Hi, Alexandre On 9/12/2014 1:52 AM, Alexandre Belloni wrote:
From: Boris BREZILLON <boris.brezil...@free-electrons.com>Signed-off-by: Boris BREZILLON <boris.brezil...@free-electrons.com> Signed-off-by: Alexandre Belloni <alexandre.bell...@free-electrons.com> --- Changes in v2: - reworked the error path to really make the clock optional - Documented the new optional property .../devicetree/bindings/mtd/atmel-nand.txt | 1 + drivers/mtd/nand/atmel_nand.c | 25 ++++++++++++++++++++++ 2 files changed, 26 insertions(+) diff --git a/Documentation/devicetree/bindings/mtd/atmel-nand.txt b/Documentation/devicetree/bindings/mtd/atmel-nand.txt index c4728839d0c1..f71e2ebab15b 100644 --- a/Documentation/devicetree/bindings/mtd/atmel-nand.txt +++ b/Documentation/devicetree/bindings/mtd/atmel-nand.txt @@ -38,6 +38,7 @@ Optional properties: if don't want to use it. - Optional properties: - atmel,write-by-sram: boolean to enable NFC write by sram. + - clocks: phandle to the peripheral clock if it existsExamples:nand0: nand@40000000,0 { diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c index 9c5f717bda54..69e0eb1ace54 100644 --- a/drivers/mtd/nand/atmel_nand.c +++ b/drivers/mtd/nand/atmel_nand.c @@ -27,6 +27,7 @@ * */+#include <linux/clk.h>#include <linux/dma-mapping.h> #include <linux/slab.h> #include <linux/module.h> @@ -96,6 +97,8 @@ struct atmel_nfc { bool use_nfc_sram; bool write_by_sram;+ struct clk *clk;+ bool is_initialized; struct completion comp_ready; struct completion comp_cmd_done; @@ -2248,6 +2251,7 @@ static int atmel_nand_nfc_probe(struct platform_device *pdev) { struct atmel_nfc *nfc = &nand_nfc; struct resource *nfc_cmd_regs, *nfc_hsmc_regs, *nfc_sram; + int ret;nfc_cmd_regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);nfc->base_cmd_regs = devm_ioremap_resource(&pdev->dev, nfc_cmd_regs); @@ -2281,6 +2285,26 @@ static int atmel_nand_nfc_probe(struct platform_device *pdev)nfc->is_initialized = true;dev_info(&pdev->dev, "NFC is probed.\n"); + + nfc->clk = devm_clk_get(&pdev->dev, NULL); + if (!IS_ERR(nfc->clk)) { + ret = clk_prepare_enable(nfc->clk); + if (ret) + return ret;
In this case, the NFC clock is not enabled, so I think nfc->is_initialized should set to false. Otherwise, the nand driver will try to use the NFC without enabled the clock.
Is it better to move the code block nfc->is_initialized = true; dev_info(&pdev->dev, "NFC is probed.\n"); to just before the: return 0; Best Regards, Josh Wu
+ } else { + dev_warn(&pdev->dev, "NFC clock is missing"); + } + + return 0; +} + +static int atmel_nand_nfc_remove(struct platform_device *pdev) +{ + struct atmel_nfc *nfc = &nand_nfc; + + if (!IS_ERR(nfc->clk)) + clk_disable_unprepare(nfc->clk); + return 0; }@@ -2297,6 +2321,7 @@ static struct platform_driver atmel_nand_nfc_driver = {.of_match_table = of_match_ptr(atmel_nand_nfc_match), }, .probe = atmel_nand_nfc_probe, + .remove = atmel_nand_nfc_remove, };static struct platform_driver atmel_nand_driver = {
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