH_F2_BUFA_REG, &val);
+	printk("CSI_CH_F2_BUFA_REG=0x%x\n",	val);
+	regmap_read(regmap, CSI_CH_STA_REG, &val);
+	printk("CSI_CH_STA_REG=0x%x\n",		val);
+	regmap_read(regmap, CSI_CH_INT_EN_REG, &val);
+	printk("CSI_CH_INT_EN_REG=0x%x\n",	val);
+	regmap_read(regmap, CSI_CH_INT_STA_REG, &val);
+	printk("CSI_CH_INT_STA_REG=0x%x\n",	val);
+	regmap_read(regmap, CSI_CH_FLD1_VSIZE_REG, &val);
+	printk("CSI_CH_FLD1_VSIZE_REG=0x%x\n",	val);
+	regmap_read(regmap, CSI_CH_HSIZE_REG, &val);
+	printk("CSI_CH_HSIZE_REG=0x%x\n",	val);
+	regmap_read(regmap, CSI_CH_VSIZE_REG, &val);
+	printk("CSI_CH_VSIZE_REG=0x%x\n",	val);
+	regmap_read(regmap, CSI_CH_BUF_LEN_REG, &val);
+	printk("CSI_CH_BUF_LEN_REG=0x%x\n",	val);
+	regmap_read(regmap, CSI_CH_FLIP_SIZE_REG, &val);
+	printk("CSI_CH_FLIP_SIZE_REG=0x%x\n",	val);
+	regmap_read(regmap, CSI_CH_FRM_CLK_CNT_REG, &val);
+	printk("CSI_CH_FRM_CLK_CNT_REG=0x%x\n",	val);
+	regmap_read(regmap, CSI_CH_ACC_ITNL_CLK_CNT_REG, &val);
+	printk("CSI_CH_ACC_ITNL_CLK_CNT_REG=0x%x\n",	val);
+	regmap_read(regmap, CSI_CH_FIFO_STAT_REG, &val);
+	printk("CSI_CH_FIFO_STAT_REG=0x%x\n",	val);
+	regmap_read(regmap, CSI_CH_PCLK_STAT_REG, &val);
+	printk("CSI_CH_PCLK_STAT_REG=0x%x\n",	val);
+}
+#endif

You can already dump a regmap through debugfs, that's redundant.

The advantage of in-code registers dump routine is the ability to
synchronize the snapshot with the driver code execution. This is
particularly important for the capture statistics registers. I have
found it useful here.

You also have the option to use the traces to do that, but if that's
useful, this should be added to regmap itself. It can benefit others
too.

quoted

quoted

+static irqreturn_t sun6i_csi_isr(int irq, void *dev_id)
+{
+	struct sun6i_csi_dev *sdev = (struct sun6i_csi_dev *)dev_id;
+	struct regmap *regmap = sdev->regmap;
+	u32 status;
+
+	regmap_read(regmap, CSI_CH_INT_STA_REG, &status);
+
+	if ((status & CSI_CH_INT_STA_FIFO0_OF_PD) ||
+	    (status & CSI_CH_INT_STA_FIFO1_OF_PD) ||
+	    (status & CSI_CH_INT_STA_FIFO2_OF_PD) ||
+	    (status & CSI_CH_INT_STA_HB_OF_PD)) {
+		regmap_write(regmap, CSI_CH_INT_STA_REG, status);
+		regmap_update_bits(regmap, CSI_EN_REG, CSI_EN_CSI_EN, 0);
+		regmap_update_bits(regmap, CSI_EN_REG, CSI_EN_CSI_EN,
+				   CSI_EN_CSI_EN);

You need to enable / disable it at every frame? How do you deal with
double buffering? (or did you choose to ignore it for now?)

These *_OF_PD status bits indicate an overflow error condition.

Shouldn't we return an error code then? The names of these flags could
be better too.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com